M HillflmlllmflllllllVl‘lWll LIBRARY 31293 01097 2762 Michigan State University This is to certify that the thesis entitled EFFECT OF CHLORFLURENOL AND NITROGEN FERTILIZATION ON PICKLING CUCUT’IBER presented by Soenoeadji has been accepted towards fulfillment of the requirements for M. S . degree in Horticulture 12w 0 )La.‘ Major professor Robert C. Herner Datei? OCA- ”77' 0.7639 V9,; 9 V my 5- I 74 " :Q' “I a (\A‘ 4 1.;- o .- 1- 3’ 3" '7 if r I I1 1‘ .I'r‘, til Fltii‘ll'll.‘ ill \u’l‘lvi'r‘l-ll ‘v till \«i. ‘2 1 o l EFFECT OF CHLORFLURENOL AND NITROGEN FERTILIZATION 0N PICKLING CUCUMBER By Soenoeadji A THESIS Submitted to MICHIGAN STATE UNIVERSITY in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE Department of Horticulture 1977 ABSTRACT EFFECT OF CHLORFLURENOL AND NITROGEN FERTILIZATION ON PICKLING CUCUMBER By Soenoeadji “Premier" pickling cucumbers were grown at l20,000 plants/ha on Conover loam soil in l975. Chlorflurenol at 250 ppm was applied when 5, 7, or 9 female flowers reached anthesis. Nitrogen was applied at 28 and ll2 kg/ha. Yield increase (kg/ha and $/ha) was greatest when chlorflurenol was applied early in plant development (5 flower stage). Increased yield was attributable to increased fruit number in the smaller and more valuable size grades with chlorflurenol. Undesirable effects of chlorflurenol were an increase in the number of misshapen fruits and a reduction in the length-diameter ratio. Length-diameter ratio reduction was greater with earlier application of chlorflurenol. Nitrogen rate had no significant effect on yield or frutt shape and did not reduce the undesirable effects of chlorflurenol. ACKNOWLEDGEMENT I would like to express my sincere appreciation to Drs. James E. Motes, Hugh C. Price, and Robert C. Herner for their help and assistance as this work was being conducted, and for their review and suggestions in the preparation of the manuscript. I am also very grateful to Drs. Darryl D. Warncke and Bill Dean for their service on my Guidance Committee. I wish to express special thanks to those members of the Department of Horticulture who made their laboratory facilities available for my work. ii TABLE OF CONTENTS 333g ACKNOWLEDGEMENTS ........................ ii TABLE OF CONTENTS .- ...................... iii LIST OF TABLES . . . . ..................... iv LIST OF FIGURES ......................... vi INTRODUCTION ......................... l LITERATURE REVIEN ........................ 3 MATERIAL AND METHODS ...................... 8 RESULTS ............................ l0 DISCUSSION ........................... 34 SUMMARY AND CONCLUSIONS ..................... 45 LITERATURE CITED ........................ 47 iii Table Table Table Table Table Table Table Table Table Table Table Table 10. 11. 12. LIST OF TABLES Title of Table Cucumber fruit yield as affected by N fertilization and chlorflurenol treatments in a spring crop. , . . Effect Of chlorflurenol on cucumber fruit yield and dollar value in a spring crop ........ . . . . Effect of time of application Of chlorflurenol on cucumber fruit yield and dollar,value in a spring CFOP ............. Effect of nitrogen fertilization on cucumber fruit yield and dollar value in a spring crop ....... N03-N content in cucumber leaf petioles (percent dry weight) twenty-four hours after chlorflurenol application in a spring crop ............ N03-N content in cucumber leaf petioles (percent dry weight) taken from the five flower stage treatment. . . ........... . ....... Statistical significance of main effects and interactions for cucumber yield by weight in a spring crop Cucumber fruit yield as affected by N fertilization and chlorflurenol treatments in a fall crop ..... Effect of chlorflurenol on cucumber yield and dollar value in a fall crop ............. Effect of time of application of chlorflurenol on fruit yield and dollar value in a fall crop ..... Effect of nitrogen fertilization on cucumber fruit yield and dollar value in a fall crop ,,,,,,,, Effect of chlorflurenol on cucumber fruit number per ha (1000's) in a fall crop ,,,,,,,,,,, iv OOOOOOOOOOOOOOOOOOOO Page 11 12 13 14 16 17 18 20 21 22 23 24 Table Table Table Table Table Table Table 13. 14. 15. 16. 17. 18. 19. Title of Table Effect of time of application of chlorflurenol on cucumber fruit number per ha (1000's) in a fall crop ......................... Effect of nitrogen fertilization on cucumber fruit number per ha (1000's) in a fall crop ........ N03-N content in cucumber leaf petioles (percent dry weight) twenty four hours after chlorflurenol application in a fall crop. . . . .......... N03-N content in cucumber leaf petioles (percent dry weight) taken from the five flower stage treatment ...................... Length-diameter ratio of no. 3 grade size cucumber fruit as affected by chlorflurenol treat- ment in a fall crop .................. Statistical significance of main effects and interactions for cucumber yield by weight in a fall crop ...................... Statistical significance of main effects and inter- actions for cucumber yield by count in a fall CY‘OP .............. . .......... Page 25 26 29 3O 31 32 33 LIST OF FIGURES Title of Figure Page Figure 1. Fruit yield of cucumbers treated with chlor- flurenol when 5 female flowers were at anthesis. Planted June l0. 1975 ...... . ......... 36 Figure 2. Fruit yield of cucumbers treated with chlor- flurenol when 5 female flowers were at anthesis. Planted July l6, l975. ............... 38 Figure 3. Number of fruit produced by cucumbers treated with chlorflurenol when 5 female flowers were at anthesis. Planted July 16, 1975 ................ 40 vi INTRODUCTION As a result of labor shortages and higher labor costs, a large percentage Of the pickling cucumber crop in Michigan is being once- over destructively harvested by machine. The transition from hand to machine harvest required changes in cultural practices and cultivars. It was reported (9) that the use Of new hybrid cultivars and improved production practices increased yield from once-over mechanically harvested cucumbers within the past 5 years. However, production costs have increased over the same period and mechanical harvesting of cucumbers has resulted in only a slight increase in actual net returns to growers (9). With increased production costs, improvement in cucumber yield is needed for growers to obtain an economic return. In the once-over harvest system for pickling cucumbers, the ability of the plant to produce several fruits simultaneously would increase yield (9). However, continued cucumber fruit set is usually inhibited by seed development in the earliest set fruit and this restricts the development of additional fruit (9,15). Parthenocarpy, either genetic (26), or chemically induced (2, 4, 7, 27) overcomes this inhibition. The application of growth regulators to induce parthenocarpic fruit development in cucumber (2, lo, 23) and in many other crops is possible (14, 28). however, the results are widely varied depending on the crop and the chemical being used (2. 4, 14). The experimental morphactin "chlorflurenol" (CME-74050) and Other auxin transport inhibitors have been reported to induce parthenocarpic fruit development in cucumber and to overcome the inhibition of additional fruit set by the first set fruit (7, 10, 27). Results from previous work on cucumber treated with chlorflurenol usually indicated an increase in percentage of misshapen fruits (9). The purpose of this study was to investigate the effect Of chlorflurenol and nitrogen fertilization level on pickling cucumber yield and quality. LITERATURE REVIEW Chlorflurenol is a common name for 2-chloro-9-hydroxyfluorene-9 carboxylic acid (29). This substance and several other derivatives Of fluorene-9-carboxylic acid, collectively known as morphactins, have been the subject of scientific and practical interest as representatives of a new type of growth regulator (29, 30). The physiology and performance of these new growth regulators have been critically reviewed (29, 30) and summaries on their possible uses were provided by many authors based on preliminary tests on a world-wide scale (30). The particular characteristics of morphactins which distinguish them from other synthetic regulators were described by Schneider (29) as follows: (l) A wide growth regulatigg_concentration range and high tolerance: Experiments have shown that the nontoxic growth regulating concentration range extended over five to seven orders of magnitude depending on the particular derivative concerned. Among growth regulators, this was only equaled by gibberellic acid. (2) Favorable therapeutic index: The concentration of dosage can be adjusted to suit the purpose of the experiment or of the intended application. With other synthetic regulators, this is usually possible only within relatively narrow limits. (3) Prolonged action by overdosing: There is a possibility of regulating not only the intensity but also the duration of the action by an appropriate adjustment of the dosage. By "overloading" the plant, it is possible to achieve prolonged action similar to that Of a "depot supply". (4) Subsidence of action, recovery capability of the plant: The high tolerance and the rapid metabolic degradation of morphactins result in the fact that the treated plants are capable of resuming normal development after a dose-dependent period of inhibition. With morphactins it is possible to achieve both an induction of short- lasting "development impulses" and a prolonged inhibition for general growth control without loss of capability for final recovery of the great majority of species. (5) Differential spectrum ranges: Morphactins have a broad spectrum of action and vary within wide limits including weeds, grasses, as well as woody species. It was further mentioned (29) that the action of morphactins is systemic and slow. Modification, inhibition, and sometimes promoting effects are seen only gradually. High concentrations result in dwarfism, whereas low concentrations have a transient effect on shoot growth, branching, and the morphogenesis of new growth subsequent to the treatment. It is because of this fundamental action on the morphogenesis of plants that these new regulators were given the name "morphactins". Morphactins have been reported to cause inhibition of seed germination and seedling growth (2], 29), stem elongation growth (20, 29), and formation of shoot organs (29). They also abolish the polarity of cell division and apical dominance (29), delay bud break of dormant buds and affect many other phenomena in the vegetative growth of plants (l7, 24, 29, 30, 35, 36). Effects of morphactins on flowering have resulted in improve- ments and changes in fruit production practices, as they were reported to show promise for fruit thinning, loosening, improvement in quantity and distribution Of fruit buds (29, 30, 37, 38). Morphactins have been reported to increase the number of flowers formed in some herbaceous species and fruit trees (30, 34, 37, 38), change the sex of flowering in some monoecious crop species (6, l8, l9), stimulate parthenocarpic fruit set (7, 10, 27, 28), fruit growth, ripening, and abscission (37, 38). The use of morphactins, particularly Chlorflurenol, in cucumber was reported by many workers since the early 1970's (6, lo, 27). Robinson et al. (27) reported that foliar application Of chlorflurenol at 100 ppm induced parthenocarpic fruit development in cucumber grown under greenhouse conditions. Compared to other growth regulators, chlorflurenol was most effective in inducing parthenocarpy when applied in the flowering stage. Application Of ethephon (2-chloroethyl phosphonic acid) prior to chlorflurenol treatment, enhanced the response of the plant. However, ethephon alone applied to cucumber at anthesis was not effective in inducing parthenocarpy (9). Ethephon only increased the number of pistillate flowers, particularly on monoecious cultivars (3, 8, 9, 16). Chlorflurenol tested on cucumber grown under field conditions has been reported (9, 10). Cantliffe et al. (10) reported that chlor- flurenol at 50 and 100 ppm increased fruit production of both normally pollinated and inadequately pollinated cucumber. Application Of ethephon followed by chlorflurenol produced over twice as many fruit as controls when pollen was plentiful, and more than four times as many when pollen supply was limited. It was also reported (9) that chlorflurenol increased the proportion of fruit in the smaller, more valuable size grades, and therefore advantageous for once-over harvesting systems. Fruit shape has been affected by chlorflurenol treatments. Rudich and Rabinowitch (28) reported that tomatoes treated with chlor- flurenol at 5 ppm or higher produced a considerable percentage Of deformed fruits. Working with cucumbers, Cantliffe et a1. (10) reported that fruit of chlorflurenol treated plants were slightly Shorter, particularly in large size grades, but were still commercial- ly acceptable. In their recent report, Cantliffe and Phatak (9) suggested that application of ethephon followed by chlorflurenol will slightly improve fruit shape of pickling cucumber. However, Shannon and Robinson (31) reported that chlorflurenol at 50 and 100 ppm had no detrimental effect on fruit shape of cucumber. In a once-over harvest system of pickling cucumber production, nutrient conditions were most important to secure a good stand of the plants and maximum yields (25). Nitrogen fertilization particular- ly was reported to increase fruit yield by forming more pistillate flowers and improved fruit shape (11, 25). Combination treatments of chlorflurenol and nitrogen fertilization on cucumbers would likely improve the quality and quantity of fruit yield. MATERIAL AND METHODS Pickling cucumber (cv. Premier) containing 15 percent mono- ecious pollinator was planted in field plots on Conover loam soil at the Horticulture Research Center, Michigan State University, in 1975. The first crop (spring) was sown on June 10 and the second crop (fall) on July 16. Experimental design was a split-split plot with four replicates. Nitrogen fertilization levels were mainplots, time Of chlorflurenol treatments were subplots and chlorflurenol rates were sub-subplots. Fertilizer was disked into the seedbeds at the rate of 28-56-56 kg/ha as the soil was fitted. Plots were 2 m by 8 m with four rows 40 cm apart in each plot. Seeds were sown with a Dahlman seeder using a 5 cm in-row spacing. Following emergence the seedlings were hand thinned to obtain a uniform 120,000 plant/ha density. Chloramben methyl ester at 2.25 kg/ha was applied as a pre-emergence herbicide immediately after planting. Hand weeding kept the plots weed free. Recommended cultural practices were followed throughout the growing season to Obtain maximum yields for once-over harvest. An additional 84 kg/ha N (NH4N03) was topdressed on one half the mainplots 10 days after planting. A single full-coverage spray of chlorflurenol (CME-74050) at 0 and 250 ppm was applied with a C02 pressurized hand sprayer when S, 7, or 9 female flowers reached anthesis. The spray volume was 374 l/ha. Spray solutions were prepared immediately before applica- tion using 0.1% Regulaid as a surfactant. Leaf petiole samples for N03-N content analysis were collected randomly 24 hrs after chemical application and repeated at 48 hrs intervals three times. The petioles were rinsed with tap water and dried in a forced air oven at 38°C for 24 hrs. Petiole nitrate content was analysed by the method of Baker and Smith (1). Plots were hand harvested once when approximately 10% by weight of the cucumber fruits were judged to exceed 5.1 cm in diameter. Fruits were size graded and weighed. Dollar value was computed as follows: dollar value = $132/metric ton size 1 + $66/m.t. size 2 + $44/m.t. size 3 + $22/m.t. size 4. Size 1 fruit are 1.9 to 2.9 cm in diameter, size 2 fruit are 2.9 to 3.8 cm, size 3 fruit are 3.8 to 5.1 cm, and size 4 fruit are those greater than 5.1 cm in diameter. Dollar values were calculated using the pricing system adopted by the Pickling Cucumber Improvement Committee (PCIC), St. Charles, Illinois 60174. Length-diameter ratio was determined using 20 number 3 size fruits from each plot. RESULTS Table 1 shows the fruit yield by size grades as affected by chlorflurenol rate, time of application, and nitrogen fertilization rate for the spring crop. Tables 2, 3, and 4 show the three main effect results. Chlorflurenol at 250 ppm applied as a single spray on pickling cucumbers at flowering stage significantly increased the fruit yield in the smaller size grades (1A and 18) and reduced the fruit yield in the larger size grades (28 and 4)(Table 2). The increased yield in small fruits and the decreased yield in large fruits resulted in no significant Change in total yield or in the dollar value. Hub and crook fruits were slightly increased due to chlor- flurenol treatment, however, the difference was not significant. Time of chlorflurenol application had a significant effect on fruit yield as shown in Table 3. Earlier application resulted in a greater effect on fruit yield compared to application at the later stage Of flowering. This effect was significant in size grades no. 1A, 18, and 2A. The nub and crook fruits and also the marketable fruits were slightly increased at the five flower stage application. The PCIC dollar value was significantly greater at the earliest application compared to the later applications. 10 11 2.022 0.42 2.4 2.24 0.00 0.0 0.0 4.4 0.2 002 2.222 0.02 2.2 2.04 0.40 4.0 0.0 2.2 2. 0 0 0.002 0.22 0.4 0.42 0.00 4.0 2.0 0.0 0.2 002 0.202 2.00 0.4 0.00 2.00 2.22 0.0 2.0 2.2 0 2 2.422 0.40 0.2 4.22 0.00 0.22 0.02 0.22 0.2 002 2.242 0.00 0.0 0.20 2.20 2.02 2.0 0.0 0.2 0 0 222 0.242 2.40 2.4 0.20 0.20 0.0 0.0 0.4 2.2 002 0.022 2.40 0.4 0.20 2.00 0.02 2.02 0.4 2.2 0 0 4.002 0.02 2.0 0.02 2.04 0.0 2.02 4.0 0.2 002 0.022 2.02 0.4 4.00 0.20 0.02 0.02 0.0 2.2 0 2 0.002 2.20 2.0 2.02 0.04 0.02 4.02 0.22 4.2 002 2.022 0.02 0.4 2.04 2.00 0.22 0.0 0.2 0. 0 0 02 0 i _ 0xoocu 00005200 20002 0200 0 4 0 02 42 02 42 20000 00 2002000 00200, 0902 Focmgz_m mngopm 000002 m~00 ounce Icopgo 40 .02 -0209200 2 200200 0020 02022 .aoco mcwcam 0 :2 0ucmEumocu 2000204020250 0:0 covumwwrwucmw z 00 umpumwmm 00 04000 “0020 20020000 .2 02000 12 .20002 00000 02020200 0.00000av _0>0_ 0m 00 00000200000 00: 020 200002 005500 00 00zoppow 00E0000 :0 00040> :00: .0P0>00000002 0022 00 222 0:0 mm 0003 00~2~20202 00020 5020 00000000 .000_0> c005 02020>020 0400 00.022 02.20 02.0 02.20 02.20 00.0 00.02 00.0 00.2 002 0004 04.202 00.00 00.0 02.04 02.00 00.02 00.0 02.0 02.22. 0 202000 0-2 .t: 00 20002 0220 000020 4 0 02 42 02 02 2202200 20002 0 0002 AEnav Foams: C20 20 200202 0020 02022 .0020 022200 0 :0 0040> 202200 020 02000 00022 20050000 00 2020202220200 20 000020 .2 02002 13 .20002 00:00 02000202 0.0000000 40>02 00 00 00000200000 00: 020 0200002 005500 00 00302000 000F0> 000: .00000 000002000 020 0000020 2022 00000000 00000> c002 22020>o 200 .02000000 0000002 0203022 020202 20 20020: 000002000 :00; 0002000 003 000 20 some 00m.omp 00N.om 0®.m 0F.o¢ no.0m n N.m u m.w um.m um.— m 0000 000.222 000.02 00.4 00.00 00.20 00.0 00.0 00.0 00.2 2 0040 000.022 002.40 04.0 00.00 00.20 00.02 00.22 00.2 20000.2 200 «umumv . mup 0x002u 0; PauOH mNWm a 0 m mm 202200 000 02020 00020 20050000 00 2000202020200 00 00200022000 00 0520 20 000200 .0 02000 14 .00005 00:00 02000202 0.0000000 20>0_ 00 00 00000000020 00: 020 200002 005500 00 00302200 0050000 :2 00020> c002 .020>00000002 500 002 000 o 00 2000202020200 0023 0000020 00020 5020 00000000 00020> c002 22020>o 20 0m—m w—.omp mm.Pw mm.0 mm.m0 mm.~m 00.m m~.m mo.o mo.p NPF 0mom 0m.FNP mo.om 00.0 no.0m mo.mm mm.m 0¢.op 00.0 mm.PA« mm AuHu0v m I P mxoo2u a: pouch mem w v m mm 202200 000 0_020 00022 20050000 00 0020020200200 0000200: 00 000020 .0 02002 15 Nitrogen fertilization had no significant effect on fruit yield. Dollar value was greater at the higher nitrogen fertilization rate compared to that of the lower rate, however, the difference was not significant (Table 4). Nitrate-N content in petioles indicated that plants receiving high nitrogen fertilization contained higher N03-N compared to those receiving low nitrogen fertilization, however, the difference was not significant (Table 5 and 6). Chlorflurenol treatment did not significantly influence N03-N content in petioles compared to controls. Interactions occurred among the three main effects as indicated in Table 7. In the first order, Significant interactions were observed between rates and time Of application Of chlorflurenol in size grades no. 1A, 18, 2A, 4 and in total yield and in dollar value. Interactions between nitrogen fertilization and chlorflurenol rates were not Observed, whereas interactions between nitrogen fertilization and time of application of chlorflurenol were significant only in total 1 to 3 size grade fruits. In the second order, interactions among the three main effects were significant only in size grade no. 1A. These interactions indicate that increases in fruit yield and dollar value were primarily the result of chlorflurenol rates and time of application. 16 .0000020200202 0000202: 202 00005 00000000 00020020 2003000 00020>A00 .20000 00:00 02020002 0.2000002 20>02 20 00 00000220000 00: 020 200002 005500 00 00302202 0050200 :0 000F0> 000220 xAmm.NV0m0.2 xfiom.mv mmm.~ xAFo.NV 0m©.N 0mm 000.2 000.2 020.2 0 202 0202.20002.2 2220.20 002.2 2 x204.20 000.2 002 22.2 022.2 002.2 000.220 0 22 0 2 0 2002020 A5002 0000020000202 00000000 00 0203022 20 .02 2000202220200 20002022 .0020 000200 0 :2 00200002000 0000202220200 20020 02000 2002-000030 2000003 020 02002002 00200000 200_ 20050000 :0 0:00:00 2.002 .0 02002 17 .00000N0000200 00002000 200 00005 00000000 00000020 0003000 00000> A00 .0000» 00000 0000000: 0.0000000 00>00 00 00 00000000000 000 020 200000 005500 >0 00200000 0050000 00 00000> 0002 A0 020.2 000.2 000.2 0 200 xA0o.2v 000 0 xA00.2V 000 2 0002500.2V 0mm 2 002 020.2 022.2 000.2A0 o 02 0 m 0 E290 A5000 00000~0000200 A0000V000500020 20000 0500 0000200020000 00002002 .000500020 00000 202000 0>00 000 5020 00x00 A000003 020 00002000 00000000 0000 20050000 00 0000000 2.002 .0 00000 18 00000000000 00 0500 u 0 00>00 00 00 00000000000 002 u . 00002 0000200020000 u 000 00>00 00 00 00000000000 n + 00002 00002002 u z - u - n - u - u - + 0x000xz + + - n + s - + + + 0x000 - u + u u u n - u - 0x2 - u - - u u - u u ' 000xz + u u u n u u + + + 5 u a n n + u + n + + 000 - - - u n - u - - - z 0000 m u 0 000020 200000 00000 0N00 0 0 m 02 <2 00 <0 0000000 00000 0002 -20000 20000 000 0N00 00020 0000000 000: .0020 000200 0 00 000003 00 0000» 20050000 200 000000020000 000 0000000 0005 00 000000000000 00000000000 .2 00000 19 Results of the fall crop in most cases were similar to those of the spring crop. Table 8 shows the distribution of fruits in different size grades. The main effects of chlorflurenol, time of application, and nitrogen fertilization appear in Tables 9, l0, and ll, respectively. Chlorflurenol significantly increased the yield of size 1A, 18, 2A, and nub and crook fruit (Table 9). Earlier chlor- flurenol application produced significantly greater yields in size 1A, 18, 2A, and nub and crook fruit. Earlier chlorflurenol application also had a greater dollar value (Table l0). Nitrogen fertilization rate had no significant effect on cucumber yield or dollar value (Table 11). Table l2 shows the effect of chlorflurenol on fruit number per hectare. Chlorflurenol treatment significantly increased fruit number per hectare in size grades no. 1A, l3, and in the total fruit number. The effect of time of application on fruit number is shown in Table 13. Chlorflurenol application at the earlier flowering stage resulted in significantly greater fruit number compared to treatments at later stages of flowering. The differences were significant in size grades no. lA, lB, 2A, and in total yield. The effect of nitrogen fertilization on fruit number was not significant for any size grades (Table l4). 20 2.02 0.20 2.0 0.02 2.02 0.0 0.0 0.0 0.0 002 0.00 0.00 0.0 0.00 0.02 0.0 0.0 2.0 0.0 o 0 0.00 0.00 0.0 2.00 0.02 0.0 0.0 0.0 0.2 002 0.00 0.00 0.0 0.00 0.00 0.2 0.0 0.0 0. o 2 2.00 0.00 0.2 2.02 2.22 2.0 0.0 0.2 2.0 002 0.00 0.20 0.0 0.00 0.20 0.0 2.0 2.0 0.0 o 0 200 0.00 2.00 0.0 0.00 2.02 0.2 0.0 0.0 0.0 002 0.02 0.00 0.0 0.02 0.02 0.0 0.0 0.0 0.0 o 0 2.00 0.00 0.2 0.00 0.02 0.0 0.0 0.0 0.2 002 0.00 0.00 0.2 0.22 0.02 0.0 2.0 0.0 2.0 o 2 2.00 0.20 0.0 0.00 0.00 0.2 0.0 0.0 0.2 002 0.00 0.00 0.0 0.00 0.02 0.2 0.0 2.0 0. o 0 02 m u 0 000020 00000000 00000 0wmww 00mz 0 0 02 <2 00 <0 009mmmw0 020wM00 Amm“mww 00200 00020 -20000 00 .02 -0000200 2 200\00 0020 02002 .0020 0000 0 00 0000500020 0000200020000 000 0000020000200 2 00 00000000 00 00000 00020 20050000 .0 00000 21 .2000» 00:00 00000002 0.0000000 00000 00 00 00000000000 00: 020 200000 005500 00 00300000 0050000 00 00000> c002 .000>00000002 00\z 0x 200 000 02 0003 0020000200 00000 5020 00000000 000000 0005 00020>0 A0 0000 00.00 02.00 00.0 00.00 00.02 02.0 00.0 00.0 02.2 002 0002 00.00 00.00 02.0 00.00 00.22 00.0 00.0 02.0 00.000 0 000000 0 - 0 000020 00 00000 0200 0 0 0 02 02 00 <0 2200000 00000 0002 05000 200\00 0000 000020 0000200020000 .0020 0000 0 00 00000 200000 000 00000 00020 20050000 00 0000200020000 00 000000 .0 00000 22 .00000 00000 0000000: 0.0000000 00>00 00 00 00000000000 000 020 200000 005500 00 00300000 0050000 00 000000 000: .00000000 0000002 0203000 000500 0 20 .2 .0 0003 0000200 00000 000002000 000 0000020 000 5020 00000000 00000> 0005 00020>000 0002 00.02 00.00 00.0 02.20 00.02 00.0 02.0 00.0 .02., 0 0000 000.00 000.20 00.0 00.00 00.02 00.0 00.0 00.0 02.0 2 0000 00.20 00.20 00.0 02.00 00.02 00.0 00.2 00.0 00.200 0 000000 0 - 0 000020 .00 . . 0 0. e ._ 000200 0000 020020 0203000 00 .oz .0020 0000 0 00 0000> 200000 000 00000 00020 20050000 00 0000200020000 00 00000000000 00 0500 00 000000 .00 00000 23 .00000 00001 0000000: 0.0000000 00>00 00 00 00000000000 000 020 200000 005500 00 00300000 0050000 00 00000> 000: .000>00000002 500 omm 000 o 0000200020000 0003 0000020 00000 5020 00000000 00000> 0005 00020>oA0 000m 0m.0w 0m.00 0_.m 0F.mm 0F.NN 0m.m 0m.m 00.0 00.— N—P 0mpm 00.0w 0m.m0 00.m 00.0m 0m.mm 0m.© 0m.m 0m.m 0m._fl« mm AuHuav m n F mx002u . 0: PMHOH wNwm a v m mm 200000 000 00000 00020 20050000 00 0000020000200 00002000 00 000000 .00 00000 24 .00000 00000 0000000: 0.0000000 00>00 00 00 00000000000 000 020 200000 005500 00 00300000 0050000 00 00000> 000: .0_0>00000002 00\z 00 N00 000 mm 0003 0020000200 00000 5020 00000000 00000> 0005 00020>oA0 00.000 00.000 00.0 00.00 0m.- 00.o— 00.0m 00.00 02.00 omm 0m.mm_ 02.000 0N.2 00.00 02.mm 00.00 0N.20 00.0N 0o.mNA« o m u 0 000020 00000 0200 0 0 0 mm 00 00 00 00000000000 000 020 200000 005500 20 00300000 0050000 00 00000> 0002 .00000000 0000002 0203000 000500 m .00 2m .m .553 thmxam muo _.Q Uwumokucz ficm vmummxu $03. 50.0% Umcwmuno mm: Pm> Saws Fpmxm>on£ um.mm— um.oop np.m no.m_ 0N.mm mo.m ow.mp uo.mN uo.mm m 0m.m0~ no.m_— am.“ amm.©~ 0w.NN mm.m am.mp nm.mm np.mm m 0m.m- 0N.Nm~ 0m.o— 0m.m_ 0N.mm mm.mp 0m.mm 0N.m0 0m.m0A« m M: P meOLQ 00002 mnwm w 0 m mm 00 00 00 00000000000 000 020 200000 005500 20 00300000 0050000 00 00000> 0002 .000>00000002 500 omm 000 o 0000200020000 0003 0000020 00000 5020 00000000 00000> 0005 00020>o00 00.002 00.022 00.2 02.22 00.02 02.0 00.22 00.00 00.00 222 02.002 02.202 00.0 02.02 02.22 00.22 00.02 02.20 00.0020 02 m .. _. 8.095 20000 0200 0 0 0 02 02 02 02 20000. 0002 2002000 00200 00020 0020020200200 2 .0020 0000 0 02 00.00000 00 200 200500 00020 20050000 00 0000020000200 00002000 00 000000 .00 00000 27 Data for N03-N content in petioles appears in Table 15 and Table 16. As in the spring crap, N03-N content in petioles was higher in plots receiving higher nitrogen fertilization, however, the difference was not significant. No significant differences in N03-N content was apparent due to chlorflurenol treatment (Table 15). Chlorflurenol significantly reduced the L/D ratio of no. 3 grade fruit when applied at the 5 and 7 flower stage (Table l7). Nitrogen fertilization rate did not influence L/D ratio. As in the spring crop, interactions occurred among the three main effects. Table 18 and Table 19 show their interactions expressed as fruit yield by weight and by count respectively. As indicated in Table 18, in the first order, significant interactions occurred between chlorflurenol rate and time of application for size grades no. 1A, 18, and 2A. No significant interactions were observed between nitrogen fertilization and chlorflurenol rate or between nitrogen and time of application of chlorflurenol. In the second order, interactions among the three main effects were not significant in any size grades. In Table 19, first order interactions were significant between chlorflurenol and time of application for size grades no. 1A, 13, 2A, nub and crook, total sizes 1 to 3, and total yield. In the second order, interactions among the three main effects were significant 28 only for nub and crook fruits. It can be concluded, therefore, that increases in fruit yield were primarily due to chlorflurenol and time of application. 29 .0000000—00200 00002000 200 00005 00000000 00000020 0003000 00000>A00 A0000 00000 00000002 0.0000000 00>00 0m 00 00000000000 000 020 200000 005500 00 00300000 0050000 00 00000> 0002A00 xawo.~v 000.N x000.mv 0mm.~ xamm.~v 0mm.~ 0mm 000.m 000.N 000.0 0 N00 x000.00 000.0 x000.00 000.0 0HA00.NV 000.0 000 000.0 000.N 0om.~ A0 0 A0 mm 0 0 0 00000 000\000 0000000000200 00000000 00 020300» 00 .02 0000200020000 00002002 .0020 0000 0 00 00000000000 0000200020000 20000 02000 2000 000030 A00m003 >20 0000200v 00000000 0000 20050000 00 0000000 zumoz .mP 00000 30 .0000000000200 00002000 200 00005 00000000 00000020 0003000 00000> A00 .A0000 00000 0000000: 0.0000000 00>00 00 00 00000000000 000 020 200000 005500 00 00300000 0050000 00 00000> 0002 A0 x000.00 0.0.0 x000.00 000.0 x000.00 000.0 000 000.0 000.0 000.0 0 000 x00_.00 000.0 x00_.0v 000.0 000000.00 000.0 000 0_0.0 000.0 000.000 0 00 0 0 0 00000 000\000 0000000000000 A0000V 000500020 20000 0500 0000200020000 00002002 .000500020 00000 203000 0>00 000 5020 00000 0000003 020 00002000 00000000 0000 20050000 00 0000000 2.002 .00 00000 31 .00>00 00 00 00000000000 000 .00000> 000000020 0 000 00 00005 .0000000000200 2 00 000000 000 .00>00 00 00 00000000000 .A0302 0000030 00000000000 00 0500 00 000000 .00000 00 00 00000000000 .00>0_ 00002000 0000 200 0050000 000003 0000200500 0000200020000 00 000000 00 00.0 x00.00 00.0 x00.00 00.0 x00.00 00.0 000 00.0 00.0 00.0 0 000 A E0.0 x00.00 00.0 x00.0v 00.0 x00.00 00.0 000 .3, 00.0 00.0 00.000 0 00 00002002 0 0 0 200 A5000 A00\0xv 0002 0000000020000 0000000000200 2 00000000 00 0203000 00 .02 .0020 0000 0 00 000500020 0000200020000 00 00000000 00 00020 20050000 0000 00020 0 .00 00 00002 20005000i000000 .00 00000 32 00>00 00 00 00000000000 000 00000000000 00 0500 I 0 mmHML PocmL: :LOFSU .- 4.0—0 00>00 00 00 00000000000 u + 00002 00002002 u z . I . I I . I I I I 0x00uxz I I I I I I I + + + 0x000 I I I I I I I I I I 0x2 I I I I I I I I I I 000x: + I I + I I I + + + ._. I I I I I I I + + + 000 I I I I I I I I I I z m I 0 000020 000000 00000 0000 w 0 0 mm <0 00 <_ 0000000 200000 00000 00mz, -20000 20000 0000 00020 00000WM00002 000003 00 00000 00050000 200 000000020000 000 0000000 .0020 0000 0 00 £00 00 8000.00.20.00 00000000000 .2 00000 33 00000000000 00 0500 u 0 00>00 00 00 00000000000 002 n - 00002 0000000020000 0 000 00>00 00 00 00000000000 u + 00002 00002002 I z - - + - - - - - 0000002 + + 0 I I + + + 0x000 - - - - - - - - 002 - - - - - - - - 00002 I + + I I + + + h + + I I I I + + 000 - - - - - - - - z m I 0 000020 000000 00000 0000 0 0 00 00 00 <0 0000000 200000 00000 00021 -20000 20000 0000 00020 00000WM00002 .0020 0000 0 00 00000 00020 00 00000 20050000 200 000000020000 000 0000000 0005 00 00000000000 00000000000 .00 00000 DISCUSSION Foliar application of chlorflurenol (CME-74050) at 250 ppm on pickling cucumber (cv. Premier) at the flowering stage was found to increase the yield of valuable small sized fruits and reduced the yield of the larger, less valuable fruits. In both the spring and fall crops, the effect of the chemical was significant. The chemical was also found to reduce the L/D ratio of the larger fruits and slightly increased the percentage of misshapen fruits. In this study, two levels of nitrogen fertilization were given to the plants and three different dates of chlorflurenol application were employed. Results indicated that the effect of chlorflurenol was much greater than those of nitrogen fertilization. Interactions were found between chlorflurenol and time of application, however, interactions with nitrogen fertilization were not observed. In both crops. application of chlorflurenol at the five flower stage resulted in the greatest effect on cucumber yield. The yield of 1A and lB grade fruit was doubled, and yield of 2A increased by 30% over the controls. Yield of no. 4 grade fruit was reduced significantly (Fig. l and Fig. 2). All plots in both crops were planted on the same day and harvested on the same day. Therefore, it is evident that chlorflurenol treatment reduced the rate of growth of the earliest set fruit since 34 35 Figure l. Fruit yield of cucumbers treated with chlorflurenol when 5 female flowers were at anthesis. Planted June l0, l975. I! O O 0 new (100 KG/HA) 3 3O 20 ‘IB 2A 36 crooks 37 Figure 2. Fruit yield of cucumbers treated with chlorflurenol when 5 female flowers were at anthesis. Planted July 16, 1975. u 0 /HA) & O YIELD (IOO KG 0 38 cmonnuuuon. $3??? 2 50 P PM I CONTROL 39 Figure 3. Number of fruit produced by cucumbers treated with chlorflurenol when 5 female flowers were at anthesis. Planted July l6, l975. 0r nun /HA (1000) 70 60 00000 IIIIII ooooo ...... ..... ...... ..... IIIIII ..... ...... ..... cccccc ......... a . ..... 000000 .......... o ........... ..... ...... o:l:.:.:o:u ........... ...... ..... ........... 000000 40 ''''''''' ..... ooooo ..... IIIIIIIIII '''''''''' OOOOOOOOOOO ..... 00000 .......... .......... .......... IIIIII OOOOOO .......... ..... ........ IIIIIIIIIII OOOOOO I I C ........ 00000 ..... IIIIIIIII I. 000000 ..... ........ ...... ..... IIIIII 13 2A 001:0: 23 SIZE $535533; C H LOR F LURE NOI. 2 5 0 r m l CONTROL 41 yield of no. 4 fruit was reduced. It has been suggested that the mode of action of chlorflurenol is auxin transport inhibition (2). These results support this explanation of mode of action. Auxin is normally produced in the first set fruit and translocated out of that fruit to prevent development of additional fruit on the cucumber plant (2). Late application of chlorflurenol at the nine flower stage had less effect than earlier application. This was apparently due to the large size of first set fruit at the time of application and the short interval between chemical application and harvest. First set fruits were 2.5 to 3 cm in diameter at the time of treat- ment for the nine flower stage of application. Fruit number produced per hectare indicated that chlorflurenol applied at the five flower stage increased the yield of 1A and lB grade fruit more than 300%, of 2A grade fruit more than 75%, and of 28 more than 15%, resulting in a total increase of approximately 80% over the controls (Fig. 3). Results from the later applications were less than the above figures, so in this study the five flower stage was the most suitable time for chlorflurenol applica- tion to obtain maximum fruit production in the Premier cultivar. Previous work suggested the 6 to 8 flower stage for cvs. Pioneer and Pickmore (9), or to spray the plants l to lo days after anthesis (for cv. Pioneer) (31). Premier, Pioneer and Pickmore cultivars are predominantly 42 female. Normally the first and sometimes the second flowers are female and then one to four or five male flowers develop on the main stem of the plant before more female flowers are produced. Seed quality and the degree of environmental stresses influence the field sex expression (5, l2). The optimum time for chlor- flurenol application and the response to chlorflurenol on these comercial predominaitly female cultivars will vary depending upon the sex expression of the plants. An increase in maleness will increase the time from the onset of flowering until five, seven, or nine female flowers are at anthesis. Delay in achieving seven or nine female flowers at anthesis allows the first set fruits to enlarge to the 2.5 to 3.5 cm diameter size and the effect of chlorflurenol on yield is reduced. This occurs since the early crown set fruit enlarge to 5.l cm in diameter in three to four days after chlorflurenol treatment requiring harvest to avoid a large percentage of oversized. worthless fruit. Dutch workers (l3, l5, 32) have reported large yield increases from chlorflurenol applications on pickling cucumber. Cultivars used were gynoecious and, since no pollen is produced, crown fruit set would not be a problem and timing of chlorflurenol application would be less critical. with no pollen present gynoecious cucumber plants produce a large number of flowers that remain on the plant and may develop parthenocarpically after chlorflurenol is applied. Timing of chlorflurenol application on predominantly female hybrid cucumbers should probably be based on crown fruit size rather 43 than number of female flowers at anthesis. From data and observa— tions in this research, chlorflurenol application would produce maximum positive yield effects if applied when crown fruits attain 1.5 to 2 cm in diameter. Chlorflurenol reduced the L/D ratio of no. 3 size fruits. Nitrogen fertilization did not overcome that undesirable chlorflurenol effect on fruit L/D ratio. Application of ethephon prior to chlorflurenol treatments has been reported to lessen the reduction in L/D ratio (9). Nitrogen fertilization had no significant effect on fruit yield and it was apparent that higher nitrogen rates did not overcome the undesirable effect of chlorflurenol which causes an increase in nub and crook fruits. Controversial results have been reported concerning chlorflurenol and misshapen fruits (9, 31). Reports from the Dutch group (l3, 15, 32), using gynoecious cultivars, were that the best results with chlorflurenol treatment were obtained from extremely low rates of nitrogen fertilization. However, low nitrogen rates were used primarily to control vine vigor with the absence of fertilized fruit on the vine. Chlorflurenol increased the PCIC dollar value in both the Spring and the fall crops. The increase was greater with earlier chlor- flurenol application. Increases in dollar value were attributable to the higher yields of the smaller size grade fruit. Previous work reported similar results (9). 44 As a general consideration, in a once-over mechanical harvest- ing system for cucumbers, application of chlorflurenol at flowering stage increases the fruit yield and dollar value. The yield increase would have been much greater if the cucumber plants were highly female. Also, the optimum time of application would probably be at a later stage of plant develOpment (about 5 to 7 female flowers) since rapid sizing of early set crown fruit would be less of a problem. SUMMARY AND CONCLUSION Use of the morphactin "chlorflurenol" in production of pickling cucumbers was tested by field plot experiments in 1975. Plots were 2 by 8 m with four rows 40 cm apart in each plot. Seeds of "Premier" were sown in 4-row beds to provide 120,000 plants/ha. Experimental design was a split-split-plot with four replicates. Nitrogen fertilization levels were mainplots, time of chlorflurenol treatments were subplots, and chlorflurenol rates were sub-subplots. Recommended cultural practices were followed throughout the growing season to obtain maximum yield for once-over harvest. A single full coverage spray of chlorflurenol at 250 ppm was applied with a COZ-pressurized hand sprayer when 5, 7, or 9 female flowers reached anthesis. Leaf petiole samples for nitrate nitrogen content analysis were collected at three different times beginning 24 hours after chemical application. Plots were hand harvested once when l0% by weight of cucumber fruits were judged to exceed 5.1 cm in diameter. The PCIC grade sizes and dollar values were used for evaluation of the yields. Chlorflurenol applied at 250 ppm when 5 female flowers reached anthesis was effective in increasing cucumber yield. Yield by weight and by count of smaller fruits was significantly increased, resulting in more marketable fruits and higher dollar value. Application of chlorflurenol at the later stage of flowering was less effective in increasing yield and dollar value. Chlorflurenol slightly increased the formation of deformed fruits and reduced the L/D ratio of the fruit. Nitrogen fertilization 45 46 level did not significantly influence the percentage of deformed fruits or the L/D ratio. l0. LITERATURE CITED Baker, A. S. and R. Smith. 1969. Extracting solution for potentiometric determination of nitrate in plant tissue. J. Agr. Food Chem. l7: 1284-l287. Beyer, E. M., Jr. and B. Quebedeaux. l974. Parthenocarpy in cucumber: mechanism of action of auxin transport inhibitors. J. Amer. Soc. Hort. Sci. 99: 385-390. Bhandary, K. R., K. P. V. Shetty, and G. S. Sulikeri. 1974. Effect of ethrel(2-chloroethyl phosphonic acid) on the sex expression and yield of cucumber (Cucumis sativus L.). Prog. Hort. 6: 49-57. Cantliffe, D. J. l972. Parthenocarpy in cucumber induced by some plant growth regulating chemicals. Can. J. Plant Sci. 52: 78l-785. l974. Sex expression in cucumbers. Factsheet. Ontario Minist. of Agr. & Food. 74-007. in Hort. Abstr. 45. 1975. l974. Alteration of growth and flowering habit in cucumber by chlorflurenol. Can. J. Plant Sci. 54: 771-726 1974. Promotion of fruit set and reduction of seed number in pollinated fruit of cucumber by chlorflurenol. HortScience 9: 577-578. and S. C. Phatak. 1974. Response of cucumber to soil and foliar application of ethephon. HortScience 9: 465-466. and . l975. Use of ethephon and chlor- flurenol in a once-over pickling cucumber production system. J. Amer. Soc. Hort. Sci. 100: 264-267. , R. N. Robinson, and S. Shannon. 1972. Promotion of cucumber fruit set and development by chlorflurenol. HortScience 7: 4l6-418. 47 ll. 12. l3. 14. 15. 16. 17. 18. 19. 20. 21. Dearborn, R. B. 1936. Nitrogen nutrition and chemical composi- tion in relation to growth and fruiting of the cucumber plant. Cornell Univ. Agr. Exp. Sta. Mem. 192. Cummins, T. L. and D. u. Kretchman. 1975. Moisture stress relations to growth and development of the pickling cucumber. Ohio Agr. Res. & Dev. Ctr. Bl: 23-24. De Vries, K. J. 1976. Economical aspects on cultivation for mechanical harvesting of pickles. Paper, presented at the European Division Conference of Pickle Packers International Inc. Paris. Elassar, G., J. Rudich, and N. Kedar. l974. Parthenocarpic fruit development in muskmelon induced by growth regulators. HortScience 9: 579-580. Hartog, J. A. 1976. Possibilities with regard to mechanical once-over harvest of pickling cucumbers in Eurooe and the use of curbiset in combination with entirely female flowering hybrids. Paper, presented at the European Division Conference of Pickle Packers International Inc., Paris. Iwahori, S., J. M. Lyons, and O. E. Smith. 1970. Sex expression in cucumber plants as affected by 2-chloro- ethyl phosphonic acid, ethylene, and growth regulators. Plant Physiol. 46: 412-415. Kaushik, M. P. and G. Prakash. 1971. Effect of some plant growth regulators on the foliar abscission in Cathanthus roseus (L.) G. Don. Plant Sci. 3: 48-51. and A. K. Bisaria. 1973. Influence of morphactins on sex expression in Luffa acutanguja Roxb. J. of Expt. Bot. 24: 921-922. and J. K. Sharma. 1974. Combined effect of day length and morphactin on sex expression in bitter gourd, Momordica charantia L. Indian. J. of Exp. Biol. 12: 599-600. Krelle, E. 1970. Interaction of morphactin with gibberellic acid in whole plants and in the rooting of cuttings. Biol. Plant.Prague 12: 256-264. Linke, R. D. and N. G. Marinos. 1970. Effect of a pregermina- tion pulse treatment with morphactin on Pisum Sativum. Aust. J. Biol. Sci. 23: 1125-1131. 48 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 49 McMurray, A. L. and C. H. Miller. 1968. Cucumber sex expression modified by 2-chloroethane phosphonic acid. Science 162: 1397-1398. Palevitch, 0., E. Pressman, and J. Rudich. 1972. Induction of parthenocarpy by Triiodobenzoic acid in Cucumbers (Cucumis sativus L.). Z. Pflanzenphysiol. 67: 457-459. Parups, E. V. 1970. Effect of morphactin on the graphimorpism and the uptake, translocation and spatial distribution of indol-3yLacetic acid in plant tissues in relation to light and gravity. Physiol. Plant. 23: 1176-1186. Pettiet, J. V. 1971. Fertility requirements for mechanically harvested cucumbers. Miss. Farm Res. 34: 7-8. Pike, L. M. and C. E. Peterson. 1969. Inheritance of partheno- carpy in the cucumber (Cucumis sativus L.). Euphytica 18: 101-105. Robinson, R. M., D. J. Cantliffe, and 5. Shannon. 1971. Morphactin-induced parthenocarpy in the cucumber. Science 171: 1251-1252. Rudich, J. and H. D. Rabinowitch. 1974. The effect of chlor- flurenol on set and concentrated yield of processing tomatoes. HortScience 9: 142-143. Schneider, G. 1970. Morphactins: Physiology and Performance. Ann. Rev. Plant Physiol. 21: 499-536. . 1973. Morphactins in fruit growing: early indications. Acta Hort. 34: 497-507. Shannon, S. and R. w. Robinson. 1976. The use of chlorflurenol in production of pickling cucumbers. HortScience 11: 476-478. SliJkerman, Th. C. 1976. Some information and results of 1976 about mechanical once-over harvest with BMG and Wilde machines of gynoecious pickling cucumbers induced with curbiset. Paper presented at the European Division Conference of the Pickle Packers International Inc. Paris. Tiedjens, V. A. 1926. Some observations on the response of greenhouse cucumber (Cucumis sativus) to certain environmental conditions. 'Proc. Amer. Soc. Hort. Sci. 23: 184-189. 34. 35. 36. 37. 38. 50 Tjia, B., D. C. Kiplinger, and P. C. Kozel. 1973. Studies of morphactin on the growth and auxin distribution on Chrysanthemum morifolium Ramat. J. Amer. Soc. Hort. Sci. Treichel, S. 1974. The influence of morphactins on the metabolism of higher plants. I. The effect on respiration and on some glycolytic enzymes. Bio. und Physiol. der Pfl. 166: 481-493. 1974. The influence of morphactins on the metabolism of higher plants. 11. The effect on photosynthesis and on starch, ATP and chlor0phy11 contents. Bio. und Physiol. der Pfl. 166: 495-509. Weaver, R. J. and R. M. Pool. 1968. Induction of berry abscission in Vitis vinifera by morphactins. Amer. J. Enol. Vitic. l9: lZl-l24. and . 1968. Morphactins induced berry ab- scission’ih grapes. Calif. Agr. 22: 10-11. “IIIIIIIIIIIIIIIIII