THE INFLUENCE OF ENVIRONMENTAL AND INDUCED CULTURAL STRESSES ON THE WINTER SURVIVAL-VINE PRODUCTIVITY COMPLEX IN VITIS LABRUSCA L VAR. CONCORD VINES A Disserfaflon Ior fIve Degree OI DII. D. MICHIGAN STATE UNIVERSITY Basil G. Stergios I975 w 3%? ngw ABSTRACT THE INFLUENCE OF ENVIRONMENTAL AND INDUCED CULTURAL STRESSES ON THE WINTER SURVIVAL-VINE PRODUCTIVITY COMPLEX IN VITIS LABRUSCA L. VAR. CONCORD VINES BY Basil G. Stergios Cold hardiness and its association with the produc- tivity of Vitis labrusca L. var. Concord vines was studied in the field and in the laboratory. Various methods for testing the viability of cold-stressed grape tissue were evaluated. Lowest bark temperature survival was adequately assessed by specific conductivity analysis for small sample sizes, and by tissue browning for large sample sizes. Tissue browning was the most practical method to assess cane and bud viability. The effect of site-induced air temperature on cold acclimation and deacclimation in Concord grape vines was assessed in southwestern Michigan. High and low vineyard sites generated distinct temperature-induced microclimatic environments where differences in intracultivar adaptation were possible. Changes in bark and bud hardiness were directly related to air temperature changes. These changes affected primary buds most, then the secondary buds, followed by the bark. Concord grape vines on the low Basil G. Stergios site produced bark and primary and secondary buds which were hardier during acclimation and deacclimation than bark and buds from high site vines. Evaluation of previous studies led to the concept that cultural stress could determinately influence cold hardiness. Since vine management is a complex of cultural practices, it was determined that evaluation of cultural stresses should include both hardiness and productivity measurements. Concord grape plants were culturally stressed by complete defoliation, pruning severity, cluster thinning, and trellis height from 1971 to 1973. Defoliation, pruning severity, and cluster thinning influenced bark and bud hardiness. The effect of trellis height on bark hardiness was inconclusive. Some increased hardiness was noted for low trellis buds. Defoliation resulted in delayed aCCli- mation in the fall and more rapid deacclimation in the spring. Effects of defoliation on bark and bud hardiness were more pronounced during the second year of treatment. Balance (30 + 10) pruning maximized the bark and bud hardi- ness of nondefoliated plants. Cluster thinning increased hardiness levels otherwise depressed by 60 + 10 pruning, particularly when the vines were defoliated. Thus, the greater hardiness sensitivity of under-pruned vines seems to be a result of over production. The tertiary bud was usually as hardy or slightly hardier than the secondary Basil G. Stergios bud with most treatments. The cultural stresses individually and collectively influenced vine size, and productivity as measured by yield, fruitfulness, berry size, soluble solids, clusters per vine, clusters per node, total vine sugar, berries per cluster, and cluster size. Leaf removal caused a reduction in all factors of productivity, particularly total vine sugar (59%), yield (50%), fruitfulness (37%), cluster number per node (23%), soluble solids (22%), and vine size (22%). Light (60 + 10) pruning increased the number of nodes retained which decreased vine fruitfulness. Yields were initially higher from lightly pruned vines than from balance pruned vines even though fruitfulness was low. Later, however, balance pruned vines yielded as much fruit and total vine sugar as lightly pruned vines while still maintaining a higher level of fruitfulness. Although cluster size and the number of nodes per vine increased on cluster thinned vines, fruitfulness, cluster number per node, and total vine sugar was reduced. Defoliation and cluster thinning interacted most frequently to lower vine productivity. The differential hardiness and productivity of primary and secondary buds led to a desire to determine the reason for their difference. A pilot study was under— taken to assess the effect of primary bud kill and removal on secondary shoot growth and productivity. A field technique was developed for primary bud destruction. Basil G. Stergios Field death of dormant primary buds of Concord grape was effectively simulated by in situ puncture with an aluminum needle super-cooled by liquid nitrogen. This allowed the subsequent development of the secondary buds for study. THE INFLUENCE OF ENVIRONMENTAL AND INDUCED CULTURAL STRESSES ON THE WINTER SURVIVAL-VINE PRODUCTIVITY COMPLEX IN VITIS LABRUSCA L. VAR. CONCORD VINES BY Basil G. Stergios A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Horticulture 1975 DEDICATION This dissertation is dedicated to two individuals. To my advisor, Stan Howell, who always shared and taught, both as a personal friend and as a scientist; and to my wife, Anita, who always worked hard and remained dedicated. ii ACKNOWLEDGMENTS I wish to express my sincere appreciation to the members of my committee: Drs. Stan Howell, David Dilley, Robert Olien, Eugene Mielke, Norman Good, Donald Ramsdell, Frank Dennis, and Robert Andersen for their guidance and critical inputs. I wish to thank William Grevelding, Robert Van Vleck, and Richard Haynor of the National Grape Cooperative; Dr. Nelson Shaulis of the Geneva Experiment Station; Robert Rogers, William Cronenwett, and Walter Spiech of Lawton, Michigan; Stephen Stackhouse and Maureen Myers of Michigan State University, for their continual help and guidance both in and out of the field. I wish to express my gratitude to fellow students and friends who aided, guided, and provided moral support in my research: Marie Ross, Loudes Alvarez, the De-La-Garza family, the Mendoza family, the Gonzales family, the Garcia family, the Gomez family, Skip Bittenbender, Susan (Engstrom) Bittenbender, Michael Byrne, and John Stuurwold. iii TABLE OF CONTENTS Page PREFACE O O O O O O O O O O O O O O O O 1 Introduction . . . . . . . . . 1 Freezing Injury and Death in WOody Plants. . . . 2 Environmentally Induced Acclimation and Deacclimation . . . . . . . . . . 3 Cold Hardiness and Plant Productivity . . . . . 8 Thesis Objectives. . . . . . . . . . . . 9 LITERATURE CITED . . . . . . . . . . . . . 12 SECTION ONE EVALUATION OF VIABILITY TESTS FOR COLD STRESSED PIANTS O O O O O I O O O O O I O O O 16 AbStraCto O O C O O O O O O O O O O 16 Materials and Methods . . . . . . . . . . 16 Results . . . . . . . . . . . . . . . 18 Discussion . . . . . . . . . . . . . . 20 Literature Cited . . . . . . . . . . . . 21 SECTION TWO EFFECT OF SITE ON COLD ACCLIMATION AND DEACCLIMATION IN Vitis labrusca L. var. Concord Vines. . . . . 22 AbStraCto O O O O O O I O O O O O O O 22 Introduction . . . . . . . . . . . . . 23 Methods and Materials . . . . . . . . . . 25 The Study Area. . . . . . . . . . . . 25 Sampling Procedures . . . . . . . . . . 26 Hardiness and Air Temperature Measurements . . 27 Results . . . . . . . . . . . . . . . 28 ACClimation O O O O O O O O O O O O O 29 Deacclimation . . . . . . . . . . . . 30 Discussion . . . . . . . . . . . . . . 32 Conclusions. . . . . . . . . . . . . . 34 iv Page LITERATURE CITED 0 O C O C O O O O C C O O 4 5 SECTION THREE EFFECTS OF DEFOLIATION, TRELLIS HEIGHT, AND CROPPING STRESS ON THE COLD HARDINESS OF Vitis labrusca L. var. Concord Vines. . . . . . . . . . . . 48 AbStraCt O O O O O O O O O O O O 0 O 48 Introduction . . . . . . . . . . . . 49 Materials and Methods . . . . . . . . . . 50 The Study Area. C O O O O O O O O O 50 Experimental Design and Sampling Procedures . . 51 Hardiness Measurements . . . . . . . . . 53 Results . . . . . . . . . . . . . . . 54 Bark Hardiness. . . . . . . . . . . . 54 Primary Bud Hardiness . . . . . . . . . 55 Secondary Bud Hardiness. . . . . . . . . 57 Tertiary Bud Hardiness . . . . . . . . . 59 Discussion . . . . . . . . . . . . . . 59 Defoliation. . . . . . . . . . . . . 60 Pruning Severity . . . . . . . . . . . 61 Cluster Thinning . . . . . . . . . . . 62 Trellis Height. . . . . . . . . . . . 62 LITERATURE CITED 0 O O O O O O O O O O O I 72 SECTION FOUR EFFECTS OF DEFOLIATION AND CROPPING STRESS ON THE SIZE AND PRODUCTIVITY 0F Vitis labrusca L. var. Concord Vines . . . . . . . . . . . . . 77 Abstract. . . . . . . . . . . . . . . 77 Introduction . . . . . . . . . . . . . 78 Methods and Materials . . . . . . . . . . 79 The Study Area. . . . . . . . . . . . 79 Experimental Design and Sampling Procedures . . 80 Results 0 o o o o o o Vine Size and Nodes Retained Yield. 0 O O O O O Fruitfulness and Clusters Per Node Cluster Number and Size. Vine Sugar . . . . . Berry Size and Number of Berries Per Cluster Soluble Solids. . . . Discussion . . . . . . Defoliation. . . . Pruning Severity . . Cluster Thinning . . Treatment Effects. . LITERATURE CITED . . . . . £2 Situ DESTRUCTION OF DORMANT CONCORD GRAPE PRIMARY BUDS WITHOUT SECONDARY BUD KILL SECTION FIVE Abstract. . . . . . . Literature Cited . . . . EP I LOGIIE O O O O O O . APPENDICES Appendix A. B. TREATMENT EFFECTS OF DEFOLIATION, PRUNING SEVERITY, AND CLUSTER THINNING ON THE PRODUCTIVITY OF Vitis labrusca L. var. CONCORD VINES FROM A HIGH (ELEV. 277 m) AND A LOW (ELEV. 256 m) SITE IN SOUTH- WESTERN MICHIGAN IN 1971, 1972, and 1973 PILOT STUDIES ON THE HARDINESS AND PRODUC- TIVITY OF PRIMARY AND SECONDARY BUDS OF CONCORD GRAPEVINES CONDUCTED IN SOUTH- WESTERN MICHIGAN IN 1972 AND 1973 vi Page 83 84 84 85 86 88 89 90 91 92 94 95 96 111 114 114 116 117 122 128 Appendix Page C. NUTRIENT LEVELS OF Vitis labrusca L. var. CON- CORD VINES BASED ON QUANTITATIVE ANALYSIS OF LEAF PETIOLES SAMPLED IN AUGUST, 1971 FROM A HIGH (ELEV. 277 m) AND A LOW (ELEV. 256 m) SITE IN SOUTHWESTERN MICHIGAN . . . . . . 138 D. MEAN mg STARCH/g DRIED Vitis labrusca L. var. CONCORD BARK AND WOOD TISSUE FROM HIGH AND LOW SITE, HIGH AND LOW TRELLISED STEMS SAMPLED DURING ACCLIMATION AND DEACCLIMATION IN 1971, 1972, AND 1973 IN SOUTHWESTERN MICHIGAN O O O O O O I O O I C O O 142 vii LIST OF TABLES Table Page SECTION ONE 1. Effects of freezing temp upon growth and tissue browning of cuttings of 4 species . . . . . 20 2. General summary of the advantages and disadvan- tages of viability tests for evaluation of woody plant hardiness . . . . . . . . . 20 SECTION TWO 1. Weekly mean maximum (max.) and minimum (min.) air temperatures (°C) for a high (H), well air-drained and a nearby low (L), poorly air- drained Concord grape vineyard in Van Buren Co., Michigan from fall, 1971 to spring, 1973 . . . . . . . . . . . . . . 36 SECTION FOUR 1. Productivity and vine size of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1971. . . . . . . . . . . . . . 97 2. Productivity and vine size of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1972. . . . . . . . . . . . . . 98 3. Productivity and vine size of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1973. . . . . . . . . . . . . . 99 4. Productivity and vine size of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1971 . 100 viii Table - Page SECTION FOUR 5. Productivity and vine size of Concord grape vines from a high (elev. 277 m) and a low ' (elev. 256 m) site in southwestern Michigan in 1972 . . . . . . . . . . . . . 101 6. Productivity and vine size of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1973. . . . . . . . . . . . . 102 SECTION FIVE 1. Primary and secondary Concord grape bud via- bility by the "browning test" in response to puncture by an aluminum, liquid N2- cooled needle for 5 time periods (n = 10 observations) . . . . . . . . . . . 115 2. Primary and secondary Concord grape bud via- bility by the "growth test“ in response to puncture by an aluminum, liquid Nz-cooled needle for 5 time periods (n = 10 obser- vations). . . . . . . . . . . . . 115 APPENDIX A A-l. Productivity of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1971. . . . . 122 A-2. Productivity of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1971. . . . . 123 A-3. Productivity of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1972. . . . . 124 A-4. Productivity of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1972. . . . . 125 ix Table Page APPENDIX A A-S. Productivity of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1973 . . . . . 126 A-6. Productivity of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1973 . . . . . 127 APPENDIX B 8-1. Effect of primary bud removal on secondary shoot productivity of balanced pruned, 4-AK trained, Concord grapevines harvested in October, 1972 . . . . . . . . . . . 132 B-2. Effect of primary bud removal on secondary shoot productivity of balanced pruned, GDC trained, Concord grapevines harvested in September, 1973 . . . . . . . ., . . . . . . 133 APPENDIX C C-l. Nutrient levels in August, 1971 of Concord grape vines based on quantitative analysis of leaf petiOIeS O O O O I O O O O O O O O 138 C-2. Nutrient levels in August, 1971 of Concord grape vines based on quantitative analysis of leaf petioles O O O C C O O O O O O O O 139 APPENDIX D D-l. Mean mg starch/g dried Concord grape stem tissue collected on October 2, 1971 from a high, well air-drained site . . . . . . 142 D-2. Mean mg starch/g dried Concord grape stem tissue collected on November 6, 1971 from a high, well air-drained site . . . . . . 143 Table Page APPENDIX D D-3. Mean mg starch/g dried Concord grape stem tissue collected on December 11, 1971 from a high, Well air-drained Site 0 o o o o o o o o 145 D-4. Mean mg starch/g dried Concord grape stem tissue collected on March 25, 1972 from a high, W611 air-drained Site 0 o o o o o o o o 147 D-5. Mean mg starch/g dried Concord grape stem tissue collected on April 15, 1972 fromza high, well air-drained site . . . . . . . . . 149 D-6. Mean mg starch/g dried Concord grape stem tissue collected on December 15, 1972 from a high, W611 air-drained Site 0 o o o o o o o o 151 D-7. Mean mg starch/g dried Concord grape stem tissue collected on April 15, 1973 from a high, well air-drained site . . . . . . . . . 153 xi LIST OF FIGURES Figure PREFACE Schematic view of sequential development of slow- freezing death in woody plant tissue . . . . SECTION ONE Effect of low temp stress on stem tissue via- bility as determined by specific conduc- tiVitY O O O O O O O I O O C O O 0 Effect of low temp stress on stem tissue via- bility as determined by triphenyl tetrazolium chloride (TTC) reduction . . . . . . . . Examples of freezing curves used to determine the viability of low temp stressed stem tissues (FP - Freezing Point) . . . . . . SECTION TWO Acclimation of living bark, and of primary and secondary buds from balance pruned Concord grape vines in a high (elev. 277 m), well air-drained site and a low (elev. 256 m), poorly air-drained site in 1971 in van Buren Co., Michigan . . . . . . . . . Acclimation and deacclimation of living bark, and of primary and secondary buds from balance pruned Concord grape vines in a high (elev. 277 m), well air-drained site and a low (elev. 256 m), poorly air-drained site during 1971 and 1972 in Van Buren Co., Michigan . . . . . . . . . . . . . xii ’ Page 17 18 19 38 40 Figure Page SECTION TWO 3. Deacclimation of living bark, and of primary and secondary buds from balance pruned Concord grape vines in a high (elev. 277 m), well air-drained site and a low (elev. 256 m), poorly air-drained site in Van Buren Co., Michigan in 1972 . . . . . . . 42 4. Deacclimation of living bark, and of primary and secondary buds from balance pruned Concord grape vines in a high (elev. 277 m), well air-drained site and a low (elev. 256 m), poorly air-drained site in 1973 in Van Buren Co., Michigan . . . . . . . . 44 SECTION THREE 1. Acclimation and deacclimation patterns of living bark and primary buds of Concord grape (Vitis labrusca L.) vines from October 2, I97I Eo April 29, 1972 . . . . . 65 2. Acclimation and deacclimation patterns of living bark and primary buds of Concord grape (Vitis labrusca L.) vines from October-37_ID72 to April 15, 1973 . . . . . 67 3. Acclimation and deacclimation patterns of secondary and tertiary buds of Concord grape (Vitis labrusca L.) vines from October 2, 1971 to April 29, 1972 . . . . . 69 4. Acclimation and deacclimation patterns of secondary and tertiary buds of Concord grape (Vitis labrusca L.) vines from October 5,’I9727to April 15, 1973 . . . . . 71 SECTION FOUR l. The effect of defoliation and pruning severity on the yield (Kg) from high site Concord grape vines in 1972. . . . . . . . . . 104 xiii Figure Page SECTION FOUR 2. The effect of defoliation and cluster thinning on the yield (Kg) from low site Concord grape vines in 1972 . . . . . . . . . 104 3. The effect of defoliation and cluster thinning on the No. clusters per node from low site Concord grape vines in 1972 . . . . . . 104 4. The effect of defoliation and cluster thinning on the yield (Kg) from high site Concord grape vines in 1973 . . . . . . . . . 104 5. The effect of defoliation and cluster thinning on the yield (Kg) from low site Concord grape vines in 1973 . . . . . . . . . 104 6. The effect of defoliation and cluster thinning on the fruitfulness (Kg per node) of low site Concord grape vines in 1972. . . . . 104 7. The effect of defoliation and cluster thinning on the fruitfulness (Kg/node) of high site Concord grape vines in 1973 . . . . . . 106 8. The effect of defoliation and cluster thinning on the No. of clusters per vine from high site Concord grape vines in 1972. . . . . 106 9. The effect of defoliation and cluster thinning on the No. of clusters per vine from low site Concord grape vines in 1972. . . . . 106 10. The effect of defoliation and cluster thinning on the No. of clusters per vine from low site Concord grape vines in 1973. . . . . 106 11. The effect of defoliation and pruning severity on the No. of clusters per vine from high site Concord grape vines in 1973. . . . . 106 12. The effect of defoliation and cluster thinning on the cluster size (g/cluster) from high site Concord grape vines in 1973. . . . . 106 xiv Figure Page SECTION FOUR 13. The effect of defoliation and cluster thinning on the total vine sugar (Kg) of high site Concord grape vines in 1971 . . . . . . 108 14. The effect of defoliation and cluster thinning on the total vine sugar (Kg) of high site Concord grape vines in 1973 . . . . . . 108 15. The effect of defoliation and cluster thinning on the total vine sugar (Kg) of low site Concord grape vines in 1973 . . . . . . 108 16. The effect of defoliation and pruning severity on the total vine sugar (Kg) of high site Concord grape vines in 1972 . . . . . . 108 17. The effect of defoliation and pruning severity on the berry size (g) from high site Concord grape vines in 1972 . . . . . . . . 108 18. The effect of defoliation and cluster thinning on the berry size (9) from high site Concord grape vines in 1973 . . . . . . . . 108 19. The effect of pruning severity and cluster thinning on the berry size (9) from low site Concord grape vines in 1973 . . . . 110 20. The effect of defoliation and cluster thinning on the No. of berries per cluster from high site Concord grape vines in 1973. . . . . . . . . . . 110 21. The effect of defoliation and pruning severity on the soluble solids of the fruit of high site Concord grape vines in 1973 . . . . . . . . . . . . 110 SECTION FIVE 1. A. Diagram of the leaf axil of Concord grape showing relative positions of leaf scar, lateral shoot and 3 dormant buds; B. Longi- section in the plane of the axis through a node of Concord grape showing 3 dormant buds 115 XV Figure Page SECTION FIVE 2. Portable apparatus for in situ destruction of Concord grape primary—Buds, consisting of an aluminum rod with a sharpened tip super- cooled with liquid N2 . . . . . . . . . 115 EPILOGUE 1. Schematic representation of the relationship between viticultural stress and the vine hardiness - vine productivity complex in Concord grape. . . . . . . . . . . . 120 2. Schematic representation of the relationship between minimal viticultural stress and the vine hardiness - vine productivity complex in Concord grape . . . . . . . . 121 APPENDIX B B-l. Effects of primary bud removal on secondary shoot growth from May 16 to June 16, 1972 Primary buds were removed May 14, 1972 . . . 135 B-2. Effects of primary bud removal on secondary shoot growth of Concord grape vines from May 13 to July 4, 1974. . . . . . . . . 137 xvi PREFACE PREFACE Introduction Since cultivated woody plants are immobile, their distribution, survival, and productive capacity are con- trolled by their ability to adapt to conditions imposed upon them by the environment and by man. Such conditions include t0pography, soil conditions, drought, photoperiod, cold, and cultural practice. Cold stress appears to be one of the most important factors regulating the distribution of cultivated plant populations (9, 22). Freezing damage to economically important plants presents problems of economic concern in both temperate and subtropical regions. COping with environmental stresses, in particular cold stress, con- stitutes an important part of the plant's survival strategy. Strategically, cold may be dealt with by the plant in several ways. One involves the advantageous use of low temperature. Seeds of Hieracium aurantiacum L. deposited late in the growing season will not germinate as readily as those deposited early unless they are subjected to a cold period (34). Seedlings arising from early deposited seed would be sufficiently developed to successfully over- winter, while those arising late would not. Cold is probably 1 utilized to break seed dormancy, affording the seedling an entire growing season for establishment. Another strategem for plant survival involves protection from injury and death from cold stress. Less hardy woody plants may be physically protected by a low growth habit when over- wintering in areas with deep snow cover (8). External protection against cold stress is largely unavailable for larger woody plants. They avoid cold injury by using metabolic energy (20) to initiate the biologically active (42) process of acclimation in response to natural rhythms (8, 42). In cold climates, the cold hardiness and fruit productive capacity of cultivated woody plants are inextricable. Their capacity to produce fruit is important primarily for economic reasons. Often, however, the pro- ductive plant parts are the most susceptible to cold injury. The strategy thus requires back-up mechanisms to assure survival: via enhanced vegetative growth, apomixis, or the activation of secondary plant parts. Freezing Injury and Death in Wbody Plants There appear to be two general approaches to the question of freezing injury in woody plants. The first approach involves primary direct injury (18), where injury and death always result from intracellular ice formation (l8, l9), usually occurring when tissues are rapidly frozen (41, 42). The lethality of intercellular ice also depends on the amount of recrystalization occurring during warming, with slow warming producing the greater amount (19, 29). Since intracellular ice formation in woody plants is rarely observed in nature, the mechanism of primary direct injury remains obscure. However, it seems reasonable that physical disruption of the protoplasm, or rupture of the cell membrane itself by large ice crystals may be involved (18, 19). Olien gt 31. (21) observed that when hardened winter barely was damaged during cold weather following a mid-winter thaw, large ice masses formed which ruptured the xylem vessels in the crown. Injury and death in woody plant cells most commonly occurs as a result of slow-freezing stress. Many theories concerning this process have been proposed and are discussed at length by Levitt (18), Vasil'yev (41), Mazur (19), Tumanov and Krasavtsev (39), and by Weiser (42). Freeze- induced dehydration of the protoplast appears to be the most reasonable theory to explain injury and death in hardy woody plants, and the steps of this process as pro- posed by Weiser (42) are outlined in Figure 1. Environmentally Induced Acclimation and’Deacclimation Woody plants adapted to temperate regions are resistant to freezing stress (1, 42) because of their ability to acclimate (18, 19, 42). Alden and Herman (l) .onma .Homfloz Hmumfi .OSmmHu ucmam hooos cw Symon mcfiumOHMI3oam mo usmEmoHO>OU Hafiusosvmm mo 30H> aflpmsmsom .H .mHm E / cowgmaosmum OHEmMHQODONMI/ Exameoxm‘ mmcmsumumsoo owfimmHmououm amammmm¢ ammo 935. some muse 6633 One 13? 20mm ezngos o~m .msmu mcwmmouomo nuwz mow HMHSHHOOIMHuxO op uso on umaoaamo mo usosm>oe 30am omscwucoo quuoz moH ‘ woe unawaaoomuuxm _ , mmqbqqmoemaxm on D50 O m «0 some mHquozmdqm 9H. .50 mass: U smmmaoxm E II. .mamfieosomm 00mm Im>oa 30am . Emu UHzmmqmoaomm osmmdu mcammouomc mo mOdMZHmmm mo onadmez . . I cowoum ma Hones magmawm>m haatwou nouns msHHooo Hosuusm mmuflmm . m¢qbqqmummBzH Emmeoxm Alluo sowummmmoum UHQMHII. zH wzHNmmmm II—UquooummmDm— 9mmHm qubqqmodmaxm point out that the ability of plants to withstand cold stress depends on an inherent annual rhythm of complex metabolic functions that has evolved through plant- environment interaction. It is widely reported that cold acclimation in nature is a two-phase, sequential process (5, 10, 15, 32, 40, 42) dependent upon active metabolic processes in the early stages (5, 42). Investigations have shown (5, 10, 13, 40) that the first phase of acclimation is not temperature dependent, rather is initiated by a photoperiodic response induced by short-day perceptors in the leaves. Woody plants will begin to acclimate with a short day stimulus even when temperatures remain high (10). However, either low tempera- tures or short days can induce acclimation in the absence of the other inductive factor (5). Growth cessation appears to be a necessary pre- requisite to cold acclimation (5, 10, 40, 42) and the induction of growth cessation is probably one of the prime functions of short days in the natural cold acclimation of plants (5). Plants will not acclimate even if they are chilled to 0°C while they are actively growing (6, 26). Weiser (42) suggests that short days probably function as a natural early warning system. He further suggests that the first stage of acclimation appears to involve two dis- tinct events, growth cessation and the initiation of metabolic changes which facilitate the plant's response to low temperatures during the second phase of acclimation. The key factor in photoperiodic acclimation appears to be growth cessation rather than rest induction because low temperature can stop growth and bring about acclimation without inducing rest (10). Studies suggest that the light stimulus results in the production of a translocatable hardiness factor(s) (4, 16, 32, 33) which causes acclimation. Long-day induced leaves are the source of a translocatable factor(s) which inhibits cold acclimation (16), while short-day induced leaves are the source of translocatable hardiness promoting factor(s) (5, 10, 16). Although investigators agree that a translocatable hardiness promoter(s) exists, the nature of the promoter(s) is still being debated. Opinions appear to be divided along two lines. Weiser (42) and his associates (10), Irving and Lanphear (l7), and Roberts (26) have suggested that the promoter(s) is a hormone. Steponkus (32), however, suggests the hardiness promoter is most likely sucrose. He argues that sucrose is necessary during the second phase of acclimation because frost sensi- tive proteins alter their configurations when subjected to low temperature, and their subsequent stabilization is dependent upon the binding of sucrose. This is accomplished when the protein assumes a new configuration or composition which provides sites which bind with the hydroxyl groups of sucrose. This stabilization is manifested as an increase in hardiness. Steponkus (32) supports his argument from his finding that sucrose will replace the light requirement for initiating acclimation in Hedra helix. Once acclimation is underway, and the hardiness promoter(s) has been activated, the second phase of accli- mation begins. The second phase of acclimation appears to be induced by low temperatures. Howell and weiser (10) found that young Haralson apple trees failed to acclimate beyond a certain point in the absence of frost. The second phase of acclimation was always initiated when the trees were exposed to frost. In addition, they found that the second, or low temperature induced phase of acclimation does not involve a translocatable factor(s) (10). A third phase of acclimation has also been described (39, 42), where prolonged eXposure to very low temperatures causes the woody tissue to attain hardiness not found in nature. This type of hardiness is quickly lost (39). Dehardening and rehardening processes in woody plants appear to be related to the state of dormancy. Two phases of dormancy have been identified: rest and quiescence (42). Plants apparently are at rest immedi— ately following the onset of acclimation, and during this stage they tend to maintain hardiness even when subjected to higher air temperatures (14). After the cold require- ment is satisfied, rest gives way to quiescence and the plants may then loose hardiness (deharden) readily when air temperatures rise (3). During the quiescent period, woody plant tissue may also reharden after loss of hardiness, when exposed to fluctuating air temperatures (3, 7, 10, ll, 25). Howell and Weiser (11) found that dehardening of living apple bark is only partially rever- sible. Once dehardening had begun, the bark did not reharden beyond the killing temperature on the day preced- ing the final day of dehardening. This lethal temperature increased with each successive day of dehardening. Cold Hardiness and Plant Preductivity Low temperatures and a short growing season, which are characteristic in cold climates, enhance the importance of the cold hardiness-productivity complex in cultivated woody plants such as Vitig labrusca L. var. Concord. Cultural stresses induced by vineyard management techniques directly influence the cold hardiness of the vine (36). Cultural stresses can have a synergistic effect on vine productivity. While they can exert a direct influence on productivity (37), reduced cold hardiness by improper vine management will in turn result in reduced yield, fruitful- ness, and fruit quality (30, 31, 37). It is evident, then, that vine management for cold hardiness cannot and should not be separated from other management techniques. The vine must accomplish three physiological functions if it is to be economically satisfactory to the grower (12): (a) it must mature the grape crop it is carrying; (b) it must initiate and carry out the differentiation and ontogeny of shoots and flower clusters for the following season; and (c) it must mature the canes to insure acclimation and adequate cold hardiness. These functions can be adequately achieved if vineyard cultural practices are implemented with both cold hardiness and production in mind. The sexual back-up mechanism for survival in Concord grape vines is not only part of the survival strategy, but also can be of economic importance to growers. The primary bud (35) which is the most productive (2, 24, Appendix) part of the compound bud, is also the least cold hardy (23, 36, 38). However, the secondary bud, which will usually develOp in the absence of a viable primary bud, is hardier (23, 36, 38) and can produce up to 70% of the normal crOp (43, Appendix) under ideal circumstances. Thesis Objectives Cultural stresses like defoliation, pruning severity, and cluster thinning have a synergistic effect on vine pro- ductivity. That is, while cultural stresses can exert a direct influence on vine productivity, reduced cold hardi- ness by improper vine management will, in turn, result in reduced yield, fruitfulness, and fruit quality. Therefore, I suggest that vine management for hardiness cannot and should not be separated from other management techniques. 10 When viticultural stresses are minimized, both vine hardi- ness and vine productivity are simultaneously improved. Improved hardiness increases productivity by increasing vine fruitfulness, and increased productivity stimulates proper vine vigor. A proper vine balance encourages maximum hardiness. The purpose of this thesis was to provide a broader understanding of the cold hardiness-vine productivity com- plex in culturally stressed Concord grape plants. The following studies were undertaken in an attempt to eluci- date the manner in which vine hardiness and productivity are related. The specific goals of the research were five-fold: (a) to evaluate and determine the reliability of several viability tests for Concord grape vines. In order to effectively evaluate cold hardiness in grape vines, a suitable test for viability had to be determined. What effectively determines viability in one type of plant may not do so for another; (b) to determine the effect of site- induced air temperature on cold acclimation and deaccli- mation in Concord grape vines. In order to obtain a basic understanding of the nature of cold hardiness in Concord grape canes and buds, the effect of air temperature on acclimation and deacclimation under natural conditions necessitated elucidation. Differences in site elevation provided the distinct temperature regimes necessary for 11 this purpose; (c) to determine the effects of hand defoli- ation, pruning severity, cluster thinning, and trellis height on the cold hardiness of Concord grape vines; (d) to determine the individual and combined effects of hand defoliation, pruning severity, and cluster thinning on the size and productivity of Concord grape vines. Cold hardi- ness and vine productivity are inextricably associated and are influenced by cultural stresses imposed upon the vine by vineyard management practices. The studies in sections 3 and 4 were designed to gain some insight into the nature of the hardiness-vine productivity complex; and (e) to design and implement a workable method for simulating freezing death of the primary bud in the field without injuring the secondary bud of Concord grape vines. The differential hardiness and productivity of primary and secondary buds led to a desire to determine the reason for their dif- ference. In order to assess the effect of primary bud kill and removal on secondary shoot growth and productivity, an effective field technique had to be developed for primary bud destruction. The technique described in section 5 allowed the subsequent development of the secondary buds for study. This dissertation is presented as three manuscripts prepared to meet the literary requirements of the American Journal of Enology and Viticulture, to which each will be submitted; and two published articles. LITERATURE CITED 10. 11. LITERATURE CITED Alden, J. and R. K. Herman. 1971. Aspects of the cold-hardiness mechanism in plants. Bot. Rev. 37(1):,37-142. Clark, J. H. 1936. Injury to buds of grape varieties caused by low temperatures. Proc. Amer. Soc. Hort. Sci. 34: 408-413. Edgerton, L. J. 1960. Studies on cold hardiness of peach trees. Cornell Univ. Agr. Expt. Sta. Bul. 958. Fuchigami, L. H., D. R. Evert, and C. J. weiser. 1971. A translocatable cold hardiness promoter. Plant Physiol. 47: 164-167. , C. J. Weiser, and D. R. Evert. 1971. Induction of cold acclimation in Cornus stolonifera Michx. Plant Physiol. 47: 98-103. Glerum, C., J. L. Farrar, and R. L. McLure. 1966. A frost hardiness study of six coniferous species. For Chron. 42(1): 69-75. Hamilton, D. B. 1973. Factors influencing dehardening and rehardening of Forsythia intermedia stems. J. Amer. Soc. Hort. Sci. 98(2): 22I-223. Howell, G. S. 1969. The environmental control of cold hardiness in Haralson apple. Ph.D. thesis. Uni- versity of Minnesota, St. Paul. 64 pp. , and C. J. Weiser. 1968. What makes plants hardy? Horticulture 46: 19-20; 45. and . 1970. The environmental con- trol of coId’achimation in apple. Plant Physiol. 45: 390-394. and . 1970. Fluctuations in the cold resistance of apple twigs during Spring dehardening. J. Amer. Soc. Hort. Sci. 95(2): 190-192. 12 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 13 Howell, G. S., and B. G. Stergios. 1975. Vine manage- ment effects on cold hardiness. Eastern Grape Grower. In press. Hurst, C., T. C. Hall, and C. J. Weiser. 1967. Reception of the light stimulus for cold acclimation in Cornus stolonifera Michx. HortScience 2(4): 164-I66. Irving, M. R., and F. O. Lanphear. 1967. Dehardening and the dormant condition in Acer and Viburnum. Proc. Amer. Soc. Hort. Sci. 9I: 699-705. and . 1967. Environmental control of coId hardiness in woody plants. Plant physiol. 42: 1191-1196. and . 1967. The long day leaf as a source of coIH Hardiness inhibitors. Plant Physiol. 42: 1384-1388. and . 1968. Regulation of cold Harainess in Acer negundo. Plant Physiol. 43: 9-13. Levit, J. 1972. Responses of plants to environmental stresses. Academic Press, New York. 697 pp. Mazur, P. 1969. Freezing injury in plants. Ann. Rev. Plant Physiol. 20: 419-448. . 1967. Freezing stresses and survival. Ann. Rev. Plant Physiol. 18: 387-408. , B. L. Marchetti, and E. V. Chomyn. 1968. Ice structure in hardened winter barley. Mich. State Univ. Agr. Exper.Sta. Quarterly Bul. 50(4): 440-448. Parker, J. 1963. Cold resistance in woody plants. Bot. Rev. 29(2): 123-201. Pogosyan, K. S., and A. Sakai. 1969. Freezing resistance in grape vines. Hokkaido Univ., Low Temp. Sci. Ser. B: 125-144. , and M. M. Sarkisova. 1967. Frost resistance 0 grape varieties in relation to the condition of hardening. Soviet Plant Physiol. 14: 886-891. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 14 Proebsting, E. L. 1963. The role of air temperatures and bud development in determining hardiness of dormant Elberta peach fruit buds. Proc. Amer. Soc. Hort. Sci. 83: 259-269. Roberts, D. W. A. 1971. The effect of CCC and Gibberellins A3 and A7 on the cold hardiness of Kharkov 22 MC winter wheat. Can. J. Bot. 49(5): 705-711. Sakai, A. 1966. Temperature fluctuations in wintering trees. Physiol. Plantarum 19: 105-114. . 1970. Freezing resistance in willows from different climates. Ecology 51(2): 487-491. , and S. Yoshida. 1967. Survival of plant tissue at super low temperature VI. Effects of cooling and rewarming rates on survival. Plant Physiol. 42: 1695-1701. Shaulis, N. 1971. Vine hardiness a part of the problem of hardiness to cold in New York vineyards. Proc. New York State Hort. Soc. 116: 158-167. , J. Einset, and A. B. Pack. 1968. Growing cold tender grape varieties in New York. New York Agr. Expt. Sta. Bul. No. 821. 16 pp. Steponkus, P. 1971. Cold acclimation of Hedera helix, evidence for a two phase process. Plant PEysioI. 47: 175-180. , and F. O. Lanphear. 1967. Light stimulation of cold acclimation: production of a translocatable promoter. Plant Physiol. 42: 1673-1679. Stergios, B. G. 1975. Achene production, dispersal, seed genmination and seedling establishment of Hieracium aurantiacum L. in an old field community. Can. J. Bot. *In preparation. , and G. S. Howell. 1974. In situ destruction of dormant 'Concord' grape primary buds without secondary bud kill. HortScience 9(2): 120-122. and . 1975. Effects of defoliation, trelIis heigHt, and cropping stress on the cold hardiness of 'Concord' (Vitis labrusca L.) grape vines. Amer. J. Enol. Viticult. In preparation. 37. 38. 39. 40. 41. 42. 43. 15 Stergios, B. G., and G. S. Howell. 1975. Effects of defoliation and cropping stress on the size and pro- ductivity of 'Concord' (Vitis labrusca L.) grape vines. Amer. J. Enol. VIticul. In preparation. and . 1975. Effect of site on cold achimation and deacclimation patterns in 'Concord' (Vitis labrusca L.) grape vines. Amer. J. Enol. Viticult. In preparation. Tumanov, I. I., and O. A. Krasavtsev. 1959. Hardening of northern woody plants by temperatures below zero. Soviet Plant Physiol. 6(6): 663-673. Van Hyustee, R. B., C. J. Weiser, and P. H. Li. 1967. Cold acclimation in Cornus Stolonifera Michx. under natural and controlled photoperiod and temperature. Bot. Gaz. 128: 200-205. Vasil'yev, I. M. 1956. Wintering of plants. Am. Inst. Biol. Sci., English trans. J. Levitt, ed. Washington, 1961. 300 pp. weiser, C. J. 1970. Cold resistance and injury in woody plants. Science 169: 1269-1278. Wiggans, G. B. 1926. A study of the relative value of fruiting shoots arrizing from primary and secondary buds of the Concord grape. Proc. Amer. Soc. Hort. Sci. 23: 293-296. SECTION ONE EVALUATION OF VIABILITY TESTS FOR COLD STRESSED PLANTS Reprinted from Journal of the American Society for Horticultural Science Vol. 98, No. 4, July 1973 Evaluation of Viability Tests for Cold Stressed Plantsl Basil G. Stergios and Gordon S. Howell, Jr. Michigan State University, East Lansing Abstract. The reliability and convenience of 5 viability tests were evaluated. Growth and tissue browning were the most reliable tests, but they required considerable time and were qualitative. Triphenyl tetrazolium chloride (TTC) reduction and specific conductivity were satisfactory for grape, but TTC was not as reliable as specific conductivity for cherry and raspberry. Neither test proved satisfactory for strawberry. A second exotherrn always indicated living stems and the absence of a second exotherm accurately predicted stem death. Freezing curves for raspberry showed the stems to be 5 degrees hardier than the control growth tests indicated. Interest in stress physiology of horticultural plants has increased in recent years. The understanding of cold hardiness is rapidly expanding (l, 11, 21). Parker (17) reported the difficulty of determining whether a small sample of tissue or entire organism is still alive after a stress treatment. Dexter et al. (3) recognized the necessity for rapid methods of measuring viability of plant tissue and were among the first to develop a test for this purpose. Steponkus and Lanphear (19) pointed out that a prerequisite to conducting research in cold hardiness is a reliable method to determine tissue viability. They stated that the method should “eliminate bias associated with visual observations, be based on a quantitative system that can be analyzed statistically, utilize small quantities of tissue, be relatively quick, and be capable of predicting the future performance of the plant” (19). The purpose of the present study was: 1) to determine the reliability of several viability tests, and 2) evaluate these tests under the same conditions on different plant species. A test was considered reliable if it effectively distinguished between living and dead tissue. Convenience was assessed based on the time lag between stress and evaluation, amount of effort involved, and thed need for specialized equipment to evaluate the material un er test. Materials and Methods Growth, tissue browning, triphenyl tetrazolium chloride (TTC) reduction, specific conductivity, and double freezing point were used to evaluate viability of cold stressed plants of 4 different species: ‘Montmorency’ sour cherry (Prunus cerasus L), ‘Concord’ grape (Vitis labrusca L.), ‘Latham’ raspberry (Rubus strigosus Michx.), and ‘Midway’ strawberry (Fragaria sp.). The tissue evaluated consisted of excised stems of current season’s growth obtained from plants under cultivation in the field. Three-node sections from the mid-portion of cherry shoots and raspberry canes were used. Single-node stem sections cut in the mid-point of the intemode, were made from the mid-portion of 10 to 20-node grape canes. Strawberry crowns were taken from 2-year-old plants and the crowns stripped of all leaves and petioles. The sections of cherry, grape, and raspberry were cut to 12 cm in length. Care was taken to insure that the samples for a particular species were of com- parable caliper. Hardiness was determined on May 2 and May 10, 1971 by subjecting the material to a controlled freezing stress as described by Howell and Weiser (9). Three test samples per treatment were labeled and placed immediately into a series of vacuum flasks which were then cooled in a deep freeze at approximately 10°C/hr. A 26-gauge thermocouple was inserted in the pith of 1 stern in each flask to monitor sample temp. Received for publication February 14, 1973. Michigan Agricultural Experiment Station Journal Article Number 6241. J. Amer. Soc. Hort. Sci. 98(4):325-—330. 1973. Flasks were removed from the freezer at 5°C intervals and allowed to warm slowly to ambient temp. Growth and tissue browning. The tissue browning test for viability has been used both for direct determination of injury (6, 8, 9) and as a control for evaluating the responses of more quantitative tests (5, 20). The growth test has been used in a similar manner (4, 19). Cold stressed stems were placed in sand on a mist propagation bench in a 23 .9°C (75°F) greenhouse for 1 month. Stems were considered alive if root growth, callusing, or bud break occurred. The stems were also considered alive if the tissue appeared green in the absence of growth after 30 days. Both the percentage of cuttings showing growth, and the percent survival were recorded. Additional material was placed in a humid chamber and incubated at ambient temp for 14 days, after which it was dissected and visually inspected for injury. The stems were recorded as dead if the cambium and the phloem were brown. The results were tabulated as a percentage of the stems surviving at each temp. Specific conductivity. Dexter et a1. (3, 4) were among the first to describe a workable procedure for the use of specific conductance to relate change in electrolyte concentration to levels of low temp injury in plant tissues. Wilner (22 23) improved the test by expressing the specific conductivity of diffused electrolytes as a percent of the total extracted by boiling water. ‘ The method used was similar to that used by Wilner (22, 23). Freeze stressed cherry, grape, raspberry, and strawberry material was cut into 1 cm sections, halved, weighed, and placed in large culture tubes with distilled water (3 .ml/g of tissue). The reliability of the specific conductivity test for grape was enhanced by removing the non-living bark before sectioning. The material was incubated for 24 hr at ambient temp, the initial conductivities (reciprocal ohms) measured, and the samples autoclaved at 121°C for 1 hr. The final conductivities were measured after an additional 24 hr at ambient temp. The specific conductance was calculated as initial conductivity x 100 divided by final conductivity. Triphenyl tetrazolium chloride (TTC). The triphenyl tetrazolium chloride test was refined and meaningfully adapted as a tissue viability test by Steponkus and Lanphear (l9), and the procedure they reported was utilized. Cold hardiness was expressed as optical density (recorded at 530 my on a Bausch and Lomb 340 spectrophotometer) of solutions from stressed tissue x 100 divided by the optical density of solutions from controls. High percentages of TTC reduction indicated living tissue, low percentages indicated dead tissue. Data for specific conductivity and TTC reduction were processed statistically using an analysis of variance, and the means were compared across dates using Tukey’s w procedure (18). 17 Multiple freezing points. When water forms ice, heat is given off (exotherrn) and tissue temp rises temporarily (15, 21). Two exotherrns normally are observed in living tissue, only 1 in dead tissue (10, 14, 15, 16, 21). The multiple freezing point technique described by McLeester et a1. (15) was used. Samples were frozen at a rate of 10°C/hr, thawed, and then refrozen at the rate of about 60°C per hr. The resultant freezing curves were then compared and evaluated. Specific conductivity and TTC reduction values depicted Grape W n ._Jfi 9°. 05% CON OH“! 2 —- ALIVE O.- —‘— - U CRITICAL WING: ------ wear: can __< 70‘ o-flAY K) A IMV 2 I IJAN 28 MEAN S at SPECIFIC CONDUCTIVITY 20. D! -5 45 ' visfi 4'5 ' is TEMPERATURE re) Raspberry 904 , 80‘ N‘x l lc mu! //‘ ‘ I" / '4 I 60 / l [I / .01 /’ MEAN S of SPECIFIC CONDUCTIVLTY 8 w‘ 0 “Y 2 AUAY IO 20( 1 sum .6 ————-CRITICAL RANGE --------- -uuo on [0-4 as confluence . If. 4'0 4; -2'0 -2'5 TEMPERATURE (°C ) r-ssrf E7154“ D 7: graphically show the viability status of the 4 plant mate] "‘;‘_.,._._.,. ,. .' evaluated. The first range (solid line) indicates non-lethal te; a The last range (dotted line) indicates the lethal range, i.e. tr / at which sufficient injury occurred to prevent growth. ' ,,. It??? I: if. 2! middle, or critical range (broken line) indicates that dc / occurred somewhere within that 5°C interval based on growth test. Cherry f 704 j \ \\ ““0 60< ,x' ). I: Z '9’“ \ o \\ S “5 u l 404 . I 9 l E i u m a ”301 ‘8 a o - rm 2 2 ZOJ ‘ ' HAY l0 :5 - ALIVE on 2 -— — -— - cameu RANGE -------- - use CA ”I ' sex confluence . 1g; -3 46 4'5 .50 is TEMPERATURE (°C) Strawberry .0. ’9 90‘ III/,/+ ,1 i 90- I N/ ‘ I, i ’I E ' \\ | III/’.# UNI \ . "I” | a ‘2” . 3 6m ‘ o / l , / E r I G 50‘ l l ‘ ‘ J If , . m . 40< I 1 ‘5 l I ‘2! 30+ o-uav : N O'IAY l0 2 20, -—r—-—-CRIYICAL met -------- oouo on out confluence - :m. 00 t 6 -3 J0 J5 TEMPERATURE (’C) Fig. 1. Effect of low temp stress on stem tissue viability as determined by specific conductivity. Means between dates are 326 compared using the Tukey statistic. J. Amer. Soc. Hort. Sci. 98(4):325—330. -19 i1“- ~15 40 a fi .‘fi «'1:- 197.“ . ‘ 20 Table I. Effects of freezing temp upon growth and tissue browning of cuttings of 4 species. Values indicate percent of cuttings showing growth or browning. Temp Growth Browning 0C Jan. 28 May 2 May 10 Jan. 28 May 2 May 10 Grape — 5 100 100 100 0 0 0 — 10 100 100 30(100) o o o —is 100 100 20 ( so) 0 o o —20 100 40 (so) 20 o o 100 ~25 100 0 0 0 33 100 —30 50 (67) 0 0 0 100 100 —35 50 (67) O O O 100 100 -40 0 0 0 100 100 100 Cherry — 5 100 100 0 O — 10 100 70 (100) o 0 —15 60 (100) o o 100 —20 0 0 100 100 —25 O 0 100 100 Raspberry O 100 60 0 0 — 5 100 40 (60) o 0 —10 so (100) o (100) o 0 —1s 0 (100) o o 100 —20 0 0 100 100 —25 0 0 100 100 Strawberry O 100 100 0 0 — S O 0 100 100 — 10, 0 0 100 100 2Values in parentheses indicate percent survival. dehardening of 5°C between May 2 and May 10 in agreement with the browning test (Table 1). Although the range of specific conductivity seemed reasonably small for living tissue (Fig. 1), it varied considerably in dead tissue. Further, only a slight increase in specific conductivity occurred between living and dead tissue on May 2. However, values differed acceptably between living and dead tissue on May 10. Also, specific conductivity of living and dead tissue between May 2 and May 10 was significantly different. The reliability of this test was low as judged by its inconsistent performance. Analysis of hardiness by TTC reduction for raspberry proved unsatisfactory (Fig. 2), because consistent responses could not be obtained. Dead tissue, as indicated by growth, from stressed material collected on May 10, effectively reduced the TTC, but on May 2, the TTC was not reduced by similarly stressed tissue. The appearance of double freezing points in raspberry cane tissue was un- predictable, and sometimes indicated that the tissue was about 5°C hardier than was shown by the growth test (Fig. 3). Strawberry. The hardiness of strawberry crowns could be evaluated effectively by the tissue browning test (Table 1). No change in hardiness occurred between May 2 and May 10, and 0°C was the lowest survival temp. Values for TTC reduction and specific conductivity at the higher temperatures were variable (Figs. 1 and 2) between the dates even though there was no difference in hardiness, emphasizing the unpredictability of TTC reduction and specific conductivity responses in strawberry tissue. , Double freezing point curves were more reliable in strawberry than either specific conductivity or TTC reduction (Fig. 3). As expected, 2 exothenns appeared in curves from the living tissue. In dead tissue the “second” exotherrn appeared as a wide deflection in the curve, while there was no evidence of a first exotherm. This might be expected since a large portion of the crown consists of parenchyma (pith) tissue, with large intercellular spaces. These tissues contain a larger amount of water than do woody tissues, resulting in slower cooling. Discussion Even though growth and tissue browning were slow and qualitative, these tests were the most reliable. Although the labor needed is minimal, 1 to 2 weeks of incubation is necessary for the browning test, and up to 1 month for the growth test. These 2 factors coupled with the qualitative nature of the results are their major weaknesses. Results of both tests were in perfect agreement (Table l) and growth was used as the control for the other methods evaluated. This agreement between growth and browning is consistent with the findings of McLeester et al. (16) on dogwood. Both specific conductivity and TTC reduction would be suitable for evaluating grape stem hardiness, although specific conductivity was more critical. The unreliable performance of the specific conductivity test in cherry, raspberry, and strawberry due to excess variability might be explained in part Table 2. General summary of the advantages and disadvantages of viability tests for evaluation of woody plant hardiness. Test Advantages Disadvantages Species suited to test Growth and browning — Accurate in determining death —— Time required Cherry - Can be used as a control for Grape other tests - Slow Raspberry -— Unless data coded, can be Strawberry — Best for large samples biased Specific conductivity —- Variability usually small — Requires large amounts of Grape material per sample — More rapid than browning or — Slower than TTC reduction or growth multiple freezing point tests — Best test with few samples — Not practical for large when good standard response number of samples curve has been established TTC reduction -— Requires small amount of —- Considerable labor required Grape material per sample — Refinement of technique — Best to use when quantitative critical to success of test data necessary for larger — Variances large among sample sizes replicates — Not practical for large number of samples Multiple freezing points — Very rapid — Not quantitative Cherry — Responses tend to be the same; 2 exotherms when alive, 1 when dead — Accurate — Second freezing point may not Strawberry occur in same tissues —- Will occasionally indicate that a dead tissue is alive J. Amer. Soc. Hort. Sci. 98(4):325—-330. 1.973. 329 by the onset of metabolic activity in the stems during May. Wilner (23) has suggested that electrical conductivity varies according to changes in permeability of living cells due to seasonal periodicity in vegetative growth. Harris (7), however, claimed success with the specific conductivity test when his data on specific conductivity of strawberry crowns showed an inverse relationship with known field hardiness. The disappointing performance of the TTC test in general might be explained in part by: l) the need for specific techniques for specific tissues, and 2) cellular retention of the reductant NADPHz in varying amounts after the cell dies. 1n the species studied, the presence of a single exotherm always indicated death of the tissue. Two exothenns, however, were observed in raspberry even though the stem was dead. This was the most important weakness of the double freezing point ICSI. The continued drop in TTC reduction or rise in specific conductivity after the stem was killed is of interest. The cambium is necessary for whole plant survival. When this has been killed, the other tissues may still be alive. As low temp stress increases these tissues are ultimately killed. However, any cells which remain alive will still reduce the TTC dye. Likewise, as more tissue is killed, increasing amounts of electrolytes are released which increases specific conductivity. The viability tests compared in this study are listed and evaluated in Table 2. The data collected in this comparison were taken on dates during the dehardening period and on all sampled dates the rest period (physiological dormancy) had been satisfied. It is possible that a physiological condition such as rest could modify the relationships reported here. That possibility brings us to the central point to be derived from the study. The fact that a viability test has worked effectively on 1 plant under specific conditions is no guarantee that it will perform in a similar fashion on a different plant or even on the same plant under different conditions. Any researcher wishing to use a viability test should carefully determine specific responses on that, plant and compare it to a less quantitative but reliable test such as the growth test. In discussions with some scientists, it is apparent that there is growing use of an arbitrary amount of percent specific conductivity or percent 0D. for the TTC reduction evaluations as a breaking point for viability and death. The most frequently suggested is 50%. Our data show such usage to be without scientific merit. Further, to use these tests in such a way results in both tests losing their status as quantitative. 330 21 2. Darrow, G. M. 10. ll. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. . Harris, Literature Cited . Alden, J., and R. K. Hermann. 1971. Aspects of the cold-hardiness mechanism in plants. Bot. Rev. 37:37-142. 1966. The strawberry, history, breeding and physiology. Holt, Rinehart and Winston. 447 pages. . Dexter, S. T., W. E. Tottingham, and L. F. Graber. 1930. Preliminary results in measuring the hardiness of plants. Plant Physiol. 5:215-223. and _____. 1932. Investigations of the hardiness of plants by measurement of electrical conductivity. Plant Physiol. 7: 63-78. . Evert, D. R., and C. J. Weiser. 1971. Relationship of electrical conductance at two frequencies to cold injury and acclimation in Comus stolonifera Michx. Plant Physiol. 47:204-208. . Fuchigami, L. H., C. J. Weiser, and D. R. Evert. 1970. Induction of cold acclimation in Comus stolonifera Michx. Plant Physiol. 47298-103. R. E. 1970. Laboratory technique for assessing winter hardiness in strawberry (Fragaria x Ananassa Duch.). Can. J. Plant Sci. 50:249-255. . Howell, G. S., and C. J. Weiser. 1970. The environmental control of cold acclimation in apple. Plant Physiol. 45:390-394. ,and __ H1970 Fluctuations in the cold resistance of apple twigs during spring dehardening. J. Amer. Soc. Hort. Sci 95:190-192. Hudson, M. A., and D. B. Idle. 1962. The formation of ice in plant tissues. Planta 57 :718-730. Levitt, J. 1971. Responses of plants to environmental stresses. T. T. Kozlowski. ed. Academic Press. 697 p. Li, P., and C. J. Weiser. 1969.1ncreasing cold resistance of woody stems by artificial dehydration. Cryobiol. 6: 270. Loomis, G. P., R. A. Mecklenburg, and K. C. Sink. 1972. Factors influencing winter hardiness of flower buds and stems of evergreen azaleas. J. Amer. Soc. Hort. Sci. 97:124-127. Luyet, B. J., and P. M. Gehenio. 1937. The double freezing point of living tissues. Biodynamica 30:1-23. McLeester, R. C., C. J. Weiser, and T. C. Hall. 1968. Multiple freezing points as a test for viability of plant stems in the determination of frost hardiness. Plant Physiol 44:37-44. , and _. 1968. Seasonal variations in freezing curves of stem sections of Camus stolonifera Michx. Plant and Cell Physiol. 9: 807- 817. Parker, J. 1953. Criteria of life: some methods of measuring viability. Amer. Sci. 41:614-618. Steel, D. G., and J. H. Torrie. 1960. Principles and procedures of statistics. McGraw-Hill. p. 109-110. Steponkus, P. L., and F. O. Lanphear. 1967. Refinement of the triphenyl tetrazolium chloride method of determining cold injury. Plant Physiol. 42:1423-1426. , and . I969. The relationship of anthocyanin content to cold hardiness of Hedera helix. HortScience 4 :55-56. Weiser, C. J. 1970. Cold resistance and injury in woody plants. Science 169:1269-1278. Wilner, J. 1959. Note on an electrolytic procedure for differentiating between frost injury of roots and shoots in woody plants. Can. J. Plant Sci. 39:512-513. . 1960. Relative and absolute electrolytic conductance tests for frost hardiness of apple varieties. Can. J. Plant Sci. 40:6 30-637. J. Amer. Soc. Hort. Sci. 98(4):325—330. 1973. SECTION TWO EFFECT OF SITE ON COLD ACCLIMATION AND DEACCLIMATION IN Vitis labrusca L. var. Concord Vines EFFECT OF SITE ON COLD ACCLIMATION AND DEACCLIMATION IN Vitis labrusca L. var. Concord Vines1 Basil G. Stergios2 and Gordon S. Howell Michigan State University, East Lansing Abstract The effect of site on cold hardiness of Vitis labrusca L. var. Concord vines was investigated in south- western Michigan. Air temperatures from a low, poorly air-drained site were consistently lower than temperatures from a nearby high, well air-drained site.r Seasonal hardi- ness changes followed seasonal changes in air temperature. Living bark from low site vines acclimated faster and to a greater degree of hardiness than bark from high site vines. Both site, as well as compound (primary vs. secondary) bud polymorphy were important in determining bud hardiness differences. High site buds tended to be less hardy than 1Received for publication . Michigan Agricultural Experiment Station Journal ArtiCle No. 2Present address: Fundacion Servicio para el Agri- cultor (FUSAGRI), Calle 78, No. 46 - 21, Maracaibo, Vene- zuela S. A. Acknowledgments: we wish to express our appreciation to members of the National Grape Cooperative in Lawton, Michi- gan, Dr. Nelson Shaulis of the Geneva Experiment Station, and Stephen Stackhouse of Michigan State University for their help, guidance, and critical inputs. 22 23 low site buds, and secondary buds from either site tended to be hardier than primary buds. The early spring deaccli- mation status indicated that bud hardiness differences were due to site-induced differences in air temperature, while inherent differences between the primary and secondary bud were solely responsible for late spring bud hardiness differences. The two sites generated distinct temperature- induced microclimatics where differences in intracultivar adaptation was possible. Site-induced air temperatures, and bud differences appeared to interact to influence cold hardiness of Concord grape vines during acclimation and deacclimation. Concord grape vines apparently adapted to lower fall, winter, and spring air temperatures through exposure. Introduction Freezing damage has been a problem of major eco- nomic significance to native vegetation and crop plants (1, 28). Parker (15) stated that the reason cold became so acutely limiting to the success of plants in some areas was not only the excess of out-going radiation over incom- ing but also the fact that cold air tended to remain near the ground and produce a relatively static situation in which local temperatures fall below the surrounding levels. The existence of this phenomenon suggested that adaptation to local low temperature at low sites might have played a role in determining the cold hardiness of a cultivar. 24 Even though low temperature was estimated to be the most significant environmental factor causing direct plant injury in cold climates (3), quite severe injury from cold did not necessarily limit plant establishment and distribution in regions of annual subfreezing weather. (24). Once the initial acclimation phase in hardy woody plants was complete, the degree of freezing resistance of a species in winter may differ considerably depending on the air temperature at which the plants were wintering (20). Generally, increasing cold tolerance to decreasing winter temperatures has been recognized as an adaptive feature of the plant (13). It has been commonly accepted among viticulturists that site selection was the most critical of vineyard establishment (4, 7, 21, 22, 23), in order to insure that there may be adequate solar radiation, drainage of poten- tially injurious cold air, acceptable soil type and water drainage (7, 21). weak air drainage generates lower minimum air temperatures (5). Topographic depressions and an opening in a young pine stand were the sites of the lowest minimum temperatures. Minimum night temper- " atures during the spring near the soil surface were -90°C on a lodgepole pine flat site, and -6°C on an adjacent ponderosa pine slope in eastern Oregon (2). Locating a grape vineyard on sloping ground has been considered advantageous because these areas had higher night 25 temperatures and were less likely to have a freeze when- ever the cold air drained onto adjacent low-lying areas (4). Vineyard elevation, as it relates to air drainage, is recognized by scientists and growers to be important for frost protection. In the absence of good air drainage, adaptation of canes and buds to tolerate local lower air temperature becomes more important (9, 10, 24). This study was initiated to investigate the effect of site-induced air temperature on the acclimation and deacclimation patterns in Concord (Vitis labrusca L.) grape vines. Methods and Materials The Study Area Two 4.9 ha Concord grape vineyards located in Van Buren County, Michigan (T3S, R13W, Sec. 32) were selected for the study. The first vineyard is located on a high (elev. approx. 277 m above sea level), well air-drained site. It is surrounded by other vineyards situated to the east and south, and open fields to the north. The second vineyard is located on a low (elev. approx. 256 m above sea level), poorly air-drained site directly west of the first site. It occupies a depression surrounded on the south and west by other vineyards and on the north by open fields. The two study sites are approximately 210 m apart, separated by a 6° slope containing a tart cherry (Prunus cerasus L.) orchard. The site topography is 26 fairly homogeneous while the low site tapers off gently into a pocket at the southwest corner. The grape vines on both sites were planted in 1904 on Plainfield sand (29), and have since undergone inter- mittant renewal. They were planted in rows of 48 vines, spaced at 2.5 m, with 2.8 m between the rows. Sampling Procedures Samples were taken from 36 vines selected for uni- formity in 1970 and balance (30 + 10) cane-pruned. A vine was balance pruned when 30 buds were left for the first pound of current cane growth removed (prunings), and 10 more buds left for each additional pound of removed prunings (16). The vines were trained to an umbrella kniffen system and constituted a 2.5 ha experimental plot at each site. Hardiness evaluations were made periodically during the fall and spring of 1971-1973. Single node stem sections, cut in the mid-point of the internode, were made from the mid-portion of 10 to 20 node mature canes chosen for their maturity as determined by cane color and diameter (16). The single node samples were sealed in small plastic bags and were transported within two hours to the laboratory without elevating their temperature. Bark (cambium and phloem) and compound bud samples were then evaluated for hardiness, which was determined as described below. 27 Hardiness and Air Temperature Measurements Hardiness was determined on each sampling date by subjecting the material to a controlled freezing stress as described by Howell and Weiser (11). Test samples from the field were immediately labeled, wrapped in aluminum foil, and placed into a series of vacuum flasks which were then cooled in a controlled temperature freezer at approxi- mately 5°C per hour. Each test sample consisted of 3 observations from 18 vines. A 26-gauge copper-constantan thermocouple was inserted in the pith of one cane section in each flask to monitor sample temperature. Previous unpublished data indicate that this freezing rate allowed sufficient time for all canes to equilibrate to the same temperature as the indicator cane. Flasks were removed from the freezer at 5°C intervals and allowed to warm in the flasks to ambient (approx. 21°C) temperature. Bark, primary and secondary buds were evaluated for viability with the browning test (25). Bark hardiness was recorded as the lowest survival temperature. With the 5°C intervals no differences among replicates were observed, and therefore each point on a figure represents both the mean and the observed range. Primary and secondary bud hardiness was determined using graphic methods to determine the 50% survival rate (T50; 18, 19). The buds were judged alive when they were all green and dead when at least their center portions were browned (26). 28 Daily maximum and minimum air temperatures for the general study area were recorded during spring and September, 1971 from a nearby weather station (14). Beginning in November, 1971 maximum and minimum air temperatures were recorded daily from thermograph recorders in the vineyards. They were enclosed in conventional weather boxes and placed about 1.5 m from the ground at the highest and lowest point in each experimental plot. Air temperature readings from both recorders were averaged together at each site, and the resulting mean maximum and minimum values are given in Figures 1 - 4. Weekly mean maximum and minimum air temperatures and season minimal air temperatures for both sites are given in Table 1. Results Figures 1 - 4 show site differences in the seasonal hardiness changes of living bark and buds of Concord grape vines from 1971 to 1973. These hardiness patterns were associated with seasonal changes in air temperature (Fig. 1 - 4), and were generally similar to those described for peach buds (16, 17), Cornus stoloniferea Michx. (26), apple (10, ll, 12), and Forsythia intermedia Zabel (8). Site differences in air temperature were also evident. Seasonal mean maximum weekly temperatures were generally higher on the high site and minimum temperatures consistently lower on the low site (Table 1). Seasonal 29 minimum air temperatures were also always lower on the low site (Table 1), with a four-season grand mean minimum 0f -1508OC0 Acclimation Bark of low site vines had attained 10°C more hardiness than high site vines by mid-fall, 1971. By mid- December, the vines were at maximum hardinesses. At this stage low site bark was 5°C more hardy than high site bark (Fig. 1). Results indicate that site, as well as compound bud polymorphy were important in determining bud hardiness dif- ferences. Both primary and secondary buds from high site vines were always less hardy than those from low site vines during fall and early winter acclimation in 1971 (Fig. 1). By mid-season, 1971, it became clear that primary buds ‘were less hardy than secondary buds on both sites, with buds on the low site being hardier. In early winter, 1971, the primary buds were about as hardy as the secondary buds at each site, but high site buds were still less hardy than low site buds. In 1972 (Fig. 2) bark hardiness followed the same general pattern of acclimation as in 1971 (Fig. 1). In the early fall of 1972 (Fig. 2) the bark of low site vines had attained 5°C more hardiness than high site vines. By nudrseason, high site bark had attained the same hardiness 30 as low site bark (Fig. 2). Low site bark was again 5°C more hardy than high site bark by early winter (Fig. 2). Bud hardiness differences between sites were less ' evident in 1972. By the middle of the hardening season, however, both primary and secondary buds were less hardy on the high site than their counterparts on the low site. Secondary buds were always more hardy than primary buds through the 1972 fall season regardless of site (Fig. 2). Bark from low site vines was 10°C more hardy than high site bark by mid-acclimation 1971 (Fig. l), but nearly the same hardiness as high site bark was during the same period in 1972. Bark from both sites had similar hardiness in early winter for both 1971 and 1972 (Figs. 1 and 2). Bark from both sites acclimated at a faster rate than the buds and continued to harden longer. The buds reached a maximum hardiness in November, after which the hardiness normally leveled off (Figs. 1 and 2). However, the hardiness decreased when there was an early winter thaw (Fig. 1). That observation agreed with observations :made by Proebsting (18) on Elberta peach buds. Deacclimation Bark tissue hardiness changed with fluctuating air temperatures in the spring of 1971 (Fig. 3). Bark from high site vines remained 5°C less hardy than bark from low site vines until mid-May, when air temperature 31 minimums were above freezing. At that time the bark attained equal hardiness on each site (Fig. 3). As was the case during acclimation, both site- induced air temperatures and bud polymorphy appeared to influence deacclimation as they did acclimation. Site- induced bud hardiness differences were evident during early spring deacclimation. High site buds were less hardy than low site buds throughout the deacclimation period in 1971, and, regardless of site, primary buds were always less hardy than secondary buds (Fig. 3). With warmer air temperature minimums in 1972 and 1973, bark tissue from both sites dehardened faster, and reached the same hardiness level earlier in the season (Figs. 2 and 4). In an apparent response to sudden increase in air temperature (Fig. 4), high site bark dehardened more rapidly than low site bark in 1972. Primary buds from high site vines were less hardy during deacclimation than low site primaries in 1972 (Fig 4). The same relationship held for secondary buds,, and the difference remained even after the primary buds had broken in late April. The deacclimation pattern of primary buds in 1973 (Fig. 2) was similar to that in 1972, and in 1973 secondary bud dehardening was as in 1971. IHowever, differences between the hardiness of secondary Ibuds from the two sites were smaller in 1973. 32 High late spring air temperatures hastened deaccli- mation to the point where site differences were no longer important. In general, secondary buds from both sites remained hardier than the primary buds (Figs. 1, 2, 3) during the dehardening period. In 1971 and 1972, when hardiness measurements were made later in the season than in 1973, primary buds had completely dehardened and begun to grow. Secondary buds remained dormant and retained hardiness during the same measurement period. Discussion Air temperatures in the low site would perhaps have been lower than indicated if it were not for the cherry orchard barrier between the two sites. Dethier and Shaulis (4) have pointed out that a dense woods above the vineyard can divert and/or reduce the flow of air down-slope into the vineyard, thus less of the warmer air is displaced upward. Nevertheless, air temperatures in the low site were consistently lower than in the high site. This would create a distinct microclimate allowing for greater vine adaptation to lower temperatures and greater vine hardiness. This was reasonable in the light of Parker's statement that, "WOody plants, as a result of their life-form, must grow year after year in the same location and they must, therefore, be able to withstand great temperature variations in some climates. Since these sessile organisms survive 33 only under conditions favorable to them, they become standing indicators of the environmental conditions to any particular place" (15). Sakai (20) found that the maximum and duration of freezing resistance of Salix babylonica L. Twigs differed considerably depending on the temperature regime in a given locality. Smithberg and weiser (25) and Flint (6) found that plants from semi- tropical origins hardened more slowly than plants from temperate origins, and so were less hardy at specific times. However, all eventually hardened sufficiently to avoid low temperature injury. Even though Concord grape vines responded to lower temperatures of the sites by developing greater hardiness, the risk of cold injury to low site plants was still great due to temperature fluctuations in early fall and late spring. Injury could have resulted to even the most hardy vines because their lowest survival temperatures were still higher than the lowest air temperatures. The general effects of air temperature on harden- ing and dehardening, as documented earlier (8, 9, 10, ll, 12) have been supported by this study. Air temperature, site, and polymorphic differences between primary and secondary buds appear to simultaneously affect hardiness in Concord grape vines. Thus in early spring when air temperature was still low enough to maintain hardiness, site differences in bud hardiness were apparent. In late 34 spring, however, air temperatures were high enough to permit growth of the more dominant primary bud in both sites while the secondary bud in both sites did not grow and remained hardy. It was not possible to explain intra- site hardiness differences between the primary and secondary buds which occur consistently throughout accli- mation and deacclimation. They could have been due to hormonal or other regulation of certain mechanisms favor- ing primary bud ontogeny and maturation. The strong apical dominance of grapevines may have been operating in the dormant bud. Primary and secondary bud hardiness and pro- ductivity differences in Concord grapes have already been recognized (17, 26). Conclusions Air temperatures in a low, poorly air-drained Concord grape vineyard were consistently lower than in a high, well air-drained vineyard site. High and low vine- yard sites may generate distinct temperature-induced microclimatic environments where differences in intra- cultivar hardiness differences were possible. Changes in bark and bud hardiness were related to air temperature changes. Generally, bark hardiness was least modified by sudden temperature changes; secondary buds more affected and primary buds most susceptible. 35 Concord grape vines growing on low sites produced bark and primary and secondary buds which were hardier during acclimation and deacclimation than bark and buds from high site vines. In a given site, living bark was hardier than secondary buds which were generally hardier than primary buds. The high site microclimate induced greater bud hardiness fluctuation than did the low site microclimate. Thus site-induced air temperature and bud dif- ferences collectively influenced hardiness patterns in Concord grape vines during the periods of acclimation and deacclimation investigated. 36 Table 1. Weekly mean maximum (max.) and minimum (min.) air temperatures (°C) for a high (H), well air-drained and a nearby low (L), poorly air-drained Concord grape vineyard in Van Buren Co., Michigan from fall, 1971 to spring, 1973. Date H-max. L-max. H-min. L-min. 1971 Nov. 1-5 14.0 12.5 0 0 " 6-10 2.5 2.0 -5.5 -6.0 DeC. 1-5 1.0 1.0 -700 -800 " 6-11 6.0 7.5 -3.0 -0.5 Fall seasonal minimum -9.0 -10.0 1972 .Mar. 21-25 4.0 4.0 -8.0 -9.0 ' 26-31 5.0 5.0 -5.5 -6.0 " 8-14 13.0 13.5 -2.5 -3.0 " 15-21 16.5 16.0 3.0 2.0 " 22-30 12.5 13.0 0.5 0 Spring seasonal minimum -14.0 -20.0 Oct. 5-11 15.0 15.5 3.5 4.5 " 12-18 9.5 9.5 -1.5 -l.5 “ 19-25 11.5 9.5 3.0 0.5 NOV. 15-21 105 1.0 -700 -700 II 22-30 2.0 1.5 -305 -505 Dec. 5-11 -4.5 -4.5 -10.5 -12.0 " 12-18 -4.5 -4.5 -9.5 -ll.5 " 19-25 0.5 0 -2.0 -3.5 Fall seasonal minimum -17.0 -19.0 1973 Mar. 21-25 5.0 4.0 -8.5 -9.0 " 26-31 12.5 11.0 -3.5 -2.5 Apr. 1-7 12.5 11.5 3.5 2.5 " 8-14 7.0 6.0 -5.5 -5.0 " 15-20 19.0 19.5 5.0 7.0 Spring seasonal minimum -13.0 -l4.0 Fig. l. 37 Acclimation of living bark, and of primary and secondary buds from balance pruned Concord grape vines in a high (elev. 277 m), well air-drained site and a low (elev. 256 m), poorly air-drained site in 1971 in Van Buren Co., Michigan. Symbols indicate lowest survival temperatures (expressed as T for buds). Daily maximum and minimum 50 temperatures are recorded for the general vicinity, and within experimental plots for November and December. TEMP ERATURE (’C) 38 I“ I O -ro< -..J «at «94 '30‘ ~———~qufxr (no row «to available) DOD —- U. .1! HI. "n“ In“ I"! ‘ ------- I." I" an. > Low It" u IIPTIIIII 067ml ‘ Milan Iu' Lou 0m I D . 7 3 a“? i a "VIU'I O'C‘I". D A Y 8 0 My lu- mn am A "In." ou- mg. 0". . 00mm 0.1- Low em D Lmu Ion . I“. In. I this. lul- Lou um Figure l Fig. 2. 39 Acclimation and deacclimation of living bark, and of primary and secondary buds from balance pruned Concord grape vines in a high (elev. 277 m), well air-drained site and a low (elev. 256 m), poorly air-drained site during 1971 and 1972 in Van Buren Co., Michigan. Symbols indicate lowest survival temperatures (expressed as T50 for buds). Daily maximum and minimum experimen- tal plot air temperatures are recorded. TFuDF‘RATURF (°C) 40 n . .lt... a u .Hv 48 D u I Kit; n m m m m D I u .n. n I ! ... .1. s . .. u n V- .m m n um D I A m M w 1 . a m" o m m u «L . . M o A "I V Mn . ......¢u m m AV mm a n M .a " am 8- mm m m m u 0 A . .......r...nn..4 I n m o m o w .0; weap<¢uL2up Figure 2 Fig. 3. 41 Deacclimation of living bark, and of primary and secondary buds from balance pruned Concord grape vines in a high (elev. 277 m), well air- drained site and a low (elev. 256 m), poorly air- drained site in Van Buren Co., Michigan in 1972. Symbols indicate lowest survival temperatures (expressed as T for buds). Daily maximum and 50 minimum temperatures for the general vicinity are recorded. .. 42 .09. ugkdcutlu h m mun In It yu «an an 2 an“ m. n map P D I van num a I .u mm" mu «-mu on .t. gnu . u o I .mm 0A- l A0 ‘7 t u. s mm Y T u A n on a un- u «um . . 3.. o u." .C. u "um I . AX. 1.." mm». a «mm N OIL AX. 1...... can 91".“ o. u . um u w u m . . - - o . - .u a a a Figure 3 Fig. 4. ~temperatures (expressed as T 43 Deacclimation of living bark, and of primary and secondary buds from balance pruned Concord grape vines in a high (elev. 277 m), well air- drained site and a low (elev. 256 m), poorly air-drained site in 1973 in Van Buren Co., Michigan. Symbols indicate lowest survival 50 for buds). Daily maximum and minimum experimental plot air temperatures are recorded. 44 ..u u -. mum w mm um .u VIM L U. "0 Mr 1.. “Tm” 2 Ir . um "M: 3333 no no. mm 3 I on m I T ' ‘ - ' M D . o u . . Z .1. a .... .00. w¢3k<¢wt1wfi v A'III. DAYS Figure 4 10. LITERATURE CITED Alden, J. and R. R. Hermann. 1971. A5pects of the cold hardiness mechanism in plants. Bot. Rev. 37: 37-142. Bernsten, C. M. 1967. Relative low temperature tolerance of lodgepole and ponderosa pine seed- lings. Ph.D. Thesis. Oregon State University, Corvallis. 158 pp. Compana, R. 1964. Non-infectious tree diseases, Part 1. Effect of cold injury and freezing. weed & Turf 3(8): 10-11, 22-23. Dethier, B. E. and N. Shaulis. 1964. Minimizing the hazard of cold in New York vineyards. New York Agr. Expt. Sta. Bul. No. 1127. 7 pp. Duffy, P. J. B. and J. W. Fraser. 1963. Local frost occurrences in eastern Ontario woodlands. Can. Dept. Forestry Publ. 1029. 24 pp. Flint, H. L. 1972. Cold hardiness of twigs of Quercus rubra L. as a function of geographic origin. Ecology 53(6): 1163-1170. Haeseler, C. W. 1970. Climatic factors in the potential for wine grape production in several areas of Pennsylvania. Penn. State Univ. Agr. Expt. Sta. Prog. Report No. 303. 12 pp. Hamilton, D. F. 1973. Factors influencing hardening and rehardening of Forsythia intermedia stems. J. Amer. Soc. Hort. Sci. 98 (2): 22I- 223. Howell, G. S. and C. J. Weiser. 1968. What makes plants hardy. Horticulture 46: 19-45. and . 1970. The environmental control of cold acclimation in apple. Plant physiol. 45: 390-394. 45 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 46 Howell, G. S. and C. J. Weiser. 1970. Fluctuations in the cold resistance of apple twigs during spring dehardening. J. Amer. Soc. Hort. Sci. 95(2): 190-192. Ketchie, D. O. and C. H. Beeman. 1973. Cold accli- mation in 'Red Delicious' apple trees under natural conditions during four winters. J. Amer. Soc. Hort. Sci. 98(3): 257-261. Lorenzetti, F., B. F. Tyler, J. P. COOper, and E. L. Breeze. 1971. Cold tolerance and winter hardiness in Lolium erenn . 1. Development of screening techniques for cold tolerance and survey of geo- graphical variation. J. Agri. Sci., 76: 199-209. Michigan Climatological Data. A U.S. Dept. of Commerce Pub. 86(2-5). Feb.-May, 1971; 86(9). Sept., 1971. Parker, J. 1963. Cold resistance in woody plants. Bot. Rev. 29(2): 123-201. Partridge, N. L. 1925. The fruiting habits and pruning of the Concord grape. Mich. State Agr. Expt. Sta. Bul. No. 69. 39 pp. Pogosyan, R. S. and A. Sakai. 1969. Freezing resis- tance in grape vines. Hokkaido Univ., Low Temp. Sci. Ser. B. 27: 125-144. Proebsting, E. L. 1963. The role of air temperatures and bud development in determining hardiness of dormant Elberta peach fruit buds. Proc. Amer. Soc. Hort. Sci. 83: 259-269. and H. H. Mills. 1961. Loss of hardiness 5y peach fruit buds as related to their morphologi- cal development during the pre-bloom and bloom period. Proc. Amer. Soc. Hort. Sci. 78: 104-110. Sakai, A. 1970. Freezing resistance in willows from different climates. Ecology 51(2): 487-491. Shaulis, N. 1970. New York site selection for wine grapes. Proc. New York State Hort. Soc. 115: 288-294. . 1971. Vine hardiness a part of the proBIem of hardiness to cold in New York vineyards. Proc. New York State Hort. Soc. 116: 158-167. 23. 24. 25. 26. 27. 28. 29. 47 Shaulis, N., J. Einset, and A. B. Pack. 1968. Growing cold-tender grape varieties in New York. New York Agri. Exper. Sta. Bul. No. 821. 16 pp. Smithberg, M. H. and C. J. Weiser. 1968. Patterns of variation among climatic races of red-osier dogwood. Ecology 49(3): 495-505. Stergios, B. G. and G. S. Howell. 1972. Evaluation of viability tests for cold stressed plants. J. Amer. Soc. Hort. Sci. 98(4): 325-330. and . 1974. In situ destruction of dormant Concord grape primary Buds without secondary bud kill. HortScience 9(2): 120-122. Van Huystee, R. B., C. J. Weiser and P. J. 11. 1967. Cold acclimation in Cornus stolonifera and natural and controlled photoperiod and temperature. Bot. Gaz. 128: 200-205. Weiser, C. J. 1970. Cold resistance and injury in woody plants. Science 169: 1269-1278. Wildermuth, R., J. A. Kerr, F. w. Trull, J. w. Stack. 1926. Soil survey of Van Buren Co., Michigan. U.S. Dept. of Agriculture, Bureau of Soils. 42 pp. SECTION THREE EFFECTS OF DEFOLIATION, TRELLIS HEIGHT, AND CROPPING STRESS ON THE COLD HARDINESS OF Vitis labrusca L. var. Concord Vines EFFECTS OF DEFOLIATION, TRELLIS HEIGHT, AND CROPPING STRESS ON THE COLD HARDINESS OF Vitis labrusca L. var. Concord Vinesl Basil G. Stergios2 and Gordon S. Howell Michigan State University, East Lansing Abstract Cold hardiness of the bark and compound buds of culturally stressed Concord grape (Vitis labrusca L.) vines was investigated in southwestern Michigan. Results showed that defoliation, pruning severity, and cluster thinning influenced bark and bud hardiness. The effect of trellis height on bark hardiness was inconclusive but some increased hardiness was noted for low trellis buds. Complete defoliation by hand in August resulted in delayed acclimation in the fall and more rapid deacclimation in the spring. Effects of defoliation on bark and bud 1Received for publication . Michigan Agricultural Experiment Station Journal Article No. 2Present address: Fundacion Servicio para el .Agricultor (FUSAGRI), Calle 78, No. 46 - 21, Maracaibo, Venezuela. .Acknowledgments: We wish to express our appreciation to members of the National Grape COOperative in Lawton, Michigan, Dr. Nelson Shaulis of the Geneva Experiment Station, and Stephen Stackhouse of Michigan State Uni- versity for their help, guidance, and critical inputs. 48 49 hardiness were more pronounced during the second year of treatment. Pruning severity was the most important factor influencing bark and bud hardiness in the nondefoliated plants. Field observations emphasized the importance of balance (30 + 10) pruning, as Opposed to light (60 + 10) pruning for greater hardiness. Cluster thinning increased hardiness levels depressed by 60 + 10 pruning particularly when vines were defoliated. The greater sensitivity of under-pruned vines seemed to be a result of the over- production of fruit. The tertiary bud was usually as hardy or slightly hardier than the secondary bud with most treatments. Introduction Woody plants in a dormant condition are injured by low temperature to some extent in most winters (28), and also when early fall or Spring low temperature fluc- tuations occur (10, 28, 29, 31, 32, 44). Excessively low temperatures in late fall, early winter or in the spring have been associated with cold injury in grape plants (2, 3, 26, 27, 44). Low temperature stress was determined to be a limiting factor in grape Production in the states of Washington (3), New York (4, 34, 37), Pennsylvania (9), and Michigan (44). Economic losses due to low temperature have been extensive in Michigan where average Concord (Vitis labrusca L.) grape production 50 for the past 5 years was 6046 kg/ha (19). Production in milder New York (20, 21) and Washington (6) for the same period was about 10,783 kg/ha and 16,135 kg/ha respectively. Olien (22) pointed out that winter hardiness was a complex plant property involving many interacting factors and many types of stress. Such stress could not only be environmentally induced (11, 32, 33, 44), but also cul- turally induced (5, 12, 36, 37). This study was initiated to investigate the effects of hand defoliation, pruning severity, cluster thinning, and trellis height on the cold hardiness of Concord grape vines. Materials and Methods The Study Area A 4.9 ha Concord grape vineyard located in Van Buren County, Michigan (T38, R13W, Sec. 32) was selected for the study. It had a high (elev. approx. 277 m above sea level), well air-drained site with other vineyards situated to the east and south, open fields to the north and a tart cherry (Prunus cerasus L.) orchard to the west 'which slopes 6° downward for 210 m away from the study area. The topography of the study area is fairly homo- geneous. The grape vines were planted in 1904 on Plainfield sand (47), and-have since undergone intermittant renewal. They were planted in rows of 48 vines, spaced at 2.5 m, 51 with 2.8 m between the rows. Two additional wires (high trellis), one about 40 cm above the other were placed directly above the top of the original trellis for the entire length of each row. The space from the top of the original trellis to the bottom additional wire was 1.5 m. The top of the original trellis was 2 m above the ground. The vines of each plant were trained onto the high trellis during the 1971 growing season by extending the trunk vertically from the low originally trellised growth. No shoots were allowed to grow in the 1.5 m space between the high and the low trellis. Experimental Design and Sampling Procedures Samples were taken from both the high and low trellis positions of 288 vines selected initially for uniformity in 1970. A11 vines were trained to an umbrella kniffen system and constituted a 2.5 ha observational plot. The plot was completely randomized and consisted of 8 treatments, with 36 vines per treatment available for sampling. One half of the treatment vines were sampled for fall hardiness, and the other half were sampled in the spring. Each treatment consisted of a combination of the three variables: defoliation, pruning severity, and cluster thinning, and are ranked in order from the least stress to the most stress as follows: 52 Not defoliated, 30 + 10 pruned, thinned Not defoliated, 60 + 10 pruned, thinned Not defoliated, 30 + 10 pruned, not thinned Not defoliated, 60 + 10 pruned, not thinned Defoliated, 30 + 10 pruned, thinned Defoliated, 60 + 10 pruned, thinned Defoliated, 30 + 10 pruned, not thinned Defoliated, 60 + 10 pruned, not thinned The vines were either balance pruned at 30 + 10 (17, 23) or pruned less severely at 60 + 10 during the mid- winter of 1971, 1972, and 1973. A vine was balance pruned when 30 buds were left for the first pound of current season's cane growth (prunings) removed and 10 more buds were left for each additional pound of prunings (17, 23). Designated vines were hand cluster thinned to one cluster per shoot at anthesis (around the second week of June in 1971 and 1972). Designated vines were hand defoliated (all the leaves were removed) at verasion (initiation of fruit coloring) which occurred during the third to fourth week of August in 1971, 1972, and 1973. Hardiness evaluations were made periodically during the fall and spring of 1971-1973. Single node cane sections, cut in the mid-point of the internode, were made from the mid-portion of 10 to 20 node mature canes chosen for maturity as determined by cane color 53 and diameter (1, 23). The single-node samples were sealed in small plastic bags and were transported within two hours to the laboratory without elevating their temper- ature. The samples were then evaluated for hardiness as described below. Hardiness Measurements Hardiness was determined on each sampling date by subjecting the material to a controlled freezing stress (10, 42). Test samples from the field were immediately labeled, wrapped in aluminum foil, and placed into a series of vacuum flasks which were then cooled in a con- trolled temperature freezer at approximately 5°C per hour. Each test sample consisted of one observation from each of the 18 treatment vines. A 26-gauge copper-constantan thermocouple was inserted in the pith of one cane section in each flask to monitor sample temperature. Previous unpublished data indicate that this freezing rate allowed sufficient time for all canes to equilibrate to the same temperature as the indicator cane. Flasks were removed from the freezer at 5°C intervals and allowed to warm in the flasks to room (approx. 21°C) temperature. Bark, primary and secondary buds were tested for viability with the browning test (42). With the 5°C intervals, no dif- ferences among replicates were observed for bark hardiness, and therefore each point on a figure represents both the mean and the observed range. Bark hardiness was recorded 54 as the lowest survival temperature. Primary and secondary bud hardiness was determined with graphic methods to determine the temperature at which there was 50% survival (T50; 29, 30). The buds were judged alive when they were all green, and dead when their center portions browned (43). The term l'cane hardiness," as used in this paper, will be synonomous with bark hardiness. Results Seasonal descriptive differences in the hardiness of Concord bark and buds which were culturally stressed are shown in Figures 1 - 4, and are discussed below. Bark Hardiness Defoliation had the greatest effect on bark hardi- ness during both seasons evaluated (Figs. 1 and 2). Leaf removal, while causing only a moderate hardiness reduction during the first season, markedly reduced bark hardiness during the second season (Fig. 2). Hardiness losses resulting from cropping stress (light pruning seventy and no cluster thinning) and trellising were not evident during the second season. In December and March of the first season, however, light pruning of defoliated vines reduced high trellis bark hardiness (Fig. 1, Treatments G and H).A During earlywacclimation (October 2), high trellis bark of defoliated, balance pruned vines was as hardy as bark from nondefoliated vines (Fig. 1). Bark acclimation was 55 favored by the high trellis position in October of the first season (Fig. l). The high trellis position also favored bark acclimation of both nondefoliated balance pruned vines in November, and nondefoliated vines stressed by light pruning on April 29. Low trellising favored bark hardiness only during the first season (Fig. l) but the results were inconclusive. High trellising favored bark hardiness in December (Fig. l) for some treatments (A, B, D). Primary Bud Hardiness Since the buds (particularly the primary buds) are more responsive to factors influencing hardiness than the bark (44), even small changes and fluctuations in bud hardiness can be a valid manifestation of treatment effect. Defoliation had a pronounced effect during both seasons as it did with the bark (Figs. 1 and 2). However, hardi- ness differences resulting from trellising and cropping stress were not as obvious during the second cold season as they were during the first. Light pruning generally retarded bud hardiness on foliated plants in October 1971. However, hardiness was greater on plants with less fruiting stress (thinned) whether or not they had leaves (Treatments B, D, and F). Trellising and cropping stress did not appear to have an appreciable affect on bud hardiness in October of the 56 second season. Bud acclimation for all treatments had proceeded further by November, and hardiness was somewhat retarded as the treatment-stresses were increased (Fig. 1, Treatments A to H). Cropping stress did not influence hardiness in November of the next season and trellis height did not influence bud hardiness during October and November of either season. During the December thaw in 1971, high trellis buds dehardened more than the low trellis buds (Fig. 1). Low trellis buds were hardiest on foliated, balance pruned vines. When the buds were at maximum hardiness in December of 1972, foliated canes with less fruiting stress had superior bud hardiness (Fig. 2, Treatment B) when they were balance pruned. As dehardening began in late March of the first season evaluated, buds on balance pruned, foliated canes with least fruiting stress (Treatment B) were the hardiest. Buds of defoliated canes lost hardiness but, when they ‘were balanced pruned (Treatments E and F), low trellis buds remained hardy. Both high and low trellis buds lost less hardiness when cluster thinned (Treatment H) than ‘when fruit-stressed (Treatment G). In March of the second season, high trellis bud hardiness was favored by balance pruning on foliated vines (Treatments A and B). Cluster 57 thinning delayed bud dehardening on lightly pruned, foliated canes and on balance pruned, defoliated canes (Treatments D and F). The buds had dehardened considerably by April 15 of the first season. Buds which were on low trellis, balance pruned canes retained the most hardiness (Treatments A and B). Low trellis bud dehardening was also retarded more when cluster thinning was combined with balance pruning (Treatment B). Buds from defoliated canes were killed between April 15 and April 29. In April of the second season (Fig. 2), the buds showed continued deharden- ing, but there were no apparent hardiness differences caused by the eight treatment combinations. Secondary Bud Hardiness Observations indicated that cultural practice treatments affected secondary bud hardiness during the 1971-1972, and 1972-1973 acclimation and deacclimation periods (Figs. 3 and 4). Defoliation had a greater effect on secondary bud hardiness than any other treatment during both seasons evaluated. This effect was more pronounced during the second cold season than during the first. Bud hardiness was favored by the low trellis position in October of the first season and also, to a lesser extent, in October Cfi'the second season (Fig. 4, Treatments A to D). Light 58 pruning retarded bud acclimation on foliated, high trellis canes in October of the first season, and on all foliated trellising in October of the second season (Fig. 3, Treatments C and D). Buds from all treatments had acclimated further in both 1971 and 1972 by November. Hardiness differences were slight in 1971. Cluster thinning enhanced the accli- mation of defoliated buds when they were located on balance pruned vines (Treatment F). Balance pruning, and to a lesser degree cluster thinning, increased bud hardiness on foliated canes in 1972. High trellis bud hardiness was reduced in most of the treatments during the December thaw in 1971 (Fig. 3). The buds attained maximum hardi- ness in December of the second, and only leaf removal was observed to reduce hardiness (Fig. 4). High trellis buds (Treatments E - H) and fruit- stressed low trellis buds (Treatment G) from the defoliated canes had begun to deacclimate by late March of the first season. Low trellis buds from balance pruned, cluster thinned canes (Treatment B) retained the most hardiness. Buds from leafed canes showed delayed deacclimation in March of the second season (Fig. 4, Treatments A - D). As in the first cold season, buds from Treatment B retained greatest hardiness during initial deacclimation. On April 15 in both 1972 and 1973, buds from the balance pruned, foliated treatments were hardiest. Balance 59 pruning enhanced low trellis bud hardiness among the defoliated treatments on April 15 of the first season. Buds from defoliated canes had either completely dehardened, or were dead by April 29 (Fig. 3), except those which were cluster thinned (Treatments F and H). Buds from balance pruned, foliated canes remained the hardiest. When canes were lightly pruned, low trellis buds retained more hardi- ness than high trellis buds (Treatments C and D). Tertiary Bud Hardiness Acclimation and deacclimation observations of ter- tiary buds during 1971-72 and 1972-73 are given in Figures 3 and 4. They indicate that tertiary bud hardiness was affected by the cultural stress treatments in a manner similar to the secondary bud responses. The tertiary bud was usually just as hardy or occasionally hardier than the secondary bud, but specific differences appear too small for practical comparison. Discussion Recent research has implicated leaves as the source of substances which promote hardiness in deciduous woody plants (12, 13, 39). It has been suggested that sub- stances act as growth (hardiness) regulators (7, ll, 14, 39) and as energy sources (7, 8, 12, l6, 18, 33, 39, 41) on being translocated from the leaves to the woody tissues and buds (7, 14, 15, 40). 60 Whether grape leaves produce growth regulator type hardiness promoters is unknown. However, the importance of foliage for good wood maturity and hardiness has been recognized as a factor in grape culture (18, 35, 38). The defoliated and foliated high-trellis treatments investigated during the study represent extremes of maxi- mum and minimum leaf area available for manufacturing hardiness promoting substances whether regulatory or metabolic in nature. Regardless of mode of action, observations recorded in this paper indicate that the combined cultural stresses of leaf area loss, light pruning, and nonthinning delayed fall acclimation and caused early loss of hardiness in Concord grape vines in the spring. Defoliation Summer leaf removal at verasion was effective in inhibiting cold acclimation of Concord grape canes and buds in the fall, and hastening deacclimation of canes and buds in the spring. Similar results were reported by Howell and Stackhouse (12) as a result of early leaf loss from tart cherry (Prunus cerasus L.) trees. Fuchigami gt 31. (7) reported that container grown Cornus stolonifera Michx. plants which were completely defoliated on .August 8 failed to acclimate and were dead by November 14 when exposed to -4°C. 61 Loss of leaf area by defoliation can be analogous to excess shading within the vine canopy (18). Excess shading, caused by improper vine management, could result in hardiness situations in bark and buds similar to those already described for defoliation of Concord grape vines. A reduction in cold hardiness by leaf area loss triggered losses in vine productivity, vine fruitfulness (fruit production per node), and vine size (45). When vine pro- ductivity is reduced, the vine may become over-stressed by subsequently excessive vegetative growth, resulting in loss of hardiness (35, 37). Pruning Severity After defoliation, pruning severity was the domi- nant factor influencing bark and bud hardiness in the non- defoliated plants. Light (60 + 10) pruning decreased vine size while increasing the number of nodes retained on the vine. The increase in node number increased the fruiting stress on the vine (45). Bark and buds on such a plant may not have had proper hardiness (35), either because excessive fruit depleted plant reserves, or too much vegetation retarded growth cessation in the fall. Balance pruned (30 + 10) vines, however, had less fruiting stress than 60 + 10 pruned vines while maintaining greater vine fruitfulness (45). Also, since vine size ‘was greater for balance pruned vines than for lightly 62 pruned vines, a proper balance was maintained on the vine between fruit production and vegetative growth. This condition enhanced the potential for maximum hardiness. Cluster Thinning Observations from this study indicate that cluster thinning occasionally raised hardiness levels lowered by light (60 + 10) pruning particularly when the vines were defoliated. Since developing fruit clusters compete successfully for vine reserves (24, 25, 46, 48), their removal would make additional reserves available for more effective bark and bud maturation and thus for greater hardiness. Trellis Height Solid trends in bark and bud hardiness resulting from trellis height were absent. However, mid-winter (1971) and early spring (1972) bud hardiness was occasionally favored by the low trellis. This could be most reasonably explained as follows. A significant air temperature gradient was present from the top of the high trellis to the ground. Field measurements have indicated that air temperatures at the top of a conventional 2 m high trellis can be as much as 20°F warmer than at ground level on a still, cold night (data not shown). Buds consistently exposed to low temperatures would be more hardy than buds exposed to higher temperatures (43). 63 It is reasonable to suggest that viticultural stresses such as leaf area loss (defoliation; shading), light pruning, and a heavy fruit load on the vine acted together to influence vine cold hardiness. Since vineyard practices influence vine productivity (45), and since pro- ductivity and cold hardiness can be directly associated, vine hardiness must ultimately be affected. Good hardiness and productivity complimented each other and resulted in 'well-balanced vines (vegetative growth vs. fruit pro- duction) with optimal cropping conditions and fruit quality. :— U : cm 64 .Amoon How 9 mm oammmuoxov monoumuomeu Hm>fl>usm amasoa aum0flosfl mosao> .mhma .mm Hangs ou Heme .m Hanouoo Scum macfl> A.q womanema mHuH>v macho ouoosoo mo moon Numfiflum too sumo osfl>fla m0 homespun coaumfiflaoommo can sowuofiflaood .H .mHm “W ‘1' H musmflm v0.22. 92.5.: .o: cogff nocff .oc nocff .3: 6.5:... 3: .voEInOIOw 60:32. 0.1.00 60:33 o_+on .uoeaa o_+on 60:33 o_+ow 60:33 07.190 6.5.73 o_+on 6052a o_+0n €0.23..qu .vc_o__0eou.o .oo.o__o:u.u .oo.o:oeou.u 620:3... soc-o .vo.o__o.ov .o: .0 60.3.0.0... soc-m 633.30.. 3:. < v- R A M R P BARK LIVING mN ..__mn_< n. t__ma< 0N Iom<2 __ mums—Nome m mum2w>oz N mumOFoO xxxxxxxx coon Ix :20: .0: u 0. 2:0: 30. ID 2:2. so: . I Iouwoom< Immunomc. Ioumooma. Ioumoomd. Iommoom< Iomwoomd. (OoJEHOIVHBdWBI 'lVAIAHflS IS‘SMO'I I t I , t111.../—.,_—,..._1,_._,__.=12... E__.:=.__..:_::E1.1.1:.1..sillieellei ease-.52..1.1:...nitrate-1...5.5... _._._,_..._._.1....;\ cm .Amosn How a no ommmmumxmv 66 monsumuamamu HM>H>Hsm umwzoa aumoflosw madam> .mhma .mH Hands o» tha .m HoQODOO Eoum mosw> “.4 momsuema mfiuw>v datum ouoosou mo mode mumswnm new Muse osH>HH mo monoupmm goaumaflaoomao one coaumsaaoog .N .oam 67 -- N muomwh ‘I::.£. ‘O::_€. >0: Vice—fi— V.=:_£— so: VI::_£. V.:=_‘~ >0: 0.:c_£- U.S.—tn. .0: 62:... 07.3 .u.:=.ao_+ow .35.... o_+on 62:32:; 62...... o_+oo 62:... 0:06 62...... 0:0» 62...... olon v- R A M R D- BARK LIVING 6.2.9.3.: 6.323.... 5 6.2.1.9.... . a 6:33.; .u 6.2.23... 2...... 6:23.... .2. .0 £133.; .2. . m .3323; 3...... m_ .Zma< _N Iomdz m. mmmeomo _N mwm2m>oz m. mumOHoO 2:3. 33 . l 2...... .13.. . I Iwumoomd IOumoom< Ioumoomd. Iwumoom< 10mmoom< 1.0 O " 9' ID l [0 r N I (OoJBHOIVHBdWBJ. "IV/\IAHF’S ISBMO'I 68 :lTILIZI— ~.1I__I__I_1I:.I_.1I__..,I:I. T...II:,-:.-:.-:I:-TI\ :IZ-xaI:I:.:I:I:I\ T.........I:I.....-:......_I..._I...I\ .........I.._HI...._.......I..ITI\ .oma mm oommmumxo out monopmummsap Hm>w>usm unasoq .mnma .mm Hfluom ou Heme .N Honouoo Scum mocfl> A.q monounma mHuH>V ammuo ouoooou mo moon mumwuumu can humocooam mo msuouumm coaumfiflaoomoo was soflumEHHoom om emufih 69 m musmfim 622:: 623:. oIow 626:2... . I 62.5... .2. 625:. 9+8 6223.... . o toes—2 6:53 oron 6233.2. .... 62.5... .2. .0255 0. +0» .vo.u:o‘ou - w 62...... 02.3. 622.36 .9. . o 6.5:... 625:. otow 622.2... .2. . o 00:55 .0: 9.2.5.... 62.5... .0... 625:. 9.3 625398... 630:3... .oc.m 66., .eu .3: mm J_m&< D U B Y R A T R E , 1.. T H . H. ,. __x.x_.... a... 6666.x W :16: .oc.® B m___0..~ Ina—IE n:_o: co_;.ll v- R A D N O c E 4 c. xxx x.x m _ J_mn_< mm Iom<2 Iwumoomd. Ioumooma‘ Ioumoom< mmmimomo w mwm2w>oz N mmmOLvC. 1:: __ 1... ON: 2 I!) o "IVAIAM‘IS ISBMC.‘ ON- 9 Iouwoom< Iomwoom< Iomwoomd m ._r z m .2 ._. < w m .r ‘L IO (3.) BHOIVUBdINT-JJ 70 A mm", ....I:-:-:-1_-._._-1_-:-_ _..-:-:-:-:-:-:-.1= 11.51.:‘.1.._-....h..._..hs;..\h\\._i..._.§\,§\..i...,..~e...‘.....\...,i\‘5‘ .‘f‘. ‘_\ .\\ .omB no commowmxo mum mandamummfiou Ho>fi>H5m unasoq .mnaa .mH kumd on mhma .m Haeouoo Eoum masa> A.q nonsense mflufl>v macho ouoosoo mo moon mumwuuau one mucosooom mo msuauumm sowumfiwaoomoo tom coauofiwaood .6 .oflm nu “U Ru BUD TERTIARY w gunmen v0.2.5. .0: 9.5.2: .voesta 0_+On .vo=:.n 0.6.00 6..o._o:u.w .vo.u._o.ou.o:.o m. mums—woman. .N iii-n. It. VIE—:E. .0: “CCC—fl. ”DEC—£9 .0: 6:330:00 6.5.; Soon 62...; o:on .uo.o:o.ov.°:ou 60.020.00 .oeum 6.323.“. .o...< mmmZm>OZ m. mmmOhoO . I IO N I I (Do) BHOIVHBdWEJ. WVAIABDS lSBMO'I ID I SECONDARY I 0 m m 0 U m < I 0 u m D o m < I 0 m m o O m < I O u m D o m < I 0 u w o 0 m < 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. LITERATURE CITED Banta, E. S., G. A. Cahoon and R. G. Hill. 1970. Grape growing. Ohio State Univ. Coop. Ext. Ser. Bul. No. 509. 24 pp. Clark, J. H. 1936. Injury to buds of grape varieties caused by low temperatures. Proc. Amer. Soc. Hort Sci. 34: 408-413. Clore, W. J., M. A. Wallace, and R. D. Fay. 1974. Bud survival of grape varieties at sub-zero temperatures in Washington. Amer. J. Enol. Viticult. 25(1): 24-29. Dethier, B. E. and N. Shaulis. 1964. Minimizing the hazard of cold in New York vineyards. New York Agr. Expt. Sta. Bul. No. 1127. 7 pp. Edgerton, L. J. and N. J. Shaulis. 1953. The effect of time of pruning on cold hardiness of Concord grape canes. Proc. Amer. Soc. Hort. Sci. 63:209- 213. Folwell, R. J. 1973. The market situation and outlook for Concord grapes.l973. Washington State Grape Society Proc., 1973. 11 pp. Fuchigami, L. H., C. J. weiser, and D. R. Evert. 1971. Induction of cold acclimation in Cornus stolonifera Michx. Plant Physiol. 47:98-103. , and D. G. Richardson. 1973. THe influence of sugars on growth and cold accli- mation of excised stems of Red-osier dogwood. J. Amer. Soc. Hort. Sci. 98(5): 444-447. Haeseler, C. W. 1970. Climatic factors in the potential for wine grape production in several areas of Pennsylvania. Penn. State University Agr. Expt. Sta. Prog. Report. No. 303. Howell, G. S., and C. J. weiser. 1970. Fluctuations in the cold resistance of apple twigs during spring dehardening. J. Amer. Soc. Hort. Sci. (95)2: 190-192. 72 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 73 Howell, G. S., and C. J. weiser. 1970. The environ- mental control of cold acclimation in apple. Plant Physiol. 45: 390-394. and S. S. Stackhouse. 1973. The effect of defoIiation time on acclimation and dehardening in tart cherry (Prunus cerasus L.). J. Amer. Soc. Hort. Sci. 9812): I323I36. Hurst, C., T. C. Hall, and C. J. Wieser. 1967. Reception of the light stimulus for cold accli- mation in Cornus stolonifera Michx. HortScience 2(4): 164-I66. Irving, M. R. and F. O. Lanphear. 1967. The long day leaf as a source of cold hardiness inhibitors. Plant Physiol. 42: 1384-1388. Khudairi, A. K. and R. C. Hamals. 1954. The relative sensitivity of Xanthium leaves of different ages to photoperiodic induction. Plant Physiol. 29: 251-257. Kliewer, W. M., L. A. Lider, and N. Ferrari. 1972. Effects of controlled temperature and light intensity on growth and carbohydrate levels of Thompson Seedless grapevines. J. Amer. Soc. Hort. Sci. 97(2): 185-188. Larsen, R. P., H. K. Bell, and J. Mandigo. 1957. Pruning grapes in Michigan. Mich. State Univ. Exten. Bul. No. 347. 16 pp. May, P., N. J. Shaulis, and A. J. Antcliff. 1969. The effect of controlled defoliation in the Sul- tana vine. Amer. J. Enol. Viticult. 20(4): 237- 250. Michigan Dept. of Agriculture. Michigan Agricultural Statistics. June, 1974. p. 24. New York State Dept. of Agriculture and Markets, Bureau of Statistics; New York Crop Renting Service. New York Orchard and Vineyard Survey-- 1970. AMA Release No. 125. July, 1971. pp. 30-34. New York Dept. of Agriculture and Markets, Bureau of Statistics; New York Crop Reporting Service. Fruit Report. January 1, 1974. ‘ 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 74 Olien, C. R. 1967. Freezing stresses and survival. Ann. Rev. Plant Pysiol. 18:387-408. Partridge, N. L. 1925. Profitable pruning of the Concord grape. Mich. Agr. College Agr. Expt. Sta. Special Bul. No. 141. 12 pp. . 1925. The fruiting habits and pruning of Ehe Concord grape. Mich. State Agr. Expt. Sta. Tech. Bull. No. 69. 39 pp. . 1931. The influence of long pruning and 1nning upon the quality of Concord grapes. Proc. Amer. Soc. Hort. Sci. 28: 144-146. , and A. Sakai. 1969. Freezing resistance 1n grape vines. Hokkaido Univ., Low Temp. Sci. Ser. B 27: 125-144. Pogosyan, K. S., and M. M. Sarkisova. 1967. Frost resistance of grape varieties in relation to the condition of hardening. Soviet Plant Physiol. 14: 886-891. Potter, G. F. 1938. Low Temperature effects on woody plants. Proc. Amer. Soc. Hort. Sci. 36: 185-195. Proebsting, E. L. 1963. The role of air temperature and bud develoPment in determining hardiness of dormant 'Elberta' peach buds. Proc. Amer. Soc. Hort. Sci., 83: 259-269. , and H. H. Mills. 1961. Loss of hardiness 5y peach fruit buds as related to their morpho- logical development during the prebloom and bloom period. Proc. Amer. Soc. Hort. Sci. 78: 104-110. , and . 1972. A comparison of Hard1ness responses in fruit buds of 'Bing' cherry and 'Elberta' peach. J. Amer. Soc. Hort. Sci. 97(6): 802-806. Sakai, A. 1966. Temperature fluctuation in wintering trees. Physiol. Plantarum 19: 105-114. . 1966. Studies of frost hardiness in woody plants. II. Effect of temperature on hardening. Plant physiol. 41: 353-359. Shaulis, N. 1970. New York site selection for wine grapes. Proc. New York State Hort. Soc. 115: 288- 294. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 75 Shaulis, N. 1971. Vine hardiness a part of the problem of hardiness to cold in New York vineyards. Proc. New York State Hort. Soc. 116: 158-167. , H. Amberg, and D. Crowe. 1966. Response of Concord grapes to light, exposure and Geneva Double Curtain training Proc. Amer. Soc. Hort. Sci. 89: 268-280. , J. Einset, and A. B. Pack. 1968. Growing cold-tender grape varieties in New York. New York Agr. Expt. Sta. Bul. No. 821. Smart, R. E. 1973. Sunlight interception by vineyards. Amer. J. Enol. Viticul. 24(4): 141-147. Steponkus, P. L., and F. O. Lanphear. 1966. The role of light in cold acclimation. Proc. XVII Inter- national Hort, Congress. 1: 93. , and . 1967. Light stimulation of cold acclimation: Production of a translocatable promoter, Plant Physiol. 42(12): 1973-1679. , and . 1968. The relationship of carbohydrates to cold acclimation of Hedera helix L. cv. Thorndale. Physiol. Plant 21: 777-791. Stergios, B. G., and G. S. Howell. 1972. Evaluation of viability tests for cold stressed plants. J. Amer. Soc. Hort. Sci. 98(4): 325-330. , and . 1974. I£_Situ destruction of darmant 'Concord' grape primary Suds without secondary bud kill. HortScience 9: 120-122. , and . 1975. Effect of site on cold acclimation and deacclimation patterns in Concord grape (Vitis labrusca L.) Vines. Amer. J. Enol. Viticult. In preparation. , and . 1975. Effects of defoliation and cropping stress on the size and productivity of 'Concord' grape (Vitis labrusca L.) Vines. Amer. J. Enol. Viticult. In preparation. Tomkins, J., and N. Shaulis. 1957. The Catawba grape in New York. II. Some effects of severity of pruning on the production of fruit and wood. Proc. Amer. Soc. Hort. Sci. 66: 214-219. 76 47. Wildermuth, R., J. A. Kerr, F. W. Trull, and J. W. Stack. 1926. Soil survey of Van Buren Co., Michigan. U.S. Dept. of Agriculture, Bureau of Soils. 42 pp. 48. Winkler, A. J. 1970. General viticulture. Univ. Calif. Press. Berkeley, Los Angeles, London. 633 pp. SECTION FOUR EFFECTS OF DEFOLIATION AND CROPPING STRESS ON THE SIZE AND PRODUCTIVITY OF Vitis labrusca L. var. Concord Vines EFFECTS OF DEFOLIATION AND CROPPING STRESS ON THE SIZE AND PRODUCTIVITY OF Vitis labrusca l L. var. Concord Vines Basil G. Stergios2 and Gordon S. Howell Michigan State University, East Lansing Abstract Vine size and productivity of culturally stressed Concord (Vitis labrusca L.) grape vines were investigated in southwestern Michigan from 1971 to 1973. Defoliation, pruning severity, and cluster thinning individually and collectively influenced vine size, and productivity as measured by yield, fruitfulness, berry size, soluble solids, clusters per vine, clusters per node, total vine sugar, .and cluster size. Leaf removal caused a reduction in all factors of productivity, particularly total vine sugar (59%): yield (50%), fruitfulness (37%), clusters per node 1Received for publication . Michigan .Agricultural Experiment Station Journal Article No. . 2Present address: Fundacion Servicio para el .Agricultor (FUSAGRI), Calle 78, No. 46 - 21, Maracaibo, Venezuela. .Acknowledgments: we wish to express our appreciation to rmanbers of the National Grape Cooperative in Lawton, .Michigan, Dr. Nelson Shaulis of The Geneva ExPeriment Station, and Stephen Stackhouse of Michigan State Uni- versity for their help, guidance, and critical inputs. 77 78 (23%), soluble solids (22%), and vine size (22%). Light (60 + 10) pruning increased the number of nodes retained which decreased vine fruitfulness. Yields were initially higher from lightly pruned vines than from balance (30 + 10) pruned vines even though fruitfulness was low. Later, however, balance pruned vines yielded as much fruit than lightly pruned vines while still maintaining a higher level of fruitfulness and total vine sugar. Although cluster size and the number of nodes per vine increased on cluster thinned vine, fruitfulness, cluster number per node, and total vine sugar was reduced. Defoliation and cluster thinning interacted most frequently to lower vine produc- tivity. Introduction A vineyard will give highest returns only if it can produce maximum amounts of fruit of the desired quality over a long period of time (9). In order to achieve this goal, the various cultural stresses affecting vine growth and productivity must first be examined. Previous studies have demonstrated certain effects that cultural practices can.have on vine size, productivity (yield and fruit quality), and cold hardiness. The reduction of functional leaf area by defoliation, thus simulating vine shading, has resulted in reduced vine productivity (9). Pruning severity has been investigated in relation to vine size 79 (l, 2, 5, 16, 17, 21) and vine productivity (5, 7, 16, 17, 21). The relationship of cluster thinning to vine size (1, l7) and productivity (1, 3, 12, 13, 17) has also been investigated. Shaulis and Steel (17) investigated the effect of pruning severity, cluster thinning, rootstock, and weed control on vine size and certain productivity factors of Concord grape vines. However, information regarding the combined effects of leaf removal and cropping stress on vine size and productivity incomplete. Cold hardiness of Concord grape buds was reduced by defoliation and cropping stress (20). But cold hardiness and vine productivity were closely associated when they were influenced by cultural stress, and the response was synergistic (20). Cultural stresses induced by vineyard management techniques could influence the vine size and productivity of grape vines, either indirectly by reducing vine hardi- ness, or by the direct reduction of yield and fruitfulness. This study was initiated to investigate the individual and combined effects of hand defoliation, pruning severity, and cluster thinning on the size and productivity of Concord (Vitis labrusca L.) grape vines. Methods and Materials The Study Area Two 4.0 ha Concord grape vineyards located in Van Buren County, Michigan (T38, R13W, Sec. 32) were selected 80 for the study. The first vineyard is located on a high (elev. approx. 277 m above sea level) site. It is sur- rounded by other vineyards situated to the east and south, and open fields to the north. The second vineyard is located on a low (elev. approx. 256 m above sea level) site directly west of the first site. It occupies a depression surrounded on the south and west by other vine- yards and on the north by open fields. The two study sites are approximately 210 m apart, separated by a 6° slope containing a tart cherry (Prunus cerasus L.) orchard. The high site topography is fairly homogeneous while the low site tapers off gently into a pocket at the southwest corner. The grape vines on both sites were planted in 1904 on Plainfield sand (22), and have since undergone inter- mittant renewal. They were planted rows of 48 vines, spaced at 2.5 m, with 2.8 m between the rows. Experimental Design and SamplingiProcedures Fruit samples and vine size data were obtained from 288 vines which were selected for uniformity in each site in 1970. The vines were trained to umbrella kniffen and constituted a 2.5 ha experimental plot at each site. Each plot was designed independently as a randomized block experiment with 6 blocks. There were 8 treatments per block and 6 vines were used for each treatment. Each 81 treatment consisted of a combination of the three variables: defoliation, pruning severity, and cluster thinning and are ranked in order from the least to the most treatment stress as follows: Not defoliated, 30 + 10 pruned, thinned Not defoliated, 60 + 10 pruned, thinned Not defoliated, 30 + 10 pruned, not thinned Not defoliated, 60 + 10 pruned, not thinned Defoliated, 30 + 10 pruned, thinned Defoliated, 60 + 10 pruned, thinned Defoliated, 30 + 10 pruned, not thinned Defoliated, 60 + 10 pruned, not thinned The vines were either balance pruned at 30 + 10 or pruned less severely at 60 + 10 during the mid-winter of 1971, 1972, and 1973. A vine was balance pruned when 30 buds were left for the first pound of current cane growth removed (prunings), and 10 more buds were left for each additional pound of removed prunings (6, 10). Designated vines were cluster thinned by hand to one cluster per shoot at anthesis (around the second week in June for all three years). Designated vines were completely defoliated by hand at verasion (initiation of fruit coloring) which occurred during the third to fourth week of August in 1971, 1972, and 1973. 82 Main effects (the effect of any single variable on vine size and productivity) and treatment effects (the combined effects of two or more interacting variables) were evaluated by means of a factorial analysis of the variance by means of individual degrees of freedom (18). The means were compared using the Tukey statistic (18). Results generated from the high site experiment were analyzed independently from the low site results. Vine measurements for each experiment were made at harvest time (late September to early October) in 1971, 1972, and 1973 for the following factors involving vine productivity (1?): A. Yield of fruit in Kg per vine B. The percent soluble solids content of the fruit C. Berry size (g per berry) D. The number of clusters per vine E. The number of nodes per vine The vine size in each experiment was measured as the amount of cane prunings kg per vine (3, 5, 17, 21) obtained during the winter of 1971, 1972, and 1973. The number of nodes retained (5, 17) after the vines were either balance (30 + 10) pruned or more lightly (60 + 10) pruned was also recorded. Vine fruitfulness was expressed as the kg of fruit produced per node retained, and calcu- lated as follows. at nu» qfi‘ . ., a. “ ‘ 3;: ‘ ‘4‘“- 83 Yield (kg) Fru1tfulness = Number ofgnodes retained Total vine sugar (kg sugar per vine) was determined from the soluble solids of the fruit and vine yield as follows: kg sugar = [soluble sol1digb[y1eld (Kg)] The rumber of clusters per node were calculated as follows: No. clusters per vine No. clusters/node = No. nodes per vine Cluster size (9 per cluster) was calculated as follows: [Yield (Kg)] [1000] lust r size = - C e No. clusters per V1ne The number of berries per cluster were determined as follows: Cluster size (g) No. berr1es/cluster = Eerry size (9) Results The effects of defoliation, pruning severity, and tcluster thinning on vine size and productivity from both the high and the low experimental plots in 1971, 1972, ahd.l973 are shown in Tables 1 - 6. Only those results vflrich were statistically significant have been mentioned. 84 Vine Size and Nodes Retained Vine size was not influenced by defoliation and cropping stress in 1971. The number of nodes retained in 1971 was not affected by defoliation and fruiting stress, but was higher on the lightly (60 + 10) pruned vines (Table 1). While both leaf removal and cropping stress reduced the size of high site vines in 1972, only leaf removal reduced vine size in the low site (Table 2). Defoliation reduced the number of nodes retained in both sites in 1972, but the number of retained nodes on prune- stressed and cluster thinned vines was higher. Defoliation reduced vine size again in 1973. CrOpping stress affected vine size only in the low site where cluster thinned vines were larger (Table 3). Defoliation and light pruning reduced the number of retained nodes again in 1973, but fruiting stress had no effect. Low site vines were gen- erally bigger than high site vines in 1971 and 1972. But this was reversed in 1973. 12212 Fruit production was reduced by leaf removal in all three years (Tables 4, 5, and 6). However, light pruning increased fruit production in 1972. Treatment effects were evident in 1972. The 1972 high site yield 'was greater from lightly pruned vines than from balance pruned vines when the leaves were retained (Table 5). 85 Upon defoliation, the yield declined sharply for both balance pruned and lightly pruned vines, but the latter still produced a higher yield (Fig. 1). On the low site in 1972, the yield was greater from nonthinned vines than from thinned vines. The yield from nonthinned vines declined more when the leaves were removed than it did when the vines were thinned (Figs. 2 and 3). Although light pruning produced higher yields in 1973, the differences were not significant (Table 6). Both leaf removal and cluster thinning decreased yield as they did in 1972. Treatment effects in 1973 revealed that high and low site yields were influenced by defoliation and cluster thinning as they were in 1972, except that non- thinned vines retained higher yields even when defoliated (Figs. 4 and 5). we observed that low site yields were generally higher than high site yields in 1971 and 1972, but lower than high site yields in 1973. Fruitfulness and Clusters Per Node Leaf removal and light pruning reduced vine fruit- fulness (kg fruit per node) and cluster number per node in 1971 (Table 4) and 1972 (Table 5). Fruitfulness was greater when the vines were not cluster thinned (Tables 4 and 5; Fig. 6). When the leaves were removed, however, fruitfulness declined sharply for both thinned and 86 nonthinned vines, but still remained greater for the non- thinned vines. Results in 1973 were similar to those obtained in 1971 and 1972, except that pruning severity had no effect on the number of clusters per node. A treatment effect on fruitfulness involving defoliation and cluster thinning as occurred in 1972 also occurred in 1973 (Fig. 7). The number of clusters per node was greater in 1972 from nonthinned vines than from thinned vines when they were not defoliated. Upon defoliation, clusters per node declined more for nonthinned vines than for thinned vines, but still remained the greater of the two (Fig. 3). High site vine fruitfulness was generally lower than low site vine fruitfulness in 1971 and 1972, but high site vines generally had more fruit per node than low site vines in 1973. Vine fruitfulness generally increased from 1971 to 1972, but no additional increases were evident in 1973. Cluster Number and Size Defoliation had no effect on cluster number in 1971 (Table 4), but cluster size was reduced (low site only). Light pruning increased cluster number as expected, but decreased cluster size (Table 4). Cluster size was increased by balance pruning (low site only), while cluster number was decreased. In 1972, leaf removal caused a 87 reduction in cluster number, but had no effect on cluster size (Table 5). By 1973, however, leaf removal had reduced the cluster size (Table 5). The cluster number was simi- larly affected (as in 1972). Light pruning reduced cluster size in 1972, (high site vines only) while increasing cluster number (Table 5). Cluster number and size response from vines stressed by cropping in 1973 was similar to the response from the first year evaluated. Leaf-removal and cluster thinning interacted to influence the cluster number of low site vines in 1972, and of both high and low site vines in 1973. The number of clusters was much greater on nonthinned than on thinned vines for the nondefoliated plants in 1972. Cluster pro- duction, however, declined on both nonthinned and thinned vines when the leaves were removed. In addition, non- thinned vines showed a much greater cluster number decline than thinned vines (Fig. 8). Leaf removal and cluster thinning had a similar effect on cluster number in 1973 as they did in 1972, except that the cluster number on defoliated vines remained greater on nonthinned vines than on thinned vines (Figs. 9 and 10). On high site vines in 1972, leaf removal and pruning severity had a combined effect on cluster number. The cluster number from non- defoliated vines was greater than from defoliated vines when the vines were balance pruned (Fig. 11). However, when the vines were lightly pruned, the number of 88 clusters on nondefoliated vines greatly increased, while those on defoliated vines increased only slightly. Leaf removal and cluster thinning also interacted to determine cluster size of high site vines in 1973. Cluster size on nondefoliated vines was greater when they were thinned (Fig. 12). When the vines were defoliated, cluster size decreased more on nonthinned vines than on thinned vines. Vine Sugar Leaf removal decreased the sugar-yield/vine of vines from both sites in all three years evaluated (Tables 4, 5, and 6). Light pruning increased the sugar from vines from both sites in 1971, but only from high site vines in 1972 (Tables 4 and 5). In 1973, vine sugar was not significantly increased by light pruning (Table 6). Vine sugar increased in all three years evaluated when fruiting stress was heavy (Tables 4, 5, and 6). Leaf removal and cluster thinning decreased the vine sugar of high site vines in 1971, and of all vines in 1973. In 1971 and 1973, sugar was much greater from nonthinned vines than from thinned vines when the vines were not defoliated (Figs. 13, 14, and 15). However, when the leaves were removed, the vine sugar decreased more for nonthinned vines than it did for thinned vines. ‘ C .'l ..u .0. 9.5 ‘4’ Wu .‘jt'.’ s sf." he a,“ A '5: 1.. .1.. (D ’f L); I I (I! 89 Pruning severity combined with leaf removal to affect high site vine sugar in 1972. Lightly pruned vines had more total sugar than balance pruned vines when they had leaves. When the vines were defoliated, however, the vine sugar of both 30 + 10 and 60 + 10 pruned vines was greatly reduced (Fig. 16). Berry Size and Number of Berries Per Cluster Both defoliation and fruiting stress reduced the berry size of low and high site vines in 1971 (Table 4). Berry size was also reduced by light pruning in 1971, but only on the low site vines. Leaf removal significantly increased berry number per cluster in 1971 (Table l). but decreased it in 1973 (Table 3). Both balance pruning and cluster thinning increased the number of berries per cluster in 1971 and again in 1973. There was no effect in 1972 (Table 2). Defoliation reduced berry size at both sites in 1972, but pruning severity combined with leaf removal to decrease the berry size of high site vines. Berry size ‘was greater when balance pruned vines were not defoliated. 1However, when the vines were lightly pruned, berries from the nondefoliated vines showed a sharp size decrease (Fig. 17). Leaf removal and cluster thinning combined to reduce berry size in 1973 (Table 6). Berries from high 90 site, nondefoliated vines were about the same size for thinned vines as for nonthinned vines (Fig. 18). But when the vines were defoliated, berry size was reduced much less when they were thinned than when they were not thinned. Pruning severity effects also combined with the effects of fruiting stress to reduce berry size. Berry size was greater in 1973 when high site, balance pruned vines were thinned (Fig. 19). However, when the vines were lightly pruned, berries from the thinned vines showed only a slight size increase. At the same time, berries from the lightly pruned, nonthinned vines decreased in size. Cluster thinning and leaf removal effects inter- acted to determine the number of berries per cluster in 1973 (Fig. 20). When the vines were not defoliated the number of berries per cluster was higher for thinned vines than for nonthinned vines. When the vines were defoliated, the number of berries per cluster for thinned vines declined only slightly, while the berry number per cluster for the nonthinned vines declined greatly. Soluble Solids Only leaf removal markedly reduced the percent of sugar in the fruit of high site vines in 1971 (Table 4). Leaf removal reduced fruit solids again in 1972 and in 1973 (Tables 5 and 6). Pruning and fruiting stress also 91 caused a reduction of fruit solids in 1972, as demon- strated by the lightly pruned, high site vines and the nonthinned, low site vines (Table 5). The reduction of fruit solids from defoliated, high site vines in 1973 was also determined by pruning effects. The fruit solids of high site, nondefoliated vines was nearly the same for both balance pruned and lightly pruned vines. However, when the vines were defoliated, the fruit solids of lightly pruned vines decreased more than the fruit solids of balance pruned vines (Fig. 21). Discussion Leaf removal, pruning severity, and cluster thin- ning individually and collectively affected Concord grape- vine size and productivity during the years evaluated. Some productivity differences which were not apparent during the first year appeared in 1972 and 1973. In high site vines, for example, defoliation had no effect on vine fruitfulness in 1971, but the fruitfulness of nondefoliated vines was significantly higher than the fruitfulness of defoliated vines in 1972, and again in 1973. High and low site differences in productivity were not specifically compared. One possible explanation for the generally greater productivity in the low site in 1971 and 1972 may be less bud injury due to greater cold 92 hardiness (19). When severe freezes occur, however, the low site vines become susceptible to low temperature injury when air drainage is poor. Occurrences of such freezes in the late spring of 1973 were partially responsible for the general decline in low site vine productivity evident in 1973. Defoliation Leaf removal caused a reduction in all factors of productivity from 1971 to 1973 regardless of site. The average reduction in yield due to complete defoliation in 1972 and in 1973 was 50%. Other significant reductions in productivity due to defoliation were 37% for fruitful- ness (yield/node), and 23% for clusters per node. In 1971, we found that the number of berries per cluster was significantly greater for defoliated vines than for non- defoliated vines. This was contrary to the findings of May gt 21, (9), who found that the number of berries per cluster decreased sharply upon defoliation. However, they ‘were working with "Sultana" vines rather than "Concord.“ Interspecific differences (2. Vinifera vs. 2. labrusca) as well as differences in experimental procedures can account for the differing results. They (9) defoliated 4 to 6 weeks after anthesis at about the time the berries enter the lag phase of growth (4). They also reported the severity of productivity decline increased with i 93 increased levels of defoliation (by removal of the non- fruiting shoots and defoliation of fruiting shoots). Later (1973), however, our results showed that a trend toward lower berry number for clusters of defoliated vines was significantly evident. Next to yield, the most striking reduction in pro- ductivity due to defoliation was for total vine sugar (59%) which is the product of soluble solids and yield. May SE 31. (9) reported that on "Sultana“ vines, vine fruitfulness (yield/node) and clusters per node were the best measurements of the defoliation effect, but primarily because they had found a significant drop in the number of berries per cluster. . While our results showed a significant reduction in soluble solids (22%) with loss of leaf area, such was not generally the case in the "Sultana" vine (8, 9, 15). Our results demonstrated that defoliation signifi- cantly reduced "Concord" vine size by about 35%, while May gt_gl. (9) reported a statistically nonsignificant vine size reduction of 23% when "Sultana" vines were defoliated. Shaulis and May (15) also reported an increase in vine size with a restricted canopy (increased shading) for "Sultana" vines, and argued that increased growth occurred in shaded canopies due to decreased fruitfulness. They had pre- viously demonstrated (17) with "Concord" vines that a reduction of fruitfulness induced increased vine growth. 94 Shaulis gt_31. (14) had previously found, however, that the vine size of umbrella-trained “Concord" vines (10 nodes/cane) with their own roots was 10% less than the size of vines trained on the more exposed Double Curtain system with the same number of nodes per cane. Moreover, May's reported vine sizes occurred while obtaining an 81% decrease in fruitfulness due to defoliation (9). Since the physiological consequences of leaf removal are ultimately associated with the reduction of leaf area exposed to light, internal vine shading could also cause a reduction of vine productivity in the same manner as defoliation (9). An earlier study by May and Antcliff (8) indicated the productivity of “Sultana" vines in Australia was reduced by shading if it occurred between mid-November and December. Development of the Double Curtain system at Geneva, New York for training "Concord" vines (14) increased yields by increasing the exposed leaf area. More recently, Shaulis and May (15) found that the productivity of "Sultana“ vines was reduced by shading induced by a crowded (6 ft.) canopy. Pruning Severity Our data showed that light (60 + 10) pruning increased the number of nodes retained on the vine thereby decreasing fruitfulness, and in 1971 and in 1972, increas- ing yield and vine sugar. Initially, increased node 95 number directly caused higher yields even when fruitfulness was low. By 1973, it became evident that lightly pruned vines with a high node number and low fruitfulness had declined in yield and vine sugar to the point where they were no longer different from balance pruned vines, where yield was still increasing. Thus, balance pruned vines can yield as much fruit and total vine sugar as lightly pruned vines, while still maintaining a higher level of fruitfulness. Balance pruned vines can maintain greater vine size (pruning weight). Kimball and Shaulis (5) observed that declining exposure of leaf surface as vine size increases is a valid basis for the practice of balance pruning. It has been shown that improperly pruned vines were less productive because the amount of vegetative growth relative to fruit production was unbalanced (11, 16, 21). i The greater cluster size and greater number of clusters per node for balance pruned vines (as opposed to lightly pruned vines) observed in 1972 and in 1973 is in agreement with results obtained by Tompkins and Shaulis (21), and Shaulis and Steel (17). Cluster Thinning Early workers (3, ll, 12, 13, 17) have demon- strated that cluster thinning reduces the yield of grape vines. Partridge (11) and Ragland (12) argued that this 96 disadvantage would have been overcome for "Concord" vines by the large increase in cluster size, e3pecially if the vines were "long pruned" (11). This seems unreasonable in the light of our results. They show that although the cluster size and number of nodes per vine increased with cluster thinning, the fruitfulness and number of clusters per node of nonthinned vines was greater for all years evaluated. It is unlikely that a lighter pruning severity (long pruning) would improve the situation, as our data indicate that fruitfulness and number of clusters per node are lower for lightly pruned vines than for balance pruned vines. The results further indicate the infeasibility of cluster thinning "Concord" grape vines, as total vine sugar was consistently lower for thinned vines than for non- thinned vines.* Treatment Effects Defoliation and cluster thinning interacted most frequently to influence productivity. Greater rates of productivity decline were enhanced by a combination of more than one severe stress such as nonthinning or light pruning and leaf removal. 97 Table 1. Productivity and vine size of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1971. Values are main effect means on a per vine basis. Vine No. No. No. Site Variable Size Nodes Clusters Berries (Kg) Retained /node /cluster Not Defoliated 1.41 62.6 1.92 30.3 Defoliated 1.39 62.7 1.30 34.1* m 30 + 10 Pruned 1.38 50.0 1.99* 32.5 E 60 + 10 Pruned 1.42 73.3* 1.23 31.8 Not Thinned 1.36 61.4 1.76* 30.6 Thinned 1.44 63.8 0.96 33.8* Not Defoliated 1.49 66.79 1.46 31.3* Defoliatefi 1.53 67.90 1.42 28.6 E 30 + 10 Pruned 1.61* 55.34 1.47 31.4* A 60 + 10 Pruned 1.40 79.35* 1.41 28.4 Not Thinned 1.49 66.93 1.96* 27.6 Thinned 1.53 67.77 0.92 32.3* * = main effect difference @ 5% level of sig- nificance. 98 Table 2. Productivity and vine size of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1972. Values are main effect means on a per vine basis. Vine No. No. No. Site Variable Size Nodes Clusters Berries (Kg) Retained /node /cluster * * * Not Defoliated 1.39 65.2 1.43 37.3 Defoliated 1.13 58.3 0.98 38.5 k * 30 + 10 Pruned 1.34 48.8 1.26 40.6 m * 3 60 + 10 Pruned 1.18 74.7 1.15 35.2 51 * Not Thinned 1.14 59.7 1.46 36.0 * at Thinned 1.38 63.8 0.96 39.8 . * * # Not Defol1ated 1.23 60.3 1.82 38.0 Defoliated 0.99 55.6 0.92 43.0 3 30 + 10 Pruned 1.15 45.7 1.55* 40.3 o A 60 + 10 Pruned 1.06 70.3* 1.19 40.7 Not Thinned 1.03 55.8 1.62# 39.5 Thinned 1.18 60.1* 1.13 41.5 * = main effect differences @ 5% level of sig- nificance. # = main effect differences @ 5% level of sig- nificance and defoliation x cluster thinning (Fig. 3). 99 Table 3. Productivity and vine size of Concord grape vines from a high (elev. 277 m) and a low (elev. 256 m) site in southwestern Michigan in 1973. Values are main effect means on a per vine basis. Vine No. No. No. Site Variable Size Nodes Clusters Berries (Kg) Retained /node /Cluster Not Defoliated 1.64* 65.6* 1.53* 37.2# Defoliated 0.83 ' 48.2 1.31 33.6 30 + 10 Pruned 1.34 47.3 1.46 38.4* § 60 + 10 Pruned 1.13 66.5* 1.38 32.5 tn Not Thinned 1.18 54.3 1.84* 31.8 Thinned 1.29 59.4 1.00 39.0# Not Defoliated 1.39* 61.6* 1.13* 45.1 Defoliated 0.65 45.1 0.77 47.9 :3 30 + 10 Pruned 1.11 42.9 0.98 50.7* S 60 + 10 Pruned 0.93 63.8* 0.92 42.3 Not Thinned 0.90 51.2 1.14* 43.9 Thinned 1.14* 55.5 0.76 49.1* * = main effect difference @ 5% level of sig- nificance. # = main effect difference @ 5% level of sig- nificance and defoliation x cluster thinning interaction (Fig. 20). ..MH .mam. conuomnmuea meanness 100 Hmumsao x cOHuMHHomao one TOGMOHMHcon mo Hm>ma mm a mosoHTMMHo uoammo case n * .mocmoflmwcmam mo Ho>mH mm @ aocmHTMMfio uoomma same u « m.~m «oa.m 4m.aa am.o 46.ma mo.o ma.m smashes «m.mmH mm.~ m.om 4mm.H m.6a .ma.o .mm.oa sausage uoz «a.HHH mm.~ 6.6m 4wm.n H.ms Ha.o «so.m census on + co m 6.om 4mo.m 4H.mm ma.a m.ma 46H.o mm.a vacuum as + om M e.mm 6m.~ H.6m oo.a m.ma HH.o mm.a emumaaommo 6.6m 4mo.m 46.66 4mm.a 4H.aa 46H.o 4mm.m emumaaomoa uoz H.am .mn.m .m.moa mm.o «.mH oa.o ao.m accuses 4o.mon mo.m m.~m .m6.H o.mH 4ma.o «mm.m accuses uoz H 4m.om so.m m.aa «Hm.a H.mH ma.o 46m.m oceans on + as m H 6.65 ao.m m.ooa ao.a m.mH 46H.o mo.e amazes as + on m.wa mm.~ N.NOH mo.a m.ma mH.o ma.s emumaaommo 6.6m 45H.m 6.6m evm.a 4a.pa mH.o mm.a emumaaommo uoz mnmumsao “MN MW. 16s. meaaom .meoe\ms. .ms. 0 Hum 004m .02 .m am ummsm mansaom pangs same» age. > . human Haumsao .wflmmn asfl> you n so memos powwma same one masam> .Hhma cw snowsowz snoumaseDDOm ca open as emu .>aaav 30H m one As new .>0Hav now: u scum macH> momum onoocoo mo mafia acfl> one mufi>fluoscoum .6 means .Aha can .ma .m .H mmfimv coauomumucw muwua>mm ocflcsum x sowumeHommo can cosmowmwcowm mo Ha>aa mm @ moogmuaMMHo uoaumo case n @ .Am can .0 .N .mmwmv ocficcwnp Hmumcao x soaucHHOMTU can TUGmOAMfisoam mo Hm>ma mm @ monumuommao uoommm came n * .oOGMOAMHcoflm mo Ha>aa mm @ moosoummmao vacuum sacs u c 101 «.mv mm.m m.m~u vu.u 4H.6u cu.m cm.a vaccucu .~.oa mo.m m.muu 4mm.u m.mu chu.o *mo.ou vaccuca uoz 46.6m Ho.m m.muu mm.u , m.mu au.o avm.m vacuum cu + cm W s.oa mo.m u.o~u ~m.u c.6u asu.o aa.m vacuum OH + om u.ma ma.~ c.muu oa.o v.~u uu.o ov.m vauauuouac am.vou .m~.m m.muu tum.u .m.mu mo~.o moa.~u vauauuouac uoz m.ov mo.m a.u~u mo.u 6.6u ~u.o om.. vaccuce 4c.mm uo.m «.mou 4mm.u ~.vu .vu.o u~.m vaccucu uoz u. av.mm oo.m a.mou cum.u ~.au ~u.o cm.a vacuum cu + as m o.uv auu.m au.m~u ~u.u .m.au 4vu.o um.» vacuum cu + cm H u.mm ma.~ m.ouu mc.o v.~u uu.o us.m vauauuouac am.ua av~.m u.o~u aue.u 4a.vu «au.o aqc.ou vauauuouac uoz auauauuo wmwm wmwm .mm. avuuom .avoc\ms. .ms. aunauua> auum .oz muuam uauamao uamum aanuaom uuuum vaaus . . mum masam> .mflmme mow> Ham a so memos vacuum cams .mhma cw cmownowz sumumoznusom ca muHm “E wmm .>maov 30H c was AS hum .>mHmv some n Scum mmcfl> manna ouoocoo mo mNHm wcw> can muw>fluosconm . m 3an .AHN .oamv coauoeuousw muwuo>am osflcoum x coupeflaommo one moseOHMflcoflm mo Hm>ma mm @ mocauommwo powwow owes u o .1mu vca .mu .mu .6H .NH .uu .ou .c .m .6 .amum. couuoauaucu acuccucu HaumsHo x soapewHOMao one ooceo«MHcmHm mo Ho>aH mm @ monoummmao vacuum :HeE u e 102 .ooceOAMflcon mo Ho>oa mm o oucoHoMMfio powwow sees n c a.mm .mm.~ .m.mmu ma.o c.6u ou.o mu.m vaccuce .m.am ac.~ m.o~u emo.u c.6u .6u.o ema.v vaccuca uoz 4~.vm mm.~ m.muu mm.o 6.6u ou.o m~.v vacuum as + on m v.oa sa.~ 4v.oau ca.o v.6u 46H.o mv.m vacuum on + on «.mm me.~ c.mma mm.o m.~u ou.o au.6 vauauuouac 46.60 ec.~ u.m~u .mm.u «a.eu «cu.o .ma.a vauauuouac uoz m.am euo.m au.auu oo.u m.vu mu.o av.e vaccuce .m.mm cm.~ o.~m *mm.u n.6u *uu.o sum.m vaccucu uoz. H 4m.mm Nm.~ m.mm 6~.u «.6u mu.o um.m vacuum as + co m v.mv mm.~ 4v.muu mu.u v.6u .vu.o av.» vacuum om + on H o.ov Na.~ c.mm mv.o «.mu Nu.o am.m vauauuouac *m.um *mo.m *6.muu amc.u am.vu ecu.o caa.ou vauauuomac uoz auauauao wmwm wmwm .mm. avuuom .avoc\ax. .ms. auneuua> auum .oz muuam uauamao uemum aanuuom uuuum vuaus . . one mosae> .mwmen acfi> umm e co eaves vacuum gees . .mhma ca cemwnoflz cuaumosnusom cw open as emu .>0Hmv 30a e one as new >0Ha. noes e Scum mmcw> omeuo ouoosoo no mean acw> one huw>fluosooum . m manna Fig. Fig. Fig. Fig. Fig. Fig. 103 The effect of defoliation and pruning severity on the yield (Kg) from high site Cbncord grape vines in 1972. The effect of defoliation and cluster thinning on the yield (Kg) from low site Concord grape vines in 1972. The effect of defoliation and cluster thinning on the No. clusters per node frOm low site Concord grape vines in 1972. The effect of defoliation and cluster thinning on the yield (Kg) from high site Concord grape vines in 1973. The effect of defoliation and cluster thinning on the yield (Kg) from low site Concord grape vines in 1973. The effect of defoliation and cluster thinning on the fruitfulness (Kg per node) of low site Concord grape vines in 1972. ’0: 2mm 1g 01‘. 1.885 Figure 1 Figure 3 Figure 5 104 Figure 2 Figure 4 Figure 6 Fig. Fig. Fig. Fig. Fig. Fig. 10. 11. 12. The effect of defoliation and cluster thinning on 105 the fruitfulness (Kg/node) of high site Concord grape vines in 1973. The effect of defoliation and cluster thinning on the No. of clusters per vine from high site Concord grape vines in 1972. The effect of defoliation and cluster thinning on the No. of clusters per vine from low site Concord grape vines in 1972. The effect of on the No. of Concord grape The effect of on the No. of Concord grape The effect of defoliation and cluster thinning clusters per vine from low site vines in 1973. defoliation and pruning severity. clusters per vine from high site vines in 1973. defoliation and cluster thinning on the cluster size (g/cluster) from high site Concord grape vines in 1973. Nut Fig ".I “J {-4 106 F1 ure 8 Figure 7 g Figure 9 Figure 10 Figure 11 Figure 12 Fig. Fig. Fig.1 Fig. Fig. Fig. 17. 107 The effect of defoliation and cluster thinning on the total vine sugar (Kg) of high site Concord grape vines in 1971. The effect of defoliation and cluster thinning on the total vine sugar (Kg) of high site Concord grape vines in 1973. The effect of defoliation and cluster thinning on the total vine sugar (Kg) of low site Concord grape vines in 1973. The effect of defoliation and pruning severity on the total vine sugar (Kg) of high site Concord grape vines in 1972. The effect of defoliation and pruning severity on the berry size (9) from high site Concord grape vines in 1972. The effect of defoliation and cluster thinning on the berry size (9) from high site Concord grape vines in 1973. 108 Figure 14 Figure 13 Figure 15 . F1gure 16 Figure 17 Figure 18 Fig. 19. Fig. 20. Fig. 21. 109 The effect of pruning severity and cluster thinning on the berry size (g) from low site Concord grape vines in 1973. The effect of defoliation and cluster thinning on the No. of berries per cluster from high site Concord grape vines in 1973. The effect of defoliation and pruning severity on the soluble solids of the fruit of high site Concord grape vines in 1973. 110 Figure 19 Figure 20 Figure 21 10. LITERATURE CITED Bradt, O. A. 1967. Effect of pruning severity and bunch thinning on yield and vigor of Buffalo and Catawba grapes. Report of the Horticultural Research Institute of Ontario. pp. 22-27. Clore, w. J. and V. P. Brummund. 1969. The effect of fine size on the production of Concord grapes balance pruned. Proc. Amer. Soc. Hort. Sci. 78: 239-244. Hamilton, J. 1953. The effect of cluster thinning on maturity and yield of grapes on the Yuma Mesa. Proc. Amer. Soc. Hort. Sci. 62: 231-234. Harris, J. M., P. E. Kriedemann, and J. V. Possingham. 1968. Anatomical aspects of grape berry develop- ment. Vitis 7: 106-119. . Kimball, K. and N. Shaulis. 1958. Pruning effects on the growth, yield, and maturity of Concord grapes. Proc. Amer. Soc. Hort. Sci. 71: 167-176. Larsen, R. P. and H. K. Bell, and J. Mandigo. 1972. Pruning grapes in Michigan. Mich. State Univ. Ext. Bul. No. 347. 16 pp. Maney, T. J. and H. H. Plagge. 1935. A study of production and physiology of Concord grape vines as affected by variations in the severity of pruning. Proc. Amer. Soc. Hort. Sci. 32: 392-396. May, P. and A. J. Antcliff. 1963. The effect of shading on fruitfulness and yield in the sultana. ,eN. J. Shaulis, and A. J. Antcliff. 1969. —The effect of controlled defoliation in the Sultana vine. Amer. J. Enol. Viticul. 20(4): 237-250. Partridge, N. L. 1925. The fruiting habits and pruning of the Concord grape. Mich. State College Agri. Expt. Sta. Tech. Bul. No. 69. 39 pp. 111 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 112 Partridge, N. L. 1931. The influence of long pruning and thinning upon the quality of Concord grapes. Proc. Amer. Soc. Hort. Sci. 28: 144-146. Ragland, C. H. 1940. A preliminary report on the effect of cluster thinning on the maturity, yield, and cluster size of grapes. Proc. Amer. Soc. Hort. Sci. 37: 661-662. Sharples, G. C., R. H. Hilgeman, and R. L. Milne. 1957. The relation of cluster thinning and trunk girdling of Cardinal grapes to yield and quality of fruit in Arizona. Proc. Amer. Soc. Hort. Sci. 66: 225- 233. Shaulis, N., H. Amberg, and D. Crowe. 1966. Response of Concord grapes to light, exposure and Geneva double curtain training. Proc. Amer. Soc. Hort. Sci. 89: 268-280. and P. May. 1971. Response of 'Sultana' vines to training on a divided canopy and to shoot crowding. Amer. J. Enol. Viticult. 22(4): 215-222. and G. D. Oberle. 1948. Some effects of prun1ng severity and training on Fredonia and Concord grapes. Proc. Amer. Soc. Hort. Sci. 51: 263-270. and G. D. Steel. 1969. The interaction of res1stant rootstock to the nitrogen, weed control, pruning and thinning effects on the productivity of Concord grapevines. J. Amer. Soc. Hort. Sci. 94: 422-429. Steel, G. D. and J. H. Torrie. 1960. Principles and procedures in statistics. McGraw—Hill, New York. 481 pp. Stergios, B. G. and G. S. Howell. 1975. Effect of site on cold acclimation and deacclimation patterns in 'Concord' (Vitis labrusca L.) grape vines. Amer. J. Enol. Viticult. In preparation. and . 1975. Effects of defoliation, treIIis height, and cropping stress on the cold hardiness of 'Concord' (Vitis labrusca L.) grape vines. Amer. J. Enol. Viticult. In preparation. 113 21. Tomkins, J. and N. Shaulis. 1957. The Catawba grape in New York II Some effects of severity of pruning on the production of fruit and wood. Proc. Amer. Soc. Hort. Sci. 66: 214-219. 22. Wildermuth, R., J. A. Kerr, F. W. Trull, and J. W. Stack.. 1926. Soil Survey of Van Buren Co., Michigan. U.S. Dept. of Agriculture, Bureau of soils. SECTION FIVE £3 Situ DESTRUCTION OF DORMANT CONCORD GRAPE PRIMARY BUDS WITHOUT SECONDARY BUD KILL Reprinted from HORTSCIENCE, Vol. 9(2), April 1974 A publication of the American Society for Horticultural Science, Mt. Vernon, Virginia In Situ Destruction of Dormant ‘Concord’ Grape Primary Buds Without Secondary Bud Kill1 Basil G. Stergios and Gordon S. Howell Michigan State University, East Lansing Abstract. Field death of dormant primary ads of Vitis labrusca I. cv. Concord may be Iectively simuhted by in situ puncture with 1 aluminum needle super-cooled by liquid 2. This allows the subsequent development t‘the secondary budsforstudiesoftheir owth and productivity. A ‘Concord’ grape node contains a impound bud, comprised of individual 'imary, secondary, and tertiary buds "ig. l). The primary bud is more 'oductive and less hardy than the leceived for publication November 6, 1973. ichigan Agricultural Experiment Station turns] Article No. 6612. 20 secondary bud during periods of acclimation and deacclimation (l, 2, 4) and is thus more susceptible to low temperature injury in the field (1, 6).2 When the primary bud is killed, the secondary bud will grow, producing a shoot which will be 50-70% as proguctive as a typical primary shoot (6). This hardiness-production 2Howen, G. S., Stergios, B. G., and s. s. Stackhouse. 1972. Grape research: progress rpt. 1971. Hart. Rpt. 20. Michigan State University, East Lansing. 3Also confirmed by the authors, unpublished. 114 differential between primary and secondary buds is important for economic reasons to producers (6), but it also indicates an endogenous mechanism for control of bud hardiness which can differentiate as much as 10°C between the primary and secondary.2 The greater susceptibility of primary buds to field kill coupled with their much greater productivity leads to investigations to answer the following questions: Why is the primary bud less hardy? How does the primary bud influence hardiness and production of the secondary? These long term studies are presently underway. To proceed with these studies, it was necessary to develop a technique to simulate freezing destruction of the primary bud in situ without injury to the secondary bud. Such a technique would desirably be inexpensive, easily carried in the field, and selectively cause death by low temperature stress. This report describes such a device. HORTSCIENCE, V01. 9(2), APRIL 1974 115 SHARPENED TIP OF ALUMINUM ROD FOIL -COVERED CORK INSULATION Fig. l. A. Diagram of the leaf axil of ‘Concord’ grape showing relative positions of leaf scar, lateral shoot and 3 dormant buds B. Longisection in the plane of the axis through a node of ‘Concord’ grape showing 3 dormant buds. LAT = lateral shoot, LS = VENT ALUMINUN R00 PYREX FLASK uouro N2 leaf scar, 1 = primary bud, 2 = secondary Fig. 2. Portable apparatus for in situ destruction of ‘Concord' grape primary buds. consisting of bud, 3 = tertiary bud [from Pratt, 1959]. an aluminum rod with a sharpened tip super—cooled with liquid N2. The equipment needed was a 1000 excised canes containing these nodes ml Buchner flask, an aluminum rod, and brought them into the laboratory to liquid N2, and insulating material. The test for bud viability with the browning tip of the aluminum rod was machined test (Table I) and the growth test to a point, and the apparatus assembled (Table 2) according to the procedures of as in Fig. 2. The flask was slowly filled Stergios and Howell (5). A primary bud with liquid N2 allowing the rod to cool, was judged alive when it was all green, also cooling the sharp point (below injured when its center portion -73°C). We then carried the apparatus browned, and dead when entirely into the experimental vineyard on brown. The field mortality (control) March 15, 1973 and punctured a series was 10% for the primary buds and 0% of nodes in situ at the site of the for the secondary buds(n = ID). lnthe primary bud for l, 3, 5, 10, and 15 sec control material, primary buds grew timed by a wristwatch sweep hand. We normally, i.e., expanding in an oblique Table 1. Primary and secondary ‘Concord' grape bud viability by the “browning test" In response to puncture by an aluminum. liquid Nz-cooled needle for 5 time periods (n =l0 observations). Treatment time % uninjured % injured % dead (sec) Primary Secondary Primary Secondary Primary Secondary Control 90 100 0 0 10 0 Fractional 20 80 60 0 20 20 3 0 90 20 lo 80 0 5 0 50 0 30 100 20 10 0 20 0 20 100 60 IS 0 0 0 0 100 100 Table 2. Primary and secondary ‘Concord' grape bud viability by the “growth test" in response needle for 5 time periods (n = 10 observations). angle away from the leaf scar and oriented in the center of the node. while secondary bud growth was suppressed. Although secondary bud growth in the control was suppressed, all the buds were still alive based on the visual observation of cut controls (Table 2). When we quickly punctured the primary buds with the liquid Nz-cooled needle apparatus, 60-90% injury in the primary buds occurred. However, the percentage of these completely killed was small (Table l and 2). When the primary bud was subjected to the treatment for3 sec, 80 to 90% death was achieved coupled with 80% survival and growth of the secondary bud. Secondary infection in the node following primary bud puncture was not observed, and secondary bud mortality attributable to it was not apparent. At the present hardiness level and developmental stage of the buds, a 3—sec exposure to the liquid Nz-cooled needle produced the best results. Treatment at earlier or later dates in the fall or spring would require re-establishment of an appropriate exposure time. Puncture and needle , to puncture by an aluminum. liquid Nzeooled Treatment % uninjured but % injured time % growing no growth (no growth) % dead (sec) Primary Secondary Primary Secondary Primary Secondary Primary Secondar)‘ Control 80 0 10 IOO 0 0 10 0 Fractional 0 50 0 30 90 lo 10 10 3 0 80 0 0 10 IO 90 IO 5 0 30 0 30 0 20 100 20 IO 0 0 0 IO 0 l0 IOO 30 IS 0 0 0 0 0 0 100 IOO HORTSCIENCE. VOL. 9(2). APRIL 1974 III _A;JIU ——PYPEI’ —-LI9U‘CE in as -' . \. /r’ exposure for 5 sec caused higher injury in secondary buds than did 3 sec, and their growth was poor (Table l and 2). Treatment for 10 sec produced almost complete death for both primary and secondary buds (Table l and 2), and after 2 weeks, no growth occurred. When primary buds were punctured at ambient temperatures, we noted that tissue injury occurred only in the immediate area of the needle thrust, and in most cases was almost indistinguishable from healthy tissue. We feel that the liquid Nz—cooled aluminum needle apparatus will be a 122 116 satisfactory tool for in situ destruction of primary buds while still in the dormant stage, and at the same time, allowing growth of the secondary bud to proceed unimpaired for subsequent study in the field. Thus the technique can be used to answer fundamental questions of hardiness and productivity of secondary buds by varying the time that the primary is frozen in the field. literature Cited 1. Clark, J. H. 1936. injury to the buds of grape varieties caused by low temperatures. Proc. Amer. Soc. Hort. Sci. 342408413. . Pogosyan, . Sakai, A. . Wiggans, R. S., and M. M. Sarkisova. 1967. Frost resistance of grape varieties in relation to the conditions of hardening. Soviet Plant PhysioL 14:886-891. . Pratt, Charlotte. 1959. Radiation damage in shoot apices of Concord grape. Amer. J. Bot. 46:103-109. 1969. Freezing resistance in grape vines. Low Temp. Sci., Ser. B 27:125-144. . Stergios, B. G., and G. S. Howell. 1973. Evaluation of viability tests for cold stressed plants. J. Amer. Soc. Hort. Sci. 98:325-330. G. B. 1926. A study of the relative value of fruiting shoots arising from primary and secondary buds of the Concord grape. Proc. Amer. Soc. Hort. Sci. 23:293-296. HORTSCIENCE, VOL. 9(2), APRIL 1974 EP ILOGUE EPILOGUE Although Concord grapes have been important to Michigan agriculture for many years, relatively little has been done to promote an understanding of field viticulture in Michigan since N. L. Partridge developed the concept of balance pruning in 1925, and Larsen 32 31. developed nutritional tools. Consequently, the Michigan grape industry lags behind other viticultural states, notably New York and California, in grape culture development for the soils and climate of Michigan. Research activities in viticulture at Michigan State University since 1970 have revealed that this situation is both unjustified and unneces- sary. Indisputably, the climate in Michigan is not as favorable to vineyard establishment as it may be in other grape growing states. This assessment merely accentuates the need for a strong Michigan research program in this discipline, and constitutes a challenge rather than an obstacle. The field oriented studies presented in this dissertation were designed to pioneer that challenge for Michigan in a basic and forthright manner, and to establish a reasonable framework around which continued viticultural develoPment in Michigan can be guided. 117 118 There are several approaches to the undertaking of applied field research. One approach involves estab- lishing small and isolated field experiments with severely restricted purposes and objectives. I feel that this approach is unsatisfactory because just as the experiments are restrictive, so are the bits and pieces of information, which oftentimes are isolated and unrelated. The other approach, which is exemplified by the research undertaken for this dissertation, involves examining a spectrum of questions which evolve from a problem of wide interest and importance, such as the relationship between cold hardiness and productivity. The attempted resolution of such questions may produce not only pointed information, but also information which can be effectively integrated toward a broad and basic understanding of the problem. My dissertation problem was undertaken in an attempt to contribute to the basic understanding of cold hardiness and productivity patterns in Concord grape vines in Michigan, and to elucidate the basic nature of their relationship to each other. The type of relationship involving cultural stresses on Concord grape vine hardiness and productivity which I propose is summarized briefly in Figures 1 and 2. When Concord grape vines are culturally stressed, both vine hardiness and productivity are restricted (Fig. 1). Once both are restricted, hardiness and productivity 119 restrict each other. When vines suffer freeze injury, bud loss reduces fruitfulness and vine productivity. Reduced productivity, then, further reduces vine hardi- ness because vines with no fruit channel their energy reserves into vegetative growth, resulting in over- vigorous and insufficiently matured over-wintering canes. When good vineyard management (minimal cultural stress) is practiced, both vine hardiness and productivity improve (Fig. 2). In this situation, good hardiness and productivity complement each other, resulting in well- balanced vines (vegetative growth vs. fruit production) with optimal cropping conditions and fruit quality. 120 VITICULTURAL . VINE STRESSES - HARDINESS restrict Resulting in: Economic Loss + V . Reduced Fruit VINE Quality PRODUCTIVITY Fig. 1. Schematic representation of the relationship between viticultural stress and the vine hardi- ness - vine productivity complex in Concord grape. 120 VITICULTURAL . VINE STRESSES - HARDINESS restrict Resulting in: Economic Loss + v . Reduced Fruit VINE Quality PRODUCTIVITY Fig. 1. Schematic representation of the relationship between viticultural stress and the vine hardi- ness - vine productivity complex in Concord grape. 121 Fig. MINIW‘L VINE VITICULTURAL improves —D‘ HARDINESS STRESS improves Resulting in: Economic Gain + V Improved Fruit VINE Quality PRODUCTIVITY 2. Schematic representation of the relationship between minimal viticultural stress and the vine hardiness - vine productivity complex in Concord grape. APPENDICES APPENDIX A TREATMENT EFFECTS OF DEFOLIATION, PRUNING SEVERITY, AND CLUSTER THINNING ON THE PRODUCTIVITY OF Vitis labrusca L. var. CONCORD VINES FROM.A HIGH (ELEV. 277 m) AND A LOW (ELEV. 256 m) SITE IN SOUTHWESTERN MICHIGAN IN 1971, 1972, and 1973 Means are compared by the Tukey statistic at the 5% level of significance. Table l = 1971 Table 2 = 1971 Table 3 = 1972 Table 4 = 1972 Table 5 = 1973 Table 6 = 1973 122 mm.e ~.e~ am.e H.H bme.e a.m am>ma am a 3 m.»mxae aa.m ~.ea em.e a.ma me.e b.b emeeaau .ea + as .bmumaaomme ea.~ a.ab Hm.a e.ma ma.e m.a emeaaeu no: .ea + as .bmumaaomme ae.m m.~ea ab.e m.ma ao.o e.a wannabe .ea + em .bmumaaomme m aa.~ m.ma aa.a a.ma ma.e a.e amazes» boa .ea + em .bmumaaomme M aa.m o.ba m~.a m.aa ae.e ~.a emceaau .ea + as .bmumaaomme uoz ea.~ e.am be.~ m.ba ma.e b.~H emeeaeu boa .ea + ob .embmaaomme boz e~.m b.eaa ae.a b.ea Ha.e a.b baggage .ea + on .emumaaommb uoz Ne.m b.ma mb.a e.ea aa.e m.a coeeaeu boa .eH + an .bmbmaaomme uoz e~.o .m.z mm.e H.a no.0 m.~ Hm>ba am a 3 m.amxse ae.m b.eaa Na.e ~.ma ao.e a.b emeaaau .ea + as .bmumaaomwe mm.~ e.ea am.a a.ma aa.e e.ea emaeaeu no: .ea + ob .bmumaaomme m ae.m e.aea ma.e a.ma aa.e e.m emaeaeu .eH + on .emueaaomme 9 aa.~ m.ea ma.a H.ma aa.e b.e emeeaeu boa .oa + on .bmumaaomon H a~.m a.aa ma.a ~.aa ae.e m.e amazes» .ea + as .boubaaommb boz ba.m H.em em.a a.bH ma.e a.ea emeeaeu boa .ea + on .emumaaommb uoz ea.m m.mea ~a.e ~.ea Ha.e e.m emeeaeu .oa + em .bmubaaoumo boz ea.m m.me am.a o.ea ea.o a.e emaeaeu boa .ea + on .bmbmaaommb uoz Am. Ame Ammc meadow Amboe\mxe Ammo wufim mnwm ucoaummua muflm muumm “mumsao ummsm mabsaom pagan baoaw .mwmmn mcw> you o no mum sm>wm “mm H av modam> smofi one .Hhma cw savanna: sumumwznusOm cw muwm AE emu .>0Hmv 30H m can A8 bum .>mH0v gown m Eonm mocwb manna whoosoo mo aufi>fluos©oum .HI¢ manna 123 w 3 mlnwvnfirfi ¢.m ~m.o m.ma mm.o m.um Hm>ma mm >.om om.o N.Hm mv.a N.mh omscwnu .oa + om .omumwaommo o.vm mm.a o.mh mm.a m.mva omcswnu pom .OH + om .omumaaommo e.mm em.o m.mm mb.H e.be emceaau .oa + on .bmumaaomma T H.mm Ho.m >.mm hn.a m.naa omscflnu no: .oH + on .omuMHHOMTQ m w.om em.o m.mh N¢.H m.wh posswnp .oa + co .UTHMflHOMTo uoz b.m~ hm.H o.Hm me.a m.mma cognac“ no: .oH + om .omumwaommp uoz m.vm mm.o m.wm mm.H m.vm pmssflau .oH + om .pmuMHHOMTG uoz m.Hm mo.m H.~m mw.a o.moH posses» uoc .oa + om .oouMflHommo uoz .m.z Nb.e o.ma ae.e e.em Hmema mm a 3 m.»mxse m.mm Hm.o b.mh ~m.a ~.mm posswnu .oa + co .pmpmHHOMOQ a.~m aa.a a.ea mm.a N.eea emeeaeu boa .ea + as .bbbbaaomwe m ~.mm oa.a «.mv mm.H m.am posswnu .oH + om .omumeOMTQ m m.am vw.a m.mv hm.H o.am posses» “on .oH + on .omumflaommo ~.om hm.o o.mh Hm.H m.>m pmcswnu .oH + om .pmomfiaomwp uoz m.hm >>.H m.on om.a o.¢NH Uwscwsu no: .OH + om .UTHMRHOMTG #oz m.~m mo.H v.om H¢.H b.mm ooccfinu .oa + on .omumeOMTp uoz n.om om.H m.Hm mv.a o.aoa omscwnu uos .oa + om .omumeOMTw uoz umum5a0\ moos\ vmswmumm Ava Hmumsao mwwuumm nmmmsao mmpoz .oz muam mca> .oz usmfiumwua muwm oz oz . . .mwmmn mcw> Hum m :0 mum cm>Hm Amm” u av mmsHm> some 039 .Hhma cw smmwnowz cumummznwsom CH muww as wmm .>0H0v 30H m can AS hum .>0Hmv swan m Eoum mmaw> mmmnm ouoosou mo muw>fluoscoum .mlm OHQMB 123 w 3 m.%wun§B v.m mm.o m.mH mm.o m.hm Hm>ma mm b.om om.o N.Hm mv.H N.Mh cognac» .oa + ow .wwumwaomma o.v~ mm.H o.mb m~.H m.mvH posses“ no: .oa + om .GTHMflHOMTQ «.mm vm.o m.mm mm.a h.wv omssflnu .OH + on epmumwaommo T H.m~ Ho.m h.mm bb.a m.hHH omssflnu nos .oH + on .Umum«H0mmo m v.om em.o m.mh N¢.H m.vn posswnu .OH + co .omumwaoumo uoz h.m~ hm.a o.Hm av.H m.mmH pmscflgu nos .0H + om .omumwaommc uoz m.vm mm.o m.vm mm.H m.vm pandas» .OH + om .pmumaaommo uoz m.Hm mo.~ H.Nm mv.H o.moa Umcsflnu you .oH + on .GTHMAHOMTU uoz .m.z Nb.e o.ma ae.e e.em Hm>ma am a 3 m.mmxsa a.bm Hm.e e.ma ~m.a «.mb emceaeu .ea + as .bmubaaommo n.~m nv.a ~.v> mm.H «.moa posses» uos .oH + om .omum«H0mmo m ~.mm oH.H «.mw mm.a m.Hm posses» .ca + om .pmpmHHOMTQ m m.am wm.a m.mv hm.H o.am posses» uo: .oa + on .wmumHHOMTO N.om hm.o o.mh Hm.H m.>m omcswnu .oa + om .omumaHOMTc uoz m.hN wn.a m.o> om.H o.v~a posswnu uo: .0H + om .oTuMflHommp uoz m.mm mo.H v.om He.a n.mm omscwnu .0H + om .oOHMflHOMTp uoz >.om mm.a m.Hm N¢.H o.aoa cognac» uoc .oH + om epmumfiaommo uoz Hmumsao\ moos\ msamumm mm HmumsHU wwwnnmm HmwmsHU mwoow .oz mudw mwa> .oz uswfiumwna wuwm 02 oz . . .mflmmn msw> you b so mum cm>flm Amm” u av mmsHm> coma one .Hhma cw savanna: cumummznusom cw wuwm AE mmm .>0Hov 30H m can as new .>0Hmv amen m Scum mmaw> mmmum pucocoo mo huw>auosvoum .~|¢ manna 124 mm.e .m.z am.o a.e me.e a.m Hm>ma am a 3 m.>mxse mm.~ m.maa aa.e a.~a me.e e.b emeeaeu .ea + as .emumaaommo ab.~ b.ama ab.e m.aa ae.e m.m emaeaab boa .ea + as .emumaaomme am.~ a.m~a ea.e a.aa aa.e m.m omeeaau .ea + em .bmumaaoume ”l «mg cad $5 92 2.0 a6 emeeafi nos .3 + on 6333me m ae.m m.m~a mb.a «.ma ea.e m.ea ceases» .ea + as .embmaaomme uoz ma.m m.eea mm.~ e.ma -.e e.ba cmeeaeu boa .OH + as .emumaaommb uoz bH.m b.maa em.a m.ma ea.e m.a bmaeabu .OH + on .emuaaaommb boz aa.m b.maa me.~ «.ma e~.e m.ma baggage no: .ea + em .bbumaaomme uoz ~m.e H.me mm.e e.e ee.e a.m Hm>ma am a 3 m.3mxsa mm.~ b.eoa Nb.e b.aa mo.e a.e wannabe .ea + ob .emumaaommo ab.~ m.ba ma.e m.~a ea.e a.b cabbage boa .ea + ob .emumaaomwn "a ma.~ a.a~a eb.e a.~a Ha.e a.e emeeaeu .ea + on .bmbaaaomme m“ me.m a.~ma Hm.o b.~a ma.e e.b emeeabu boa .ea + on .emumaaommo "a m~.m ee.e~a He.a a.ma ea.e e.ea . emeeaab .ea + ob .bbbbaaommb uoz m~.m b.aea mo.~ e.ma ma.e «.ma bungee» no: .ea + as .eoumaaoumb boz ma.m e.mea ea.a ~.ba ba.e b.m emeeaeb .ea + em .ebumaaomme uoz m~.m a.~aa mb.a a.ba -.e m.ea boeeaau uoa .ea + on .bmumaaommb uoz Ame Awe flame mbaaom Imboe use “use Team Team ubmsm mansaom wanna babes ucmsummue muam muumm kumsau .mflmmn msfl> Hum m co mum sm>wm awn u av mosam> some one .mea GM cmmflnoflz sumumo3£u50m :H Guam .8 mmm .>mamv 30H m can as bum .>mamv an“: m Eonm mwcw> momum ouoocou mo muw>wuospoum .mlm wanna 125 .m.z am.e a.~a em.e «.mm Hmema am a 3 m.»mxaa m.oe me.o m.He HH.H e.mm emeeaau .oa + as .bmumaaomme m.ma ma.e e.ab ea.e «.me bmeeaeu no: .oa + em .bbbmaaomma e.ea ma.e b.ma ma.a m.ee emaeaau .eH + on .bmumaaommo T m.mm bH.H b.me aa.e e.om emacabu so: .ea + em .boubaaomwe m b.oe bH.a H.me m~.a o.mm abscess .ea + ob .bmubaaommb uoz «.mm ae.~ e.ae H~.H e.aea emceaau boa .ea + as .bmumaaommb uoz a.ee am.a o.aa m~.H a.ae embeaau .oa + on .bmumaaommb uoz e.am ee.~ b.be am.a e.maa emceaeu no: .ea + on .bmumaaommb uoz .m.z am.o m.mH ab.o H.om Hm>ma am e 3 m.mmxae e.mm ee.o a.ea e~.H «.mm emcaaau .ea + om .bmbbaaomme ~.em me.a b.ab ea.e b.aa commas» boa .ea + as .embmaaomme m m.ae em.e e.bv mm.a ~.ea bmeeaau .oa + on .bmubaaomma m a.oe Hm.a a.ma eo.H H.mm emaeabu no: .oa + om .empmaaommo a.am ea.a a.aa am.H ~.ea emaeaeu .oa + as .bmumaaommb uoz a.am ab.a e.ba a~.a a.e~a emaeanu no: .eH + ob .bbbbaaomob uoz H.me oa.a a.mm eb.H e.ob emeeaau .ea + em .bbbbaaommb uoz o.mm ea.a m.em mm.a «.mm emceaau uoc .oH + om .bmumaaommb uoz Houm5H0\ moos\ pmswmumm Ava Hmumsau mWMMHTm HmwMMHU mmooz .oz mNflm mcw> .oz usosummue muwm .mwmmn mcw> mom b so mum sm>flm Amm u av mmsHm> some one .tha ca nmmflnowz sumummznusom ca open As mmm .>mamv 30H M van As new .>0Hmv now: m Eoum mmaw> mmmum Uuoosoo mo muw>wposuoum .vl4 manna 126 .m.z .m.z .m.z .m.z .m.z me.m Hm>ma «m e 3 m.mmxba mm.~ o.mea em.e b.~a ao.o -.e emeeaau .ea + as .bmumaaomme ab.~ a.~oa mm.o a.aa me.e am.a emeeaau no: .eH + ob .embmaaomme em.~ H.ema ma.o b.~H eH.e mm.m emanaau .ea + on .emubaaomma m ma.~ m.mma mm.e m.NH ma.o me.e emeeaeu no: .ea + om .bmumaaomma M em.~ m.mma bH.H a.ba ao.e .mm.b emceaau .oa + ob .bmumaaommb uoz aa.~ e.moa mm.a e.ba ma.o em.a emeeaeu uoc .OH + as .bmumaaombb uoz be.~ m.ama me.a m.ba ea.e aa.b emceaau .ea + on .bmumaaommb uoz aa.~ o.bma ~e.a a.ba ma.e aa.m amazes» no: .ea + em .bmbmaaomme uoz -.e a.a~ be.e .m.z mo.e mm.~ am>ma am a 3 m.»mxae wa.~ o.mea mm.e a.aa ~H.e m.m wannabe .ea + as .bmumaaomme ab.~ e.ab aa.e m.HH Ha.o e.b emeeaeu no: .oa + as .bmumaaomme H ma.~ m.a~a em.e «.ma ~a.e m.e wannabe .ea + em .bmbmaaomme m ae.~ .bm ee.o m.~a ma.e a.m embeaau uoc .eH + on .bmumaaomme H eH.m a.aaa mm.a e.ba ma.o ~.a emceaau .ea + as .bmumaaommb uoz ee.m a.ma ae.~ a.ba ma.e e.~a bmeeaeu no: .ea + as .bbumaaommb uoz me.m e.oma ~m.H m.ba mH.o a.» amenabu .oa + om .bmumaaommb uoz mo.m e.baa be.~ e.ba m~.e m.~H bmaeabu pom .ea + on .bmubaaommb uoz “me any AmM m “How A0 on mm mm muam muam ummwm mamsaom magma V bflmaw pewsubmua ouam mnnmm Hmumsau .mmosmummmww uGMOHMflsmHm 02 u uommmo usmfiumonu mum mmsHm> .>mamv 30H b one as new .3mamv sown m soum mmcw> mmmum ouoocou mo hufl>apoc©oum .mwmmn msw> mom m :0 Amm u .mbma aw cmmflnowz sumummsnusom aw muflm AE mmm av momma .mld manna 127 m.aa me.e .m.z .m.z a.b~ Hm>ma mm a 3 m.»mxse m.ae ab.e m.mm aa.o m.om emceabu .ea + as .bmumaaombe «.mm Hm.e m.mm ae.e m.me emecaeu no: .oa + ob .meMaHommn m.mm eo.o e.mm ee.e e.m~ emceaau .OH + om .bmumaaomma T a.em ea.o e.mm mb.o a.am ebcaaau boa .OH + om .bmumaaommo o a.ee Ha.e m.ma me.a ,e.bm emeeaeb .oa + as .bmumaaommb uoz M e.em Hm.H m.eb ee.a m.em emaeaeu boa .oa + 0b .bbumaHoMMb uoz e.om me.a m.~m mm.a «.me bmeeabu .oa + om .bmumaaommb uoz m.ma b~.H m.em me.a m.ab amazes» boa .oa + em .bbumaaommb uoz e.b ma.e .m.z .m.z e.b~ am>ma am e 3 m.amxae m.mm om.e m.em mm.e m.am beggar» .OH + as .bmumaaomma e.m~ He.a m.Hm mm.e e.bm wannabe uoc .oa + ob .bmumaaommo mm m.ae aa.e m.mm em.o m.mm abscess .ea + em .bmumaaoumo m H.Hm ma.a H.mm we.H a.mb bwccabu no: .oa + on .bmumaaomme H.bm oa.a «.me Ha.H a.mm abscess .oa + ob .bmumaaommb uoz m.am em.a e.ae me.a b.~ma emeeaeu no: .ea + ob .bmumaHoLMb boz o.me NH.H a.bm aa.a m.eb boeeabu .ea + on .bmumaaommb uoz a.am He.~ H.bm bb.a a.~HH beggar» no: .oa + em .bmumaH0mmb uoz HmumsH0\ moos\ Umcamumm Amxv umumsau mmfiuumm Hmumsau . . . ucmfiummhe .oz .02 mwooz oz Guam mcw> oz wwwm .mmosmummmwp unmowMHcmwm 02 u .m.z .mflmmn 0sH> Mom m :0 “mm H av mawaflbflflflflflflflflflflu uommmm unusummuu mum mosaw> .mnma cw cmmflnowz cumummsnusOm ca ouflm as .3mamv 30H b one as new .>meC amen m scum moca> mamum cuoocou mo >ya>auosvwmm . . m o APPENDIX B PILOT STUDIES ON THE HARDINESS AND PRODUCTIVITY OF PRIMARY AND SECONDARY BUDS OF CONCORD GRAPEVINES CONDUCTED IN SOUTHWESTERN MICHIGAN IN 1972 AND 1973 APPENDIX B STUDIES ON THE HARDINESS AND PRODUCTIVITY OF PRIMARY AND SECONDARY BUDS OF CONCORD GRAPEVINES (Basil G. Stergios, Gordon S. Howell, and S. S. Stackhouse) In studies conducted in 1971 and 1972 of site effects on dehardening of Concord vines we discovered that during the late stages of dehardening that hardiness dif- ferences as large as 10°C existed between primary and secondary buds. Of equal importance is the fact that the secondary is less productive than the primary. We became interested in examining this hardiness-production differential since it has considerable implications on both the economics of Concord production and the control of bud hardiness in grapevines. In years such as 1973 it is of considerable interest to know how to improve the productivity of the secondary or, considering another route, how to improve the hardiness of the primary and reduce loss to low tem- perature stress. In 1972 a pilot study was initiated to gain infor- mation on the influence of the primary bud and develOping cane on the growth and productivity of the secondary bud. The vines were trained to 4-Arm Kniffen and three treat- ments were chosen: 128 129 1. Normal vines (controI); 2. Primary bud removed at alternate nodes; 3. Primary bud removed at each node. Primaries were removed at bud swell (May 14). The pro- ductivity data collected are presented in Table B-1 and growth measurements are presented in Figure B-l. It was necessary to develop a technique to selec- tively kill primary buds at various times during the dor- mant season. Our method of accomplishing this and the criteria for evaluating injury is presented in Basil Stergios' Ph.D. dissertation. In the spring of 1973 the liquid N2 apparatus (demonstrated last year) was used on March 15 to kill dormant primary buds and another treatment, as in 1972, was primary bud removal at bud swell (April 30). These data are presented in Table B-2 and in Figures B-2,A and B-2,B. In the fall of 1973 a full-scale experiment was undertaken at the Sodus Research Station to test the effect of primary bud loss at different times of the dormant season on the hardiness and productivity of secondary buds. Our first treatment was November 15, 1973. On February 12, we again applied a puncture-kill treatment and collected samples for evaluation of both field hardiness and ability to take cold stress in our 130 laboratory freezer apparatus. All the data are not in and it would be premature to comment yet, but we feel that we now have developed tools which are going to allow us to penetrate to the basic relationships of hardiness and productivity of the Concord grape bud. The effect of primary bud growth on development of secondary bud is rather straightforward. Through some mechanism, likely apical dominance, the primary controls the development and growth of the secondary shoot. Does this mechanism operate in the dormant bud? This year's data from Sodus should provide the answer. What effect does the primary exert on yield and fruit quality? Table B-1 provides some insights on that. The primary shoot is far more productive than any secondary shoot. That is not all of the answer, however. The primary also reduces berry size and number of clusters of secondary buds even when removed as late as May l4--long after most authorities have considered such factors already anatomically determined. This is exciting information which suggests that we may be able to alter the productivity of secondary buds much later than pre- viously believed. In 1973 the plots on GDC trained vines and nodes at which primaries grew produced no secondary shoots. That is why that treatment is not represented in the 131 vine growth data in Figure B-2 and the productivity data in Table B-2. The interesting thing about the data in Figure B-2 is the difference time of primary loss made on secondary shoot growth. If the primary was killed on March 15 secondary shoots grew equally well. If the kill date was April 30 the presence of secondary shoots at alternate nodes repressed the development of all_secondary shoots to a significant degree. The productivity data from 1973 did not follow the same trend. The poorest treatment was secondary shoots which had a primary at alternate nodes on the early treatment date. Although the field variability was great and the clusters/node figure is not statisti- cally different I strongly feel that it is as Nelson Shaulis would say "viticulturally significant." We are confident that we have an experiment presently underway that will effectively test the validity of our feelings. 132 “usmmmum mumfiflnmv am.ma 0mm.o om.mom Umpo om.m amm.o mumczoomm AHHm3m tam um . . . . . . mmooz mumcumua¢ um hubocoomw Aaam3m can an ea.ba bae.o bo.maa bm.a be.m bam.o em>osmm mumsaumv huntcoomm . . . . . . “Houucouv awe ma bob 0 pm vua Tm N nm N Mme o noonm wumeflum mpwaom moo: WWW woos gunmen\E Amoos\mmv so mom mandaom \Hmmsm mm Hmummwu \mumumoao ouam muumm came» u Eu 9 .mo. v m sons usmummmwo hausmowmwsmwm mum mammz .mhma .Hmnouoo ca omum0>umn mmsw>mmmum whoosoo .Umsfimuu Mdle .omcsum woodmamn mo wufibwuosooum noonm mumomoomm so HM>OEmH can MHMEHHQ mo uomwmm .alm THAMB 133 Aom HHHQ4 EOHM mmpoz mpmsnmuad um cm.ma bom.o hm.Hm pH.H mv.m nam.o ucmmmum mamaaumv mnmosqowm xom Hanna co ma.ba bme.o be.m~ ba.a Hm.m bem.e bm>osmm mumsauev humpsoomm Ana comm: Eoum ba.ma oom.e bm.am be.e ma.m bem.o mmmmwmwwmemwwwmbww mamoaqomm Ama nouns :0 em.ma nmm.o n~.bm n~.H um.m nwm.o om>oEmm mumeHmv mumosoomm O O O O O O AHOHHGOUV ma ma wow o be «a Mm m mm m Maw o poonm mumfiflum moflaom moo: wwwm woos Ammumn\mv Amooc\mxv so mwh mansaom \Hmmsm mm Hmummao \mumumsao mnwm human pawww 9 Eu 9 .mo. v m smnz usmuwmmwo mHuGMOHMHcmflm mum memos .mhma .Hmnfimummm a“ omumm>umn mmsw>mmmum choocoo .pmcfimuu 000 .cwssnm Umocmamn mo huabfluosooum poonm mumosoomm so Hm>osmu can MHMEHHQ mo uommmm .mnm magma Fig. B-l. 134 EffeCtS 0f Primary bud removal on secondary shoot growth from May 16 to June 16, 1972. Primary buds were removed May 14, 1972. Confidence intervals compare treatment means. 135 I 90- OECONOARY SHOOT OROIYTH - I97: — WITH PRIMARY PRESENT EVERY NODE ---WITH PRIMARY ABSENT EVERY OTHER NOOE 80- . ----W|TH PRIMARY ABSENT EVERY NODE _- , . l ' l W95 - 95% CONFIDENCE .' I! 2 .. I TO- ., I 3 so- 0 v I '; o 50- m (9 v '— 0 g 40- a) 3 g ID 30‘ 20- IO' ' JUNE I6 Figure B-l Fig. B-2. 136 Effects of primary bud removal on secondary shoot growth of Concord grape vines from May 13 to July 4, 1974. A--primary buds killed March 15, 1973. B--primary buds killed April 30, 1973. Confidence intervals compare treatment means 0 137 Figure B-2 APPENDIX C NUTRIENT LEVELS OF Vitis labrusca L. var. CONCORD VINES BASED ON QUANTITATIVE ANALYSIS OF LEAF PETIOLES SAMPLED IN AUGUST, 1971 FROM A HIGH (ELEV. 277 m) AND A LOW (ELEV. 256 m) SITE IN SOUTHWESTERN MICHIGAN Table 1 shows main effect means,.and Table 2 shows treatment effect means. 138 .H0>0H mm 0 00:0000flcmflm u % N.0N «00.5 0.0a N.000 05.0 «N¢.H a"0.00m mm.0 Nm.0 «05.0 UOGflHfiB #OZ 0.5m 00.0 H.0H m.vH0 50.0 «m.H 5.00H NN.0 50.0 00.0 UOGGflfiB 0.5m 00.0 0.0a 5.H00 00.0 0m.H 0.0HN NN.0 00.0 00.0 umcfium 0H + 00 N.0N R00.5 0.5a. 0.NHO 00.0 0m.H H.N¢N mm.0 00.0 50.0 UOGDHA 0H + 00 v.50 5H.5 «5.0a 0.v~0 H0.0 mm.H H.000 «0~.o Hm.0 m0.o 0000flaom00 0.0m 00.0 0.0a 5.000 R05.0 R¢¢.H 0.NNN 0H.0 50.0 00.0 ©0u0HHOMOQ “Oz 0.0m 0.0H 5.NN 0.050 R00.0 «5m.H 0.500 5H.0 HH.H 50.0 GOGGflSB uoz 0.0m 0.0 .0.0N 0.0v0 v0.0 5N.H 0.000 0H.0 VN.H 00.0 UOGGHSB 0.0m 0.0H m.HN N.vv0 00.0 vm.H 0.Hmm 0H.0 0H.H «00.0 U0G§Hm 0H + 00 v.0N H.0H H.NN 0.500 «0.0 00.H 0.0mm 5H.0 0H.H v0.0 wmcuum 0H + 00 0.0m H.0H R0.0m N.vv0 00.0 5N.H 0.000 0H.0 NH.H 00.0 OOuMflHOm0Q 0.5m m.0a 0.ma v.000 v0.0 «5m.H 0.5mm 5H.o NN.H 50.0 U0umaaoM0a #02 m 50 00 a: 02 mo 02 m M z 0Howu0m ca us0E0Hm no 800 0cm us0ou0m mabaanb> 00am .m0Hoflu0m 000a mo .um0u 030 How GOAHHHE H00 muumm cam 02 .00 How us0ou0m mm s0>wm msm0E #00000 CAME 0H0 m0sam> 0>flumuwusmsv no 00mmn m0sw> 0mmum choocou mo H5ma .umsmsm sH 0H0>0H .m .M .2 mwmhamcm us0fluusz .HIU OHAMB 139 0.H0 0.HH m.mm m.m 0.00 0N0 00.0 mH.H omm 0H.0 ma.H 00.0 00ssw£u 0H + on ©0umaaow0n 5.05 m.0a 0.0m 0.HH 0.0m 550 00.0 Hm.a mum 5H.0 ma.a 00.0 U0scwnu #0: 0H + on 00umaaou0o 0.50 0.0a 0.5m 0.0a 0.0a H00 H0.0 0m.H mam 0H.0 0N.H 50.0 00csfinu 0H + 00 U0umwaom00 uoz 0.H0 0.0a 0.5m 5.0a 0.0a 0H0 50.0 mv.a 0am 0H.0 v~.H «5.0 U0sawnu uoc "w 3 + as m 00umwaom0c #02 0.50 0.0a 0.5m 0.0 0.0H 000 50.0 0m.H 05m 0H.0 0N.H 00.0 00csflnu 0H + on p0umflaow00 uoz m.¢0 0.0a 0.5m N.HH 0.0m 005 H5.0 0¢.H mmm 0H.0 mH.H 00.0 ©0scfl£u #0: 0H + on 00umflaom0c #02 2 cu m so mm a: 02 mo «.2 A x z us0Eum0HB 0000 0Howu0m cw us0E0Hm mo Ema 0:0 uc0ou0m .m0os0u0mmw0 unmowmwsmflm oz u .0.2 .um0H 050 How 0Howumm cw sOHHHwE H00 muumm 0:0 02 .00 .m .M .2 How 0H0Hu0m ca us0ou0m 0H0 s0>flm “0 u c0 m0sam> am0fi 0:9 .00H0Hu0m 000a mo mammamcm 0>flumuwusmsv so @0003 m0sw> 0mmum whoocoo mo H5ma .umnms< ca 0H0>0H pc0fiuusz .NIU 0Hn09 140 0.00 5.05 0.50 0.00 0.00 0.00 0.50 5.00 H.0N «0.0 00.0 0v.0 00.0 0.vH 0.0a 0.0a 0.0a 000 000 000 000 H5.0 00.0 55.0. 05.0 H0.H H0.H Hv.H vv.a 05H 0mm HHN 050 00.0 0H.0 0H.0 0H.0 55.0 00.0 00.0 00.H 00.0 H5.0 00.0 00.0 oweeaeu ea + as bbbbaaoMbb boz 00scwnu pom ea + as emumaaommb uoz umeeaeu ea + om emumaaommb uoz 00cswnu #0: 0H + 00 0000Haom00 uoz MOT .m.z 0.H0 0.0m .m.z 0.0 0.0a 0.00 005 00.0 00.0 00.0 H0.0 0N.H 00.H 00H 000 500 .m.z 00.0 0H.0 .m.z 00.H N0.0 HH.0 50.0 00.0 H0>0H mm 0 3 0.00:59 00ccflnu 0H + 00 00umwaom0o U0ssw£u was as + as emumaaomme HOIH ad GN 50 Oh GE 0: 00 02 mHoapmm ca newsman no 800 0:0 uc0ou0m unmsummua {I uwscwuzou abaa .mno magma 141 0.5H 0.50 0.00 0.H5 0.0m 0.0a 0.HN 0.Hv v.5N 0.50 00.0 00.0 00.0 00.0 NH.0H 0.Hm 0N0 00v H00 50.0 50.0 00.0 00.0 H0.0 NN.0 0N.H ~0.H 0N.H H0.H HNH «mm 500 00a 00m 0H.0 5N.0 0N.0 00.0 H0.0 55.0 00.0 H0.H NH.0 50.0 00.0 00.0 05.0 H0>OH wm w 3 m.%0¥§9 emeaaeu ea + as bmpmaaomme U0cswnu no: ea + as emueaaomme emanaeu ea + em bmumaaomme emeeaeu boa 0H + 00 U0umwaom0a MOT H4 RN 50 0h as ms 00 0Z 0Howu0m cw us080Hm no 500 0cm uc0ou0m us0fium0ua muam ©0scauaoo .NIU manna APPENDIX D MEAN mg STARCH/g DRIED y_i_t_i_§_ labrusca L. var. CONCORD BARK AND WOOD TISSUE FROM HIGH AND LOW SITE, HIGH AND LOW TRELLISED STEMS SAMPLED DURING ACCLI- MATION AND DEACCLIMATION IN 1971, 1972, AND 1973 IN SOUTHWESTERN MICHIGAN gill I —-_._l 142 H500. _ Hm0.0 H . 000 n 0smmwu 0\£ou0nm 08 me I no mm.ma 5m.a5 ea.am a5.em emeeaeu .ea + em .emumaaomme ee.5m 55.55 mm.a5 ~5.am emeeaeu uoa .ea + em .bmumfiaomma ea.am 55.05 ma.b5 ~m.me emeeaeu .ea + om .0mumaaomme He.eea mm.m5 5b.eea «5.5m emceaeu uoc .eH + em .eoubaaomme Ha.mma mm.5ea ma.mma ma.ma emanabu .ea + om .0mumaaommc uoz me.maa He.m~H mm.mma em.bma emaeaeu pee .ea + em .0mubaaommb uoz mm.aaa ma.aa ea.baa om.ma omceaau .oa + on .0mubaaommb uoz 55.e~a mm.em H5.mma mm.ma cmaeflbp boa .ea + em .0wumaaommu 002 0003 xn0m mcw>wn 0003 xu0m 00H>HA mEAMAaamue souuom mcflmflaa0ua 009 u00au00ua n xn0m 00H>Hq .0000 000 E0H5x n 0003 .E0oanm 000 ESHQE0U .0000 00000H0IHH0 HH03 .0000 0 scum H50H .m H0nouoo 00 00uo0aaoo 0500Hu E000 0m0u0 uuooqou 00wn0 0\£ou0um 08 0002 .HIQ 0HQ0B H 0000. H 143 ”00.0 5H0. I 00000 n 0smmwu 0\£0H0um 08 0.00 0.00 0.H0 v.05 00ssflnu .0H + .00u0flaom0a H.50H 0.HOH 0.00H 0.00H 0000000 000 .0H + .00u0waom0o «.50 m.mm m.mma «.mm omeeaau .ea + .0mumaaomma 5.00 0.0NH H.00H 0.00 0000000 no: .0H + .00u0waom0a 0.00 0.05 0.5ma 0.05 0000H00 .0H + 00 .00u0waom00 #02 0.00 ¢.H0 0.-H H.0ma 00000:» no: .0H + 00 .00u0flaom00 uoz a.moa m.mea, ~.-H m.~ma owceaeu .ea + .0mumaaommc uoz 0.00H 0.50 0.00 0.00 0000000 000 .0H + .00u0flaom00 #02 0003 xu0m mcw>wq 0003 Mu0m 00H>flq #:0Eu00ua meamaaamue Eouuom. 00H0HHH0HB mos mcfl>wq .zuflm 000 E0Hhx n 0003 .E0oanm 0:0 ESHQE0O Mn0m .0uflm 00000HUIHH0 HH03 .nmfln 0 Eonm H50H .0 H0nfi0>oz do 00Oo0aaou 0000a» 8000 0m0u0 UHOOQOU 00HH0 0\nou0um 0E :00: .NIO OHQMB 144 Hmm.0 H 0b00. 5000. + 00000 “— " mammflp 0000 on u I 0\£on00m 08 I m.ae m.aa «.50 cmeeHeu .OH + om .0000000000 0.0a e.m5 m.m5 m.e5 umeeflau 00a .oa + em .mmumflaommn m.oo0 m.~ea m.m00 m.am0 emeefleu .00 + on .0000000000 m.o~ e.mm m.mHH o.55 umceHau 0oz .oa + om .0000000000 m.am 5.05 5.05 a.a5 nmeeaau .00 + om .0000000000 uoz v.5aa 5.05 e.5e0 0.5m0 emaeHnu 00: .ea + on .0000000000 002 I I I I cmeq000 .00 + on .0000000000 002 ~.ma «.0a m.m00 m.e~0 emee0eu 00c .ea + on .0000000000 0oz 0003 £000 000>0q 0003 x000 0GH>HA mafimflaamue E00000 0000000009 008 000500009 000>0q .0000 000 E00»% n 0003 .E0OH00 000 ESHAE0O u #000 .0000 00000H0IHH0 000000 .30H 0 8000 H500 .0 H0QE0>oz no 000000000 000000 E000 00000 0uoocou 00000 0\£ou000 08 0002 700000 .NIQ 0Hn08 H0m.0 Hllmwbo. H u 000000 0\£0H000 0E 145 00. I 00000 00.05 00.00 00.00 00.05 0000000 .00 + 00 .0000000000 00.00 00.05 00.00 «0.00 0000000 000 .00 + 00 .0000000000 ~m.~w e5.ee me.om mm.mm cmceflnu .eH + on .0000000000 00.00 00.00 00.50 00.00 0000000 000 .00 + 00 .0000000000 00.05 00.00 00.00 00.00 0000000 .00 + 00 .0000000000 002 50.00 me.mm 5H.~m am.om cmee0e0 uoe .ea +.em .00000Hommu 002 50.05 «0.000 00.000 00.00 0000000 .00 + 00 .0000000000 002 50.00 05.50 00.05 00.00 0000000 000 .00 + om .0000000000 002 0003 0000 000>00 0003 0000 000>00 000E00009 0000000009 E00000 0000000009 009 .E00000 000 E000E00 n 0000 ma0>0q .eufim 0am Emamx n 0003 .0000 eoEHmucIHHM 0003 .0000 0 E000 0500 .00 H00E000a no 000000000 050000 E000 00000 0000000 00000 0\000000 0E :00: .mIQ 00009 146 000.0 0mmmwmpwmmmm_ n 000000 m\000000 08 00.00 00.00 00.00 00.00 0000000 .00 + o0 .000000o000 50.00 00.00 05.00 05.00 0000000 000 .00 + 00 .0000000000 00.00 05.00 00.00 05.00 0000000 .00 + 00 .0000000000 00.00 50.00 00.00 50.05 0000000 000 .00 + 00 .0000000000 00.00 00.00 00.000 00.00 0000000 .00 + 00 .0000000000 002 00.00 00.05 00.00 00.00 0000000 000 .00 + 00 .0000000000 002 00.00 00.00 00.000 00.00 0000000 .00 + on .0000000000 002 00.05 00.00 00.000 0N.55 0000000 000 .00 + 00 .0000000000 002 0003 0000 000>00 0003 0000 m00>00 000800009 0000000009 800000 0000000009 009 .800000 000Imw00800 n 0000 m00>00 .0000 000 800mx " @003 ompflm UmGflMHUIHHM %HHOOQ ~3OH M EOHM HhmH .00 00080000 00 000000000 000000 8000 00000 0000000 00000 0\000000 08 0002 0.00000 .le 00909 smoo. _ :3 H . .. hmmo ommno n mammfiu m\£OHMUm me 147 m.am m.am 5.5H h.wv coacflnu .oa + om .cmuMHHommn b.ou m.mw n.mv m.mm nmcnflnu no: .oa + co .cmuMflHomma . n n u omccflsp .oH + on .cmumwaomma : u u . omgafinu uoc .oa + on .omuMfiHomoa . : m.mh m.~m owccflnu ~oa + om .cmumflaommo poz m.moa ~.vm «.mm m.Hw cmccflnu no: .oa + co .cm»MHHommu uoz u n u n emacflnu .OH + om .cmumwaommc uoz u a u u vmccflnu no: .oa + on .wmuMHHommc uoz @003 xnmm mcw>fiq @003 xumm mcfl>fiq unweummna mnflmflaamus soupom mcwmflaawua mos .Emoanm can Esfinfimo n xumm mcfl>flq .nuwm wan Smamx u @003 .muwm cmcwmuulnwm HH03 .amwn m Scum tha .mw scum: no cmuomaaoo mammwv Emum mmmum choocou omwuo m\£oumum ma Gum: .vla magma 148 .mm; TILumloIohlllL hmmo. I omma mammau mumc on u I m\£oumum m8 o m.mHH «.mp n m.mm cmccflnu .oa + om .cmuMHHomma m.mo H.am m.mm m.¢m uoacflau you .oH + om .umuMflHommo n u u I umccflnu .oH + on .nmuMfiHommo I I I u nmaaflnu uoa .oH + on .umumaaommo m.HHH H.mn m.H~H c.5m umcnasu .oa + om .omuMflHommu uoz u m.~oa «.moa c.m> cmqaflnu no: .oa + om .umuMfiHommo uoz I I I n vaccflau .OH + on .wmumflaommo uoz I I I I vmcnwnu no: .oa + om .UwumeOva #02 @003 xnmm mcfl>flq @003 xnmm ocw>fiq unmaummua mcflmflaamua aouuom mcflmwaawna moa .nUHm 6am Emaax " @003 .EmoHnm wan Eswnfimo u xumm mcw>flq .muwm cmcwmuolufim wauoom .30H m Eoum thH .mm noun: :0 vmuomaaoo mammwu Emum mmmum choocou vmwun m\noumum ma cum: A.u:oov .wln wanna Hmm._ Hmawmwmm0mmmn H u mummflu m\n0Hmum ma 149 0 «.mm «.mm «.mm «.mm wchflnu .oa + co .umumflaomma cram o.mm m.$ «.mh umccflfi you .3 + ow .wmumflomma v.31” m.mm «.3 mém cmncfifi .3 + om .vaMHHommo mime m.mv m.mm 0.3 wchflfi nos .3 + om .wmuMflHomma h.mm >.mma «.mm m.HNH cmacflnu .OH + co .omumflaommw uoz «.mm H.mv méoa 5.8 @9235 Hyou .3 + om .vmumwaommv u\oz N.Hb H.mh m.mm o.mv wmccflsu .OH + om .UmuMHHommU uoz H.mv o.mm h.Hm h.mh dmccwau no: ~oH + om .UmpMflHommU #02 @003 xnmm mcw>flq @003 xnmm mcwbwq 1| ucmfiumwua mcflmaaaoue Eouuom mcflmflaamua mos .Emoanm can Edfinsmo u xnmm maw>aq .nuHm cam Emahx n @003 .muwm wmcwmumlnwm Ham3 .nmwz.m Scum mhma .mH HHHQd no cmuomaaoo Gamma“ Emum mmmnm whoocoo cmwuw m\noumum 0E cums .mln magma 150 HNm.H H mmoo. tho I ome H O u mammflu m\£oumum me o.m~ m.mm H.5m m.oo cchanu .OH + co .umumflaomma m.mn H.moa m.pm n.mm gunman» no: .oa + om .umumflaomma «.mm m.mm «.mm n.mv umcaflnu .oH + on .umumaaomoa m.mm m.~v m.mm m.m¢ nmnaflnu no: .OH + on .umumfiaomma m.hm ~.oh m.oma ~.>m cmccflnu .oa + om .umumflaommc uoz v.mm m.mm «.vm m.~m wchflnu uoa .OH + om .cmuMflHommc uoz H.mm m.mm m.~m m.vm commas» .oa + on .cmum«aommc uoz m.mm v.mm m.mm m.mm umccflnu no: .oH + om .cmumwaommc uoz @003 xumm maH>HA @003 xnmm mqw>wq mcwmwaamua Eouuom maflmwaamna moa usmfiummua u xnmm mcfl>wq .nuwm can Emamx u @003 .muwm Umcwmuvluwm mauoom .30H m Scum mnaa .ma kum< co vmuomaaoo mummfiu Emum mmmum wuoocoo vmwuc m\£oumum ma cum: .mla manna .EmoHnm can Edflnfimu A.uaoov umpomumc uoc u az . . mmpp. u Ham H Hmvmo. I omwooa mammwu m\noumum ma 151 92 az az oz umacflnu .OH + om .vmumflaomwa 92 oz az az cmccanu no: .0H + om .uwumaaommn ~.vm ~.HN m.mm m.wH cmcawnu .oa + on .vmuMHHome m.boa “.mm v.m~H h.ma wmcnwnu no: .oa + on .cmumwaommo m.nm m.mm ~.um N.>~ umacwnu .oa + co .vmumeOMmo uoz m.mm m.om m.mm «.mm wmcawnu #0: .oa + on .Umumfiaommv “oz o.m m.m v.a m.~ umamflnu .oa + om .cmuMHHommc uoz m.m a.» m.mH H.ma cmcaflnu no: .oa + on .umumflaommc uoz @003 xnmm mcw>flq U003 Mumm mcw>flq maflmflaamua eouuom mGHmHHHmHB moa usmfiummna maw>wq .zuwm cam Emamx u @003 .Ewoanm can Edflnawo thm .mufim wmcwmuwluwm Hamz .nmwz m Eonm tha .mH Hwnfimoma co vmuomaaoo Gamma» Emum mmmum whoocoo vmfluv m\£onmum.@8 cmmz .mIQ wanna 152 . mmop. u Hmm 1 "mafia. + ommooo momma» m\ooumum me oz oz oz .oz amazon» .oa + co .cmpmHHOMmo oz oz oz oz omooflnu poo .OH + om .nmuMHHommo >.mm m.m~ m.m¢ m.m¢ vmooflou .oH + om .vmumfiaommo «.mm m.~H m.ow m.~a amazon» poo .oH + om .wmumflaommo m.mm m.mm n.mm o.m~ vmoooop .oH + on .wmumaaommu uoz m.mm v.H~ m.moo v.m~ owooflou no: .oa + co .umuMflHOva uoz m.o o.m m.a m.a cocoon» .OH + om .wmumoaommo uoz o.m m.m m.mm H.m dmcownu poo .oa + om .UmuwHHOMmU #02 @003 xumm mafi>flq U003 Mumm mcw>fin mcfimwaawue Eouuom mcwmwaamua moa unwEummHa mca>wq .nnwm can Emahx n @003 .Emoanm can Edwnfimo u xumm .muwm umcwmnvluflm hauoom .30H m Baum meH A.ucoov .mH Hmnfimoma co wmuomaaoo 05mmwu Emum wmmum cuooooo vmwuv m\£oumum me now: .mIQ wanna 153 . Illlhhbbhllll u Hmm H _ho~o. I ammooo momma» m\£oumnm mE m.¢~ >.m~ H.ma H.m~ cmzoflnu .oH + om .0muMHH0mma H.om >.nm H.ma ¢.m~ 00ccwnu non .ca + om .0muMHH0mmo ~.vNH v.Hm n.mm .H.m¢ wwccfinu .oH + on .cmuMflaommn «.mHH 0.0m «.mm m.>m wmacflnu no: .oa + on .0000HH0m00 m.o~o H.0p m.moH o.mv umoooou .oo + om .omumoaoomo uoz m.maa o.mh N.wm H.m¢ nmoownu uoc .oH + co .00u0flH0m00 uoz m.wm >.mm m.om m.m~ 00ccwnu .oa + on .00umaa0mmn 002 I w.- m.oH H.Hm omccwau 00: .oa + om .00umaa0mmc 002 0003 xnmm mcw>flq 0003 xumm mGH>HA moomoaamue souuoo mcwmwaamna moa ucmfiummua u xumm mofi>flq .suflm cam Emamx n 0003 .Emoanm mow Edansmo .muwm cmnflmucIHHm HH03 .smws m Scum mnma .mH kum¢ no cmuomaaoo momma» Emum mmmum choocoo vmwnw m\noumum 08 com: .hlo mHQMB 154 bfloo. H Hmm._ H . I name ommao n 05mmwu m\soumum m8 m.m~ m.m~ m.mm m.mm wmooflou .oa + co .omuMoHommo 0.5m v.m~ m.m~ m.m~ cocoon» poo .oH + co .umuMoHoomo «.mmo «.mm m.vmo 0.5m umooflou .oo + om .nmumoaoomo v.vm m.mm n.0aa H.~m cmocflou no: .oa + on .nmumooommo m.mmo m.hm o.m¢H «.om amazon» .OH + om .omumooommw uoz c.5HH v.mv h.mma m.mm cocoon» poo .oa + om .umumoaommc uoz v.m¢ «.mm m.ma «.ma cmoofinu .oo + on .omuMflHommn uoz a.mm o.mm m.- m.mm amazon» no: .oa + on .cmumofloomo uoz 0003 xnmm mGH>HA 0003 xumm mcfl>aq unmaummua mcflmwaamna Eouuom mowmwaamua mos .Emoanm 0cm Edwnfimo u xnmm mnfi>flq .nuwm 0cm Emamx n 0003 .muwm vmcwmuvluwm mauoom .30H m Eoum mhma .mH kumm :0 vmyomaaoo 05mmwu Ewum mmmum whoonoo cmfluw m\noumum me now: 1.0couo .hlo GHAMB BIBLIOGRAPHY 10. 11. LITERATURE CITED (PREFACE) Alden, J. and R. K. Herman. 1971. Aspects of the cold-hardiness mechanism in plants. Bot. Rev. 37(1): 37-142. Clark, J. H. 1936. Injury to buds of grape varieties caused by low temperatures. Proc. Amer. Soc. Hort. Sci. 34: 408-413. Edgerton, L. J. 1960. Studies on cold hardiness of peach trees. Cornell Univ. Agr. Expt. Sta. Bul. 958. Fuchigami, L. H., D. R. Evert, and C. J. Weiser. 1971. A translocatable cold hardiness promoter. Plant Physiol. 47: 164-167. , C. J. Weiser, and D. R. Evert. 1971. Induction of cold acclimation in Cornus stolonifera Michx. Plant Physiol. 47: 98—103. Glerum, C., J. L. Farrar, and R. L. McLure. 1966. A frost hardiness study of six coniferous species. For Chron. 42(1): 69-75. Hamilton, D. E. 1973. Factors influencing dehardening and rehardening of Forsythia intermedia stems. J. Amer. Soc. Hort. Sci. 98(2): 221—223. Howell, G. S. 1969. The environmental control of cold hardiness in Haralson apple. Ph.D. thesis. Uni- versity of Minnesota, St. Paul. 64 pp. , and C. J. Weiser. 1968. What makes plants hardy? Horticulture 46: l9—20; 45. and . 1970. The environmental con- trol of cold acclimation in apple. Plant Physiol. 45: 390-394 and . 1970. Fluctuations in the cold resistance of apple twigs during spring dehardening. J. Amer. Soc. Hort. Sci. 95(2): 190-192. 155 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 156 Howell, G. S., and B. G. Stergios. 1975. Vine manage- ment effects on cold hardiness. Eastern Grape Grower. In press. Hurst, C., T. C. Hall, and C. J. Weiser. 1967. Reception of the light stimulus for cold acclimation in Cornus stolonifera Michx. HortScience 2(4): 164-166. Irving, M. R., and F. O. Lanphear. 1967. Dehardening and the dormant condition in Acer and Viburnum. Proc. Amer. Soc. Hort. Sci. 91: 699-705. and . 1967. Environmental control of cold hardiness in woody plants. Plant Physiol. 42: 1191-1196. and . 1967. The long day leaf as a source of cold hardiness inhibitors. Plant Physiol. 42: 1384—1388. and . 1968. Regulation of cold hardiness in Acer negundo. Plant Physiol. 43: 9—13. , Levitth. 1972. Responses of plants to environmental stresses. Academic Press, New York. 697 pp. Mazur, P. 1969. Freezing injury in plants. Ann. Rev. Plant Physiol. 20: 419-448. . 1967. Freezing stresses and survival. Ann. Rev. Plant Physiol. 18: 387—408. , B. L. Marchetti, and E. V. Chomyn. 1968. Ice structure in hardened winter barley. Mich. State Univ. Agr. Expt. Sta. Quarterly Bul. 50(4): 440-448. Parker, J. 1963. Cold resistance in woody plants. Pogosyan, K. S., and A. Sakai. 1969. Freezing resistance in grape vines. Hokkaido Univ., Low Temp. Sci. Ser. B: 125-144. , and M. M. Sarkisova. 1967. Frost resistance of grape varieties in relation to the condition of hardening. Soviet Plant Physiol. 14: 886-891. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. different climates. Ecology 51(2): 487-491. 157 Proebsting, E. L. 1963. The role of air temperatures and bud development in determining hardiness 0f dormant Elberta peach fruit buds. Proc. Amer. Soc. Hort. Sci. 83: 259-269. Roberts, D. W. A. 1971. The effect of CCC and Gibberellins A3 and A7 on the cold hardiness of Kharkov 22 MC winter wheat. Can. J. Bot. 49(5): 705-711. Sakai, A. 1966. Temperature fluctuations in wintering f“ trees. Physiol. Plantarum 19: 105-114. . 1970. Freezing resistance in willows from , and S. Yoshida. 1967. Survival of plant 3 tissue at super low temperature VI. Effects of ; cooling and rewarming rates on survival. Plant 3 Physiol. 42: 1695-1701. Shaulis, N. 1971. Vine hardiness a part of the problem of hardiness to cold in New York vineyards. Proc. New York State Hort. Soc. 116: 158-167. , J. Einset, and A. B. Pack. 1968. Growing cold tender grape varieties in New York. New York Agr. Expt. Sta. Bul. N0. 821. 16 pp. Steponkus, P. 1971. Cold acclimation of Hedera helix, evidence for a two phase process. Plant Physiol. 47: 175-180. , and F. O. Lanphear. 1967. Light stimulation of cold acclimation: production of a translocatable promoter. Plant Physiol. 42: 1673-1679. Stergios, B. G. 1975. Achene production, dispersal, seed germination and seedling establishment of Hieracium aurantiacum L. in an old field community. Can. J. Bot. In preparation. , and G. S. Howell. 1974. In situ destruction of dormant 'Concord' grape primary buds without secondary bud kill. HortScience 9(2): 120-122. and . 1975. Effects of defoliation, trellis height, and cropping stress on the cold hardiness of 'Concord' (Vitis labrusca L.) grape vines. Amer. J. Enol. Viticult. In preparation. 37. 38. 39. 40. 41. 42. 43. 158 Stergios, B. G., and G. S. Howell. 1975. Effects of defoliation and cropping stress on the size and pro- ductivity of 'Concord' (Vitis labrusca L.) grape vines. Amer. J. Enol. Viticul. In preparation. and . 1975. Effect of site on cold acclimation and deacclimation patterns in 'Concord' (Vitis labrusca L.) grape vines. Amer. J. Enol. Viticult. In preparation. Tumanov, I. I., and O. A. Krasavtsev. 1959. Hardening of northern woody plants by temperatures below zero. Soviet Plant Physiol. 6(6): 663-673. Van Hyustee, R. B., C. J. Weiser, and P. H. Li. 1967. Cold acclimation in Cornus Stolonifera Michx. under natural and controlled photoperiod and temperature. Bot. Gaz. 128: 200-205. Vasil'yev, I. M. 1956. Wintering of plants. Am. Inst. Biol. Sci., English trans. J. Levitt, ed. Washington, 1961. 300 pp. Weiser, C. J. 1970. Cold resistance and injury in woody plants. Science 169: 1269-1278. Wiggans, G. B. 1926. A study of the relative value of fruiting shoots arising from primary and secondary buds of the Concord grape. Proc. Amer. Soc. Hort. Sci. 23: 293-296. 10. ll. 159 LITERATURE CITED (SECTION ONE) Alden, J., and R. K. Hermann. 1971. Aspects of the cold-hardiness mechanism in plants. Bot. Rev. 37: 37-142. Darrow, G. M. 1966. The strawberry, history, breeding and physiology. Holt, Rinehart and Winston. 447 pp. Dexter, S. T., W. E. Tottingham, and L. F. Graber. 1930. Preliminary results in measuring the hardiness of plants. Plant Physiol. 5: 215-223. , and . 1932. Investigations ’ -————— of the hardiness of plants by measurement of electrical conductivity. Plant Physiol. 7: 63-78. Evert, D. R. and C. J. Weiser. 1971. Relationship of electrical conductance at two frequencies to cold injury and acclimation in Cornus stolonifera Michx. Plant Physiol. 47: 204-208. Fuchigami, L. H., C. J. Weiser, and D. R. Evert. 1970. Induction of cold acclimation in Cornus stolonifera Michx. Plant Physiol. 47: 98-103. Harris, R. E. 1970. Laboratory technique for assessing winter hardiness in strawberry (Fragaria x Ananassa Duch.) Can. J. Plant Sci. 50: 249-255. Howell, G. S., and C. J. Weiser. 1970. The environmen- tal control of cold acclimation in apple. Plant Physiol. 45: 390-394. and . 1970. Fluctuations in the cold resistance of apple twigs during spring dehardening. J. Amer. Soc. Hort. Sci. 95: 190-192. Hudson, M. A. and D. B. Idle. 1962. The formation of ice in plant tissues. Planta 57: 718-730. Levitt, J. 1971. Responses of plants to environmental stresses. T. T. Kozlowski, ed. Academic Press. 697 pp. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 160 Li, P. and C. J. Weiser. 1969. Increasing cold resistance of woody stems by artificial dehydration. Cryobiol. 6: 270. Loomis, G. P., R. A. Mecklenburg, and K. C. Sink. 1972. Factors influencing winter hardiness of flower buds and stems of evergreen azaleas. J. Amer. Soc. Hort. Sci. 97: 124-127. Luyet, B. J. and P. M. Gehenio. 1937. The double freezing point of living tissues. Biodynamica 30: 1-23. McLeester, R. C., C. J. Weiser and T. C. Hall. 1968. Multiple freezing points as a test for viability of plant stems in the determination of frost hardi- ness. Plant Physiol. 44: 37-44. , , and . 1968. Seasonal variations in freezing curves of stem sections of Cornus stolonifera Michx. Plant and Cell Physiol. 9: 807-817. Parker, J. 1953. Criteria of life: some methods of measuring viability. Amer. Sci. 41: 614-618. Steel, D. G. and J. H. Torrie. 1960. Principles and procedures of statistics. McGraw-Hill. p. 109-110. Steponkus, P. L., and F. O. Lanphear. 1967. Refinement of the triphenyl tetrazolium chloride method of determining cold injury. Plant Physiol. 42: 1423- 1426. , and . 1969. The relationship of anthocyanin content to cold hardiness of Hedera helix. HortScience. 4: 55-56. Weiser, C. J. 1970. Cold resistance and injury in woody plants. Science 169: 1269-1278. Wilner, J. 1959. Note on an electrolytic procedure for differentiating between frost injury of roots and shoots in woody plants. Can. J. Plant Sci. 39: 512-513. . 1960. Relative and absolute electrolytic conductance tests for frost hardiness of apple varieties. Can. J. Plant Sci. 40: 630-637. 10. 161 LITERATURE CITED (SECTION TWO) Alden, J. and R. K. Hermann. 1971. Aspects of the cold hardiness mechanism in plants. Bot. Rev. 37: 37-142. Bernsten, C. M. 1967. Relative low temperature tolerance of lodgepole and ponderosa pine seed- lings. Ph.D. Thesis. Oregon State University, Corvallis. 158 pp. Compana, R. 1964. Non-infectious tree diseases, Part 1. Effect of cold injury and freezing. Weed and Turf 3(8): 10-11, 22-23. Dethier, B. E. and N. Shaulis. 1964. Minimizing the hazard of cold in New York vineyards. New York Agr. Expt. Sta. Bul. N0. 1127. 7 pp. Duffy, P. J. B. and J. W. Fraser. 1963. Local frost occurrences in eastern Ontario woodlands. Can. Dept. Forestry Publ. 1029. 24 pp. Flint, H. L. 1972. Cold hardiness of twigs of Quercus rubra L. as a function of geographic origin. Ecology 53(6): 1163-1170. Haeseler, C. W. 1970. Climatic factors in the potential for wine grape production in several areas of Pennsylvania. Penn. State Univ. Agr. Expt. Sta. Prog. Report No. 303. 12 pp. Hamilton, D. F. 1973. Factors influencing hardening and rehardening of Forsythia intermedia stems. J. Amer. Soc. Hort. Sci. 98(2): 221-223. Howell, G. S. and C. J. Weiser. 1968. What makes plants hardy. Horticulture 46: 19-45. and . 1970. The environmental control of cold acclimation in apple. Plant Physiol. 45: 390-394. ll. 12. 13. 14. 15. 16. 17. l8. 19. 20. 21. 22. 162 Howell, G. S. and C. J. Weiser. 1970. Fluctuations in the cold resistance of apple twigs during Spring dehardening. J. Amer. Soc. Hort. Sci. 95(2): 190-192. Ketchie, D. O. and C. H. Beeman. 1973. Cold accli- mation in 'Red Delicious' apple trees under natural conditions during four winters. J. Amer. Soc. Hort. Sci. 98(3): 257-261. Lorenzetti, F., B. F. Tyler, J. P. Cooper, and E. L. Breeze. 1971. Cold tolerance and winter hardiness in Lolium perenne. l. Deve10pment of screening techniques for cold tolerance and survey of geo- graphical variation. J. Agri. Sci., 76: 199-209. Michigan Climatological Data. A U.S. Dept. of Commerce Pub. 86(2-5). Feb.-May, 1971; 86(9). Sept., 1971. Parker, J. 1963. Cold resistance in woody plants. Bot. Rev. 29(2): 123-201. Partridge, N. L. 1925. The fruiting habits and pruning of the Concord grape. Mich. State Agr. Expt. Sta. Bul. N0. 69. 39 pp. Pogosyan, R. S. and A. Sakai. 1969. Freezing resis- tance in grape vines. Hokkaido Univ., Low Temp. Sci. Ser. B. 27: 125-144. Proebsting, E. L. 1963. The role of air temperatures and bud development in determining hardiness of dormant Elberta peach fruit buds. Proc. Amer. Soc. Hort. Sci. 83: 259-269. and H. H. Mills. 1961. Loss of hardiness by peach fruit buds as related to their morphologi- cal development during the pre-bloom and bloom period. Proc. Amer. Soc. Hort. Sci. 78: 104-110. Sakai, A. 1970. Freezing resistance in willows from different climates. Ecology 51(2): 487-491. Shaulis, N. 1970. New York site selection for wine grapes. Proc. New York State Hort. Soc. 115: 288-294. . 1971. Vine hardiness a part of the problem of hardiness to cold in New York vineyards. Proc. New York State Hort. Soc. 116: 158-167. 23. 24. 25. 26. 27. 28. 29. 163 Shaulis, N., J. Einset, and A. B. Pack. 1968. Growing cold-tender grape varieties in New York. New York Agri. Expt. Sta. Bul. N0. 821. 16 pp. Smithberg, M. H. and C. J. Weiser. 1968. Patterns of variation among climatic races of red-osier dogwood. Ecology 49(3): 495-505. Stergios, B. G. and G. S. Howell. 1972. Evaluation of viability tests for cold stressed plants. J. Amer. Soc. Hort. Sci. 98(4): 325-330. and . 1974. In situ destruction of dormant Concord grape primary buds without secondary bud kill. HortScience 9(2): 120-122. Van Hyustee, R. B., C. J. Weiser and P. J. Li. 1967. Cold acclimation in Cornus stolonifera and natural and controlled phot0peri0d and temperature. Bot. Gaz. 128: 200-205. Weiser, C. J. 1970. Cold resistance and injury in woody plants. Science 169: 1269-1278. Wildermuth, R., J. A. Kerr, F. W. Trull, J. W. Stack. 1926. Soil survey of Van Buren Co., Michigan. U.S. Dept. of Agriculture, Bureau of Soils. 42 pp. 10. 164 LITERATURE CITED (SECTION THREE) Banta, E. S., G. A. Cahoon and R. G. Hill. 1970. Grape growing. Ohio State Univ. Coop. Ext. Ser. Bul. No. 509. 24 pp. Clark, J. H. 1936. Injury to buds of grape varieties caused by low temperatures. Proc. Amer. Soc. Hort Sci. 34: 408-413. Clore, W. J., M. A. Wallace, and R. D. Fay. 1974. Bud survival of grape varieties at sub-zero temperatures in Washington. Amer. J. Enol. Viticult. 25(1): 24-29. Dethier, B. E. and N. Shaulis. 1964. Minimizing the hazard of cold in New York vineyards. New York Agr. Expt. Sta. Bul. No. 1127. 7 pp. Edgerton, L. J. and N. J. Shaulis. 1953. The effect of time of pruning on cold hardiness of Concord grape canes. Proc. Amer. Soc. Hort. Sci. 63: 209- 213. Folwell, R. J. 1973. The market situation and outlook for Concord grapes 1973. Washington State Grape Society Proc., 1973. 11 pp. Fuchigami, L. H., C. J. Weiser, and D. R. Evert. 1971. Induction of cold acclimation in Cornus stolonifera Michx. Plant Physiol. 47: 98-103. , and D. G. Richardson. 1973. The influence of sugars on growth and cold accli- mation of excised stems of Red- -osier dogwood. J. Amer. Soc. Hort. Sci. 98(5): 444-447. Haeseler, C. W. 1970. Climatic factors in the potential for wine grape production in several areas of Pennsylvania. Penn. State University Agr. Expt. Sta. Prog. Report. No. 303. Howell, G. S., and C. J. Weiser. 1970. Fluctuations in the cold resistance of apple twigs during spring dehardening. J. Amer. Soc. Hort. Sci. 95(2): 190-192. ll. 12. l3. 14. 15. 16. 17. 18. 19. 20. 21. 165 Howell, G. S., and C. J. Weiser. 1970. The environ- mental control of cold acclimation in apple. Plant Physiol. 45: 390-394. and S. S. Stackhouse. 1973. The effect of defoliation time on acclimation and dehardening in tart cherry (Prunus cerasus L.). J. Amer. Soc. Hort. Sci. 98(2T?5132-136. Hurst, C., T. C. Hall, and C. J. Weiser. 1967. Reception of the light stimulus for cold accli- mation in Cornus stolonifera Michx. HortScience 2(4): 164-166. Irving, M. R. and F. O. Lanphear. 1967. The long day leaf as a source of cold hardiness inhibitors. Plant Physiol. 42: 1384-1388. Khudairi, A. K. and R. C. Hamals. 1954. The relative sensitivity of Xanthium leaves of different ages to photoperiodic induction. Plant Physiol. 29: 251-257. Kliewer, W. M., L. A. Lider, and N. Ferrari. 1972. Effects of controlled temperature and light intensity on growth and carbohydrate levels of Thompson Seedless grapevines. J. Amer. Soc. Hort. Sci. 97(2): 185-188. Larsen, R. P., H. K. Bell, and J. Mandigo. 1957. Pruning grapes in Michigan. Mich. State Univ.‘ Ext. Bul. No. 347. 16 pp. May, P., N. J. Shaulis, and A. J. Antcliff. 1969. The effect of controlled defoliation in the Sul- tana vine. Amer. J. Enol. Viticult. 20(4): 237- 250. Michigan Dept. of Agriculture. Michigan Agricultural Statistics. June, 1974. p. 24. New York State Dept. of Agriculture and Markets, Bureau of Statistics; New York Crop Renting Service. New York Orchard and Vineyard Survey -- 1970. AMA Release No. 125. July, 1971. pp. 30-34. New York Dept. of Agriculture and Markets, Bureau of Statistics; New York Crop Reporting Service. Fruit Report. January 1, 1974. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 166 Olien, C. R. 1967. Freezing stresses and survival. Ann. Rev. Plant Physiol. 18: 387-408. Partridge, N. L. 1925. Profitable pruning of the Concord grape. Mich. Agr. College Agr. Expt. Sta. Special Bul. N0. 141. 12 pp. . 1925. The fruiting habits and pruning of the Concord grape. Mich. State Agr. Expt. Sta. Tech. Bul. N0. 69. 39 pp. . 1931. The influence of long pruning and thinning upon the quality of Concord grapes. Proc. Amer. Soc. Hort. Sci. 28: 144-146. , and A. Sakai. 1969. Freezing resistance in grape vines. Hokkaido Univ., Low Temp. Sci. Ser. B 27: 125-144. Pogosyan, K. S., and M. M. Sarkisova. 1967. Frost resistance of grape varieties in relation to the condition of hardening. Soviet Plant Physiol. 14: 886-891. Potter, G. F. 1938. Low Temperature effects on woody plants. Proc. Amer. Soc. Hort. Sci. 36: 185-195. Proebsting, E. L. 1963. The role of air temperature and bud deve10pment in determining hardiness of dormant 'Elberta' peach buds. Proc. Amer. Soc. Hort. Sci. 83: 259-269. , and H. H. Mills. 1961. Loss of hardiness by peach fruit buds as related to their morpho- logical deve10pment during the pre-bloom and bloom period. Proc. Amer. Soc. Hort. Sci. 78: 104-110. , and . 1972. A comparison of hardiness responses in fruit buds of 'Bing' cherry and 'Elberta' peach. J. Amer. Soc. Hort. Sci. 97(6): 802-806. Sakai, A. 1966. Temperature fluctuation in wintering trees. Physiol. Plantarum 19: 105-114. . 1966. Studies of frost hardiness in woody plants. II. Effect of temperature on hardening. Plant Physiol. 41: 353-359. Shaulis, N. 1970. New York site selection for wine grapes. Proc. New York State Hort. Soc. 115: 288-294. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 167 Shaulis, N. 1971. Vine hardiness a part of the problem of hardiness to cold in New York vineyards. Proc. New York State Hort. Soc. 116: 158-167. , H. Amberg, and D. Crowe. 1966. Response of Concord grapes to light, exposure and Geneva Double Curtain training Proc. Amer. Soc. Hort. Sci. 89: 268-280. , J. Einset, and A. B. Pack. 1968. Growing cold—tender grape varieties in New York. New York Agr. Expt. Sta. Bul. No. 821. Smart, R. E. 1973. Sunlight interception by vineyards. Amer. J. Enol. Viticul. 24(4): 141-147. Steponkus, P. L., and F. O. Lanphear. 1966. The role of light in cold acclimation. Proc. XVII Inter- national Hort. Congress. 1: 93. , and . 1967. Light stimulation of cold acclimation: Production of a translocatable promoter. Plant Physiol. 42(12): 1673-1679. , and . 1968. The relationship of carbohydrates to cold acclimation of Hedera helix L. cv. Thorndale. Physiol. Plant 21: 777-791. Stergios, B. G., and G. S. Howell. 1972. Evaluation of viability tests for cold stressed plants. J. Amer. Soc. Hort. Sci. 98(4): 325-330. , and . 1974. In situ destruction of dormant 'Concord' grape primary buds without second- ary bud kill. HortScience 9: 120-122. , and . 1975. Effect of site on cold * 0 fl 0 I O acclimation and deacclimation patterns in Concord grape (Vitis labrusca L.) vines. Amer. J. Enol. Viticult. In preparation. , and . 1975. Effects of defoliation and cr0pping stress on the size and productivity of 'Concord' grape (Vitis labrusca L) vines. Amer. J. Enol. Viticult. In preparatIon. Tomkins, J., and N. Shaulis. 1957. The Catawba grape in New York. II. Some effects of severity of prun- ing on the production of fruit and wood. Proc. Amer. Soc. Hort. Sci. 66: 214—219. 168 47. Wildermuth, R., J. A. Kerr, F. W. Trull, and J. W. Stack. 1926. Soil survey 0f Van Buren Co., Michigan. U.S. Dept. of Agriculture, Bureau of Soils. 42 pp. 48. Winkler, A. J. 1970. General viticulture. Univ. Calif. Press. Berkeley, Los Angeles, London. 633 pp. 10. 169 LITERATURE CITED (SECTION FOUR) Bradt, O. A. 1967. Effect of pruning severity and bunch thinning on yield and vigor of Buffalo and Catawba grapes. Report of the Horticultural Research Institute of Ontario. pp. 22-27. Clore, W. J. and V. P. Brummund. 1969. The effect of vine size on the production of Concord grapes balance pruned. Proc. Amer. Soc. Hort. Sci. 78: 239-244. Hamilton, J. 1953. The effect of cluster thinning on maturity and yield of grapes 0n the Yuma Mesa. Proc. Amer. Soc. Hort. Sci. 62: 231-234. Harris, J. M., P. E. Kriedemann, and J. V. Possingham. 1968. Anatomical aSpects of grape berry develop- ment. Vitis 7: 106- 119. Kimball, K. and N. Shaulis. 1958. Pruning effects on the growth, yield, and maturity of Concord grapes. Proc. Amer. Soc. Hort. Sci. 71: 167-176. Larsen, R. P. and H. K. Bell, and J. Mandigo. 1972. Pruning grapes in Michigan. Mich. State Univ. Ext. Bul. No. 347. 16 pp. Maney, T. J. and H. H. Plagge. 1935. A study of production and physiology of Concord grape vines as affected by variations in the severity of pruning. Proc. Amer. Soc. Hort. Sci. 32: 392-396. May, P. and A. J. Antcliff. 1963. The effect of shading 0n fruitfulness and yield in the sultana. J. Hort. Sci. 38: 85-94. , N. J. Shaulis, and A. J. Antcliff. 1969. The effect of controlled defoliation in the Sultana vine. Amer. J. Enol. Viticul. 20(4): 237-250. Partridge, N. L. 1925. The fruiting habits and pruning of the Concord grape. Mich. State College Agri. Expt. Sta. Tech. Bul. N0. 69. 39 pp. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 170 Partridge, N. L. 1931. The influence of long pruning and thinning upon the quality of Concord grapes. Proc. Amer. Soc. Hort. Sci. 28: 144-146. Ragland, C. H. 1940. A preliminary report on the effect of cluster thinning on the maturity, yield, and cluster size of grapes. Proc. Amer. Soc. Hort. Sci. 37: 661-662. Sharples, G. C., R. H. Hilgeman, and R. L. Milne. 1957. The relation of cluster thinning and trunk girdling of Cardinal grapes to yield and quality of fruit in Arizona. Proc. Amer. Soc. Hort. Sci. 66: 225-233. Shaulis, N., H. Amberg, and D. Crowe. 1966. Response of Concord grapes to light, exposure and Geneva double curtain training. Proc. Amer. Soc. Hort. Sci. 89: 268-280. and P. May. 1971. Response of 'Sultana' vines to training on a divided canopy and to shoot crowding. Amer. J. Enol. Viticult. 22(4): 215-222. and G. D. Oberle. 1948. Some effects of pruning severity and training on Fredonia and Concord grapes. Proc. Amer. Soc. Hort. Sci. 51: 263-270. and G. D. Steel. 1969. The interaction of resistant rootstock t0 the nitrogen, weed control, pruning and thinning effects on the productivity of Concord grapevines. J. Amer. Soc. Hort. Sci. 94: 422-429. Steel, G. D. and J. H. Torrie. 1960. Principles and procedures in statistics. McGraw-Hill, New York. 481 pp. Stergios, B. G. and G. S. Howell. 1975. Effect of site on cold acclimation and deacclimation patterns in 'Concord' (Vitis labrusca L.) grape vines. Amer. J. Enol. Viticult. In preparation. and . 1975. Effects of defoliation, trellis height, and cropping stress on the cold hardiness of 'Concord' (Vitis labrusca L.) grape vines. Amer. J. Enol. Viticult. In preparation. 171 21. Tomkins, J. and N. Shaulis. 1957. The Catawba grape in New York II. Some effects of severity of prun- ing on the production of fruit and wood. Proc. Amer. Soc. Hort. Sci. 66: 214-219. 22. Wildermuth, R., J. A. Kerr, F. W. Trull, and J. W. Stack. 1926. Soil Survey of Van Buren Co., Michigan. U.S. Dept. of Agriculture, Bureau of Soils. 172 LITERATURE CITED (SECTION FIVE) Clark, J. H. 1936. Injury to the buds of grape varieties caused by low temperatures. Proc. Amer. Soc. Hort. Sci. 34: 408-413. Pogosyan, R. S. and M. M. Sarkisova. 1967. Frost resistance of grape varieties in relation to the conditions of hardening. Soviet Plant Physiol. 14: 886-891. Pratt, Charlotte. 1959. Radiation damage in shoot apices of Concord grape. Amer. J. Bot. 46: 103- 109 O Sakai, A. 1969. Freezing resistance in grape vines. Low Temp. Sci. Ser. B. 27: 125-144. Stergios, B. G. and G. S. Howell. 1973. Evaluation of viability tests for cold stressed plants. J. Amer. Soc. Hort. Sci. 98: 325-330. Wiggans, G. B. 1926. A study of the relative value of fruiting shoots arising from primary and secondary buds of the Concord grape. Proc. Amer. Soc. Hort. Sci. 23: 293-296. ~ I. .009 I... 'cI). nicuxcn N 23112 9 ST TE UNIV. LIBRARIES "WIWI'IWWIWINWHIWIW“WI 93007091949