I 1 AN A AAA HTIA RELATTONSHTP OF LEAF AREA TO TOTAL WEIGHT AND AVERAGE WETGHT OF FRUT ?N BLUEBERRTES THESIS FUR THE DEGREE OF M. 3. Duncan A. Byrd 1930 A_ A: fin fr. flap-M ‘ 3 1293 JWMMMI II I WT Relationship of Leaf Area to Total Weight and Average Weight of Fruit in Blueberries. Thesis Presented to the faculty of the Michigan State College of Agriculture and Applied Sci- .ence as partial fulfillment of the requirements for the D degree of \q3 master of Science / m 01/ by K» [/ ,._,.,,-: Duncan A. Byrd. ,/ 1950‘ w ‘~») INTRODUCTIOH Realization of the full importance of leaves to fruit bearing plants has come but slowly. Since earliest times gardeners and botanists have been aware that plants draw moisture and nutrients from the soil. Transpiration was recognized as a leaf function comparatively early, but understanding of other functions of the leaves almost entirely depended on the development of fin chemistry of the air and of the plants. Even when the intake of carbon was demonstrated by plant physiologists, gardeners were slow to recognize the significance of the leaves and, with few exceptions, pruning was still practised on the basic conception of economising on nutrients taken from the soil. Defoliation, as occasioned by fungi and insects, was recognized as injurious, but up to the appearance of ‘the work by Irene and Kraybilflnbn the relationship of nitrogen and carbohydrates to fruitfulness, the significance of leaves was regarded lightly by horticulturists in general. It is generally known that the leaf area of.a plant bears a certain relation to the degree a plant is fruitful. Pruning trees, bushes, and thinning of fruit has been practised for years, but it was not until recently that data were presented to show that a certain definite 94288 leaf area is necessary in order to allow for the preper development of a given quantity of fruit. By thinning of fruit, gardeners and horticulturists know that the size and quality of the fruit is improved. However, Just what ratio should exist between the leaf area and the number fruits has not been known. Without this ratio.in mind the grower cannot thin fruit to the best commercial advantage. Neither was it known, until recently, to what extent the fruit is dependent upon the closely adjoining leaf area, or whether for its development it may draw upon foods which are elaborated at considerable distances. Definite information about these matters is fundamental to studies of growth and chemical compositions of fruit, and the general productivity of a plant. '- REVIEW OF LITERATURE - In 1924 Heller and Magness started certain experiments in order to throw some light on these problems. During 1924 these workers used Winesap, Ben Davis, Delicious, and Rome Beauty varieties. Twigs were ringed to prevent translocation of food materials. The results in 1924 were variable but clearly indicated a relationship between the leaf area and size of fruit. During 1925, the varieties used were Delicious, Ben Davis, and Grimes. The leaf area was increased for each fruit. The results of this work show there was a marked correlation between the leaf area and the increase in volume of fruit, up to a certain point, beyond which a further increase in the leaf area did not result in a corresponding increase in volume. For the Grimes and Ben Davis it was found that thirty to forty medium sized leaves per fruit were necessary to obtain apples of good size and quality. Data gathered in these experiments seem to indicate that apples are able to draw upon leaves which are as much as one hundred centimeters away, and upon leaves which are adjacent to the fruit with almost equal facility. A high percentage of dry weight,sugars and acids, is associated with apples grown with large leaf area as compared with apples 6f the same variety grown with small leaf area?/ In 1926 Magness conducted an experiment in the state of Washington similar to the earlier work in Virginia, working with Delicious, Winesap, and Jonathan varieties. Detailed tests were made on the DeliciOus with limited observations on Winesap and Jonathan. The procedure was similar to the work previously carried on in Virginia. Magness states that unless forty to fifty leaves per fruit are available on Delicious, best market sizes and quality fruit cannot be produced. However, the total efficiency of the foliage at Wenatchee, Washington, seemed to be greater. This is accounted for by the more intense and continuous sunshine, and the greater daily insolation.3 Johnston of the South Haven Experiment Station, South Haven, Michigan, in the work on the winter pruning of black raspberries found that the highest total yields of berries were found-on the shoots with the most foliage and likewise the average weight per berry was . 4 proportionatelly larger. - Object of Experiment — As has been shown in the review of literatuge, there has been little work carried on to show just what relationship exists between the leaf area and fruitfulness. These investigations were restricted to the apple and- raspberry. The purpose of this investigation was to study the relationship between the leaf area and the total weight and average weight of fruit of the blueberry plant on selected individual shoots. Very little work has been done in respect to pruning of the blueberry bush and a knowledge of this relationship is fundamental in order to prune intelligently. - Materials and Methods — This work was started July lst, 1929. The plants used in connection with this experiment were growing on one of the experimental plots at the South Haven experiment station, bouth Haven, Michigan. These plants were growing in a Saugatuck loamy fine sand, and the soil apparently was uniform and possessed the requirements for good blueberry growth. Seven varieties were used in gathering the data presented in this paper. _flag§__ NO. Shoots. Adams 28 Early Varieties . Cabot 24 Katherine 58 Midseason Varieties Pioneer 28 Sam 27 hubel 45 Late Varieties Harding 27 The plants selected were average plants growing on the plot. Shoots were selected from different portions of the plant and were tagged with a paper tag bearing a number. A cage constructed of mosquito netting was placed about each selected bush, this serving to prevent destruction of the berries by outside agencies. The berries were harvested once a week after 'ripening had commenced and were picked only on dry days. After all data had been assembled the coefficient of correlation was worked out for each variety. Figure #1. A portion of the blueberry plants used in the investigation. Records Taken The following records were taken: 1. Total weight of the berries, at each picking. 2. Total number of berries. 5. Leaf area on shoot upon which the berries were borne. The berries were weighed upon balance scales which registered in sixteenths of ounces. After all the berries were harvested from the tagged shoots the leaves were collected and measured by the use of a planimeter. The data collected is recorded in tables one to seven inclusive. — ADAES VAhlhTY - Comparison of leaf areas, total weights and average weights of fruit. Shoot No. No. Berries Total Average Leaf Area height height in Sq. Inches. (wt. in ounces) 1 25 '71 .050 20.70 2 45 1.40 ' .052 54.09 5 40 1.56 .054 27.66 4 50 . 1.09 .056 19.84 5 20 .80 .080 15.88 6 56 1.56 .057 11.11 7 19 .62 .057 7.45 8 16 .68 .042 11.99 9 28 1.09 .042 52.65 10 22 .79 .035 50.89 11 8 .24 .050 14.50 12 . 12 .54 .028 5.02 15 11 .58 .004 2J.82 14 15 .54 .058 12.66 15 10 .54 .054 A 10.05 16 11 .42 .058 11.69 17 a .50 .027 22.59 18 27 1.09 .045 2-79 19 21 .72 _ .054 25.12 20 11 .42 .058 15.74 21 15 .42 .052 3.09 Table 1 page 2 Twig No. 22 25 24 25 26 27 28 No. Berries Total Average Leaf Area height Keight in Sq. Inches 10 .20 .020 15.98 21 .68 .052 24.15 25 .85 .056 14.28 7 .26 .057 20.58 15 .44 .029 16.81 15 .55 .040 7.27 12 .40 .055 6.57 The coefficient of correlation for this variety is found to be as follows: I G? u ‘i + Total weight r _ Avirage weight r = J/¢ + Shoot 10 11 12 15 14 15 16 17 18 19 2O 21 22 Comparison of leaf areas, total heights and No. — CABOT VARIETY - Table #2 average weights of fruit. (weight in ounces) Berries 27 2O 15 17 18 15 46 26 24 58 57 Total Weight .91 .72 .62 .46 1.42 .78 .71 Average height .054 .056 .041 .041 Leaf in Sq. 52.72 11.62 15.20 10.1J 15.57 20.96 Area Inches Table #2 Page 2 Shoot No. No. Berries Total Average height Leignt 25 24 .78 .052 24 28 .86 .050 25 25 .92 .040 Total height I‘ Z .574 I .118 Aver ge height r : -.011 ; .204 Shoot No. 10 ll l2 l5 14 15 16 17 18 19 20 Comparison of leaf areas, total weights and No. Table #5 - KATi-l‘hli-TE VAT-ILTY - average weights of fruit. (weight in ounces) Berries ll 18 24 17 17 14 15 10 21 55 Total Weight .68 .50 .22 .42 .54 .94 .55 .50 .56 .78 Average Target .040 .057 .05 .058 .05 .059 .041 .058 .057 .057 .040 u .7‘ I'L.) f. " U‘t‘vé in 8:. 16.18 25.18 54.59 A l" e a Inches Table 5 Page 2 _ 8413181“; VnhlnTY — Shoot No. No. Berries Tot;1 Averag Leaf Lrea height Leight in to. Inches 21 81, 1.12 .088 8.42 22 12 .84 .048 11.60 25 26 1.09 .042 1.88 24 18 .84 .048 12.08 28 17 .88 .052 8-66 28 28 1.08 .040 19-35 27 18 .84 .0~8 2-92 28 48 1.46 .081 ~82 29 18 .48 .080 1-89 50 18 .52 .024 3-47 81 20 .71 .088 4.55 52 82 .84 .026 4.16 88 19 .55 .027 .84 54 15 .54 .088 11.89 55 48 1.84 .088 9.87 56 14 .42 .080 14.25 57 26 1.18 .044 10-54 58 2 .08 .08 15-72 39 89 1.55 .049 25-55 Table 5 Pc’i 14:8 5 Shoot 41 — KfiTfighlnE VA ILTY . Log; F v..- in 50. 9.07 17.98 6.01 10.65 14.54 12.58 (.59.) irca Inches — PION:LE VAhlaTY - T371e #4 Comparison of leaf areas, Shoot No. 10 11 15 14 15 16 17 18 19 20 21 ave:age weights No. Berries Total total height .24 .92 of fruit. V. 6 1 d L” and Table #4 Page 4 Shoot ho. ho. Berries Total Average Leaf Area height weight in Lq. Inches 22 45 1.07 .025 5.24 25 55 1.55 .027 16.91 24 61 1.91 .051 20.59 25 40 1.28 .055 9.50 26 61 1.86 .050 15.96 27 54 1.15 .050 17.05 28 24 .78 .052 4.14 Total Leight r : .88 I .028 Ave.age height r z -.025 7 .186 Table #5 - SAM VARIbTY — Comparison of leaf areas, Shoot No. 10 11 12 15 14 15 17 18 19 m C) No. weights Berries 56 45 59 45 22 4O 57 19 Of fI‘Uit. Total .92 .46 .09 Average height .029 total weights and average 44.47 21.24 26.15 50.55 11.17 21.12 Leaf Area in bq. Inches Table 5 Page 2 Shoot No. 21 22 25 24 25 26 27 "’ SAM VARIETY "’ No. Berries 40 29 12 15 50 52 Total Average Weight Weight .86 .021 .48 .015 .50 .025 .44 .029 1.15 .025 .18 .025 .60 .018 Total Weight I 3 Average Weight r I .253 .390 ; Leaf Area in Sq. Inches 45.99 20.02 12.81 5.41 8.47 3.26 19.26 .079 4. 0004 Table #6 — RUBEL VARIETY — Comparison of leaf areas, total weights and average weights of fruit. Shoot 50. No. Berries Sotal Average Leaf A ea height height in fig. Inches 1 7 -l4 .020 2.52 2 21 -25 .012 11.92 5 8 -l8 .022 15.17 4 8 -24 .050 44.49 5 27 -59 .021 10.54 6 55 -65 .019 9.79 7 11 .46 .041 5.75 8 1° .55 .055 15.78 9 28 .62 .056 15.51 10 15 ~24 .018 7.08 11 56 1.09 .050 .76 12 19 .52 .027 2.09 15 46 1.42 .050 55.47 14 14 .52 .022 25.40 15 8 .24 .050 5.87 16 9 .28 .051 4.76 17 5 .12 .024 2.47 .18 18 .40 .022 16.70 219 5 .09 .018 9.11 2C) 26 .84 .052 15.40 Table 6 Page 2 Shoot No. 21 22 25 24 55 54 55 56 57 58 4O ‘41 ‘42 ‘45 Ne. 12 9 22 18 15 - RUBEL VARIETY - Berries Total height .55 .29 .48 .27 .15 .62 .54 .65 .96 .59 .70 Average Reight .027 28.47 8.05 8.95 58.24 Leaf Axea in Sq. Inches Table 6 Page 5 Shoot No. 44 45 - hUBEL VALILTY No. Berries Total Ave age Leaf Area height Leight in Sq. Inches 17 .62 .355 1.05 51 .95 .050 Total height r - .189 Average height r Shoot Ho. 10 11 12 14 15 16 17 18 Comparison of leaf areas, NO I 28 49 24 27 27 55 18 49 15 21 40 16 average weights Berries Table 27 TV. . nah IhG VARIETY - Total Leight total .. . -.1 heignt‘ Of frujto Average height .059 .026 .024 .051 .024 Leaf in bq. 45.05 12.70 16.96 14.55 7.91 25.28 8.41 57.10 25.97 2.88 Area Inches Table 7 page 2 — HABDING VARIETY - Shoot No. No. Berries Total height Average Leaf Area Height in be. Inahes 19 58 1.09 .028 25.92 20 14 .40 .028 21.65 21 16 .46 .028 65.41 22 51 .84 .027 7.07 25 14 .24 .017 9.15 24 10 .26 .026 41.28 25 40 1.06 .026 58.28 26 26 .82 .051 7.81 27 7 .15 .021 10.15 28 28 .74 .026 10.25 Total Leight r 3 -.152 .; .188 Average height r = .729 J; .060 —--— Table #8 Summary of the Coefficient of Correlation for the varieties used. Correlation .__ —._-- - Variety Total Reighi“ Average height Adams .579 r .108 .114 5‘.125 Cabot .574 ; .118 -.011 : .204 Katherine .129 I .086 .050 1 .088 Pioneer .88 ; .028 -.025 1 .186 Sam .590 1 .079 —.255 :_.004 hubel .189 1 .007 .429 a .102 Harding —.152 —+ .188 .729 I .060 except - RESULTS - No positive correlations were found in this work in the following two cases: For the Pioneer Variety, the correlation was .88.? .028 for the total weight. For the Harding Variety, the correlation was .72 $’.060 for the average weight. Negative correlations were found in the following Harding - .15 ET.188 for total weight Cabot — .011 ¥-.204 for average weight Pioneer 4 .025 ¥ .186 for average weight Sam - .255 5 .004 for average weight Discussion and Canclusions The data presented plainly shows that the relation— ship between the leaf area and the total weight and the average weight of the fruit on a given shoot is small. The results show that there are great variations in the weights and leaf areas. Certain shoots bore a very small leaf area and produced a large total weight and average weight of the fruit. Other cases are seen where a large leaf area is accompanied by a small total weight and average weight of fruit. The bushes used in connection with this investigation had been pruned quite heavily for several years in an effort to secure a supply of propagating stock. This may have upset some of the metabolic functions of the plant to some degree. It is also believed that the berries of a particular shoot are not dependent on the adjacent leaf area for elaborated food, but it may rely on more distant leaves as a source of elaborated food. The explanation for the increase in total weight and average weight of the fruit of one shoot over that of another is not exphflnable by the increase or decrease of leaf area. The cause is evidently due to other factors. Acknowledgments The writer is greatly indebted to Professor V. R. Gardner, Professor F. 0. Bradford and nr. Stanley Jehnston for their assistance throughout the work, from the original planning of the experiment to the completion of the manuscript. 1. 2. 5. 4. - BIBLIOGRAPHY - Kraus, E. J., and Kraybill, H. R. ~"Vegetation and Reproduction with Special Reference to the Tomato” - Oregon Agricultural Experiment Station Bulletin, No. 149 - 1918. M. H. Haller and J. R. Magness - "Relation of Leaf Area to the Growth and Composition of Apples" ~ Report of American Society for Horti- cultural Science 1925. mangoes, J. R. ~ "Relation of Leaf Area to Size and Quality in the Apple" - Report of American Society for Horticultural Science 1928. Johnson, Stanley - "Winter Pruning of Black Raspberry" -Michigan Agricultural EXperiment Station Special Bulletin, No. 145 - 1925. .2752; ROOM USE (MY Feb 24’“ H... 151.... 2.. i122 . ‘ lint . €4,214): "1.1111111111474414“