Ethephon (2-chloroethyl phosphonic acid) at 0, 125, 250 and 500 ppm was applied as spray to Beauty Seedless grapes on dormant vines after pruning, after berry set and at veraison. Ethephon (500 ppm) application at veraison improved the quality by increasing total soluble solids to acid ratio and colour development and by reducing the acidity. This treatment also enhanced ripening and reduced the duration of harvest.Der Einfluß von Ethephon (2-Chloräthylphosphonsäure) auf die Qualität und Reife der Rebensorte Beauty SeedlessEthephon (2-Chloräthylphosphonsäure) wurde, neben einer Kontrollbehandlung, in den Konzentrationen 125, 250 und 500 ppm auf Reben der Sorte Beauty Seedless gesprüht; die Behandlung erfolgte nach dem Schnitt noch während der Dormanz, nach dem Beerenansatz und beim Weichwerden der Beeren. Anwendung von 500 ppm Ethephon während des Weichwerdens verbesserte die Traubenqualität durch Erhöhung des Zucker/Säure-Verhältnisses, durch Steigerung der Farbstoffausbeute und durch Abbau der Säure. Diese Behandlung beschleunigte auch die Reife und verkürzte die Dauer der Ernte

Chundaway, B. S.

Mehta, P. K.

English

JKI Open Journal Systems (Julius Kühn-Institut)

Vitis 18, 117-121 (1979) Department of Hortlculture, Haryana Agricultural University, Hissar, Haryana, India Effect of Ethephon (2-chloroethyl phosphonic acid) on quality and ripening of Beauty Seedless grape by P. K. MEHTA and B. S. CHuNDAWAT Der Einfluß von Ethephon (2-Chloräthylphosphonsäure) auf die Qualität und Reife der Rebensorte Beauty Seedless Z u s a m m e n f a s s u n g . - Ethephon (2-Chloräthylphosphonsäure) wurde, neben einer Kontrollbehandlung, in den Konzentrationen 125, 250 und 500 ppm auf Reben der Sorte Beauty Seedless gesprüht; die Behandlung erfolgte nach dem Schnitt noch während der Dormanz, nach dem Beerenansatz und beim Weichwerden der Beeren. Anwendung von 500 ppm Ethephon während des Weichwerdens verbesserte die Traubenqualität durch Erhöhung des Zucker/Säure-Verhältnisses, durch Steigerung der Farbstoffausbeute und durch Abbau der Säure. Diese Behandlung beschleunigte auch die Reife und verkürzte die Dauer der Ernte. Introduction Uneven ripening is one of the serious problems in Beauty Seedless grape, which is an early cultivar recommended for commercial cultivation in north India. Ethe-phon has been found effective in accelerating the ripening and improving the quality of many fruits (EcK 1970, GERDITS and ÜBENAUF 1972, CHUNDAWAT et al. 1977). Dipping experiments with Ethephon have resulted in enhanced anthocyanin development and an increase in total soluble solids to acid ratio in Doradillo grapes (HALE et al. 1970). RAo et al. (1974) reported that ripening response of Ethephon in Pusa Seedless (Sultanina) grape varies with stage of treatment. Looking at the use-fulness of this chemical on grapes, the present study was designed to work out the proper concentration of Ethephon with standard timings of its application for uni-form colour development and early maturity of Beauty Seedless grapes. Materials and methods 8-year-old vines of Beauty Seedless growing in the Experimental Vineyard of the Department of Horticulture, Haryana Agricultural University, Hissar, were used. The vines were trained on double wire Kniffin and spur-pruned to 2 buds (Jan. 21, 1976). To maintain uniformity, 20 canes/vine were retained. Ethephon at the con-centration of 0, 125, 250 and 500 ppm was applied as dormant spray after 3 weeks of pruning (S1), after berry set (S2) and at veraison (S3). Control vines were sprayed with water containing wetting agent (Tween-20). Each treatment consisted of a single vine replicated 3 times in a randomised block design. Altogether 36 vines were used in the experiment. Ripe berries were used to determine the berry weight and 118 P. K. MEHTA and B. S. CttuNDAWAT percent juice. Total soluble solids were determined by hand refractometer and total acidity by titrating the juice against n/10 NaOH from the berries harvested at opti-mum harvest. To determine the colour intensity, the extraction and measurement methods described by S1NGH (1976) were followed. Results and Discussion Berry weight Ethephon increased the berry weight significantly when applied as dormant spray. Ethephon applied at berry set and veraison did not show any significant ef-fect on berry weight (Table 1). J ENSEN et al. (1973) also observed that berries treated with Ethephon did not show any effect on berry weight in table grapes. The in-crease of berry weight by dormant spraying Ethephon in the present investigation Table 1 Effect of Ethephon on berry weight and juice content in Beauty Seedless grape Der Einfluß von Ethephon auf Beerengewicht und Saftmenge der Sorte Beauty Seedless Ethephon Berry wt. (g) Juice('/,) conc. (ppm) S1 S2 Sa Mean S1 S2 Sa Mean 0 1.5 1.4 1.5 1.47 56.9 61.5 58.7 58.9 125 1.6 1.5 1.5 1.53 58.3 60.4 59.8 60.5 250 1.7 1.3 1.5 1.50 57.3 59.6 60.4 60.0 500 1.6 1.2 1.4 1.40 56.9 59.9 58.5 55.0 Mean 1.6 1.4 1.4 57.3 59.6 61.1 C.D. at5 % For stages 0.13 2.2 For concentration NS NS For interaction NS NS Table 2 Effect of Ethephon on TSS and acidity in Beauty Seedless grape Der Einfluß von Ethephon auf TSS- und Säure-Gehalt der Sorte Beauty Seedless Ethephon TSS (1/o) Acidity ('lo) conc. (ppm) S1 S2 Sa Mean S1 S2 S3 Mean 0 16.1 13.9 14.0 14.6 0.88 1.24 1.21 1.11 125 16.0 16.3 16.9 16.4 0.86 0.87 0.78 0.84 250 16.0 16.6 17.2 16.6 0.84 0.85 0.75 0.81 500 16.1 16.8 17.4 16.8 0.84 0.82 0.73 0.80 Mean 16.05 15.90 16.37 0.86 0.95 0.87 C.D. at5 % For stages 0.06 0.02 For concentration 0.07 0.02 For interaction 0.12 0.04 Effect of Ethephon on quality and ripening of grapes 119 may possibly be due to longer retention of berries on the vines as compared to other stages of treatment. Juice content Percent juice in grape berries was increased when Ethephon was applied at berry set and at veraison (Table 1). Similarly table grapes treated with Ethephon were also found to be juicier than untreated control without affecting the juice quality adversely (JENSEN et al. 1973). TSS Ethephon applied after berry set and at veraison increased the percent soluble solids in grape juice (Table 2). The most effective treatment was 500 ppm when applied at veraison. WEAVER and Pom (1971) also observed a significant increase in total -soluble solids in Carignane grapes when Ethephon was applied at the be-ginning of colour development. Acidity Total acidity of Beauty Seedless grape juice was significantly reduced by all the treatments with Ethephori (Table 2). The greatest reduction was found in berries treated with 500 ppm of Ethephon at veraison. Decreased acidity in wine cultivars of grapes with Ethephon has also been reported by WEAVER and MoNTGOMERY (1974). TSS/acid ratio TSS/acid ratio was remarkably increased by Ethephon applied at veraison fol-lowed by the treatment given after berry set (Table 3). The differences were reduced by both acidity and increased TSS. WEAVER and MoNTGOMERY (1974) reported in-creased TSS/acid ratio by Ethephon in Ruby Cabemet grape mainly due to reduced acidity. Colour The development of colour in berries was enhanced by Ethephon when berries were treated after berry set and at veraison. 500 ppm at veraison was the most ef-fective treatment (Table 3). The overall increase in colour with Ethephon applica-Table 3 Effect of Ethephon on TSS/acid ratio and colour development in Beauty Seedless grape Der Einfluß von Ethephon auf das TSS/Säure-Verhältnis und die Farbstoffentwicklung der Sorte Beauty Seedless Ethephon TSS/acld ratio Colour (absorbance at 530 nm) conc. (ppm) S1 S2 Sa Mean S1 S2 Sa Mean 0 18.2 11.1 11.1 13.6 0.43 0.41 0.40 0.41 125 18.5 18.8 21.5 19.6 0.46 0.60 0.68 0.56 250 19.0 19.6 22.8 20.5 0.49 0.62 0.67 0.60 500 19.2 20.5 23.6 21.1 0.49 0.64 0.77 0.63 Mean 18.7 17.5 19.8 0.47 0.56 0.63 C.D. at5 % For stages 0.50 0.018 For concentration 0.58 0.015 For interaction 1.01 0.03 120 P. K. MEHTA and B. S. CHuNDAWAT Table 4 Effect of Ethephon on ripening in Beauty Seedless grape Der Einfluß von Ethephon auf die Reife der Sorte Beauty Seedless Optimum date of harvest Duration of harvest (d) Treatment S1 S2 S3 S1 S2 Sa Control 7th June 7th June 7th June 6 6 6 Ethephon 125 ppm 7th June 27th May 30th May 6 3 2 Ethephon 250 ppm 7th June 26th May 30th May 6 3 2 Ethephon 500 ppm 7th June 26th May 29th May 6 3 2 tion would be specially useful in varieties and locations where natural colour devel-opment is poor. An increased colour development in Emperor grapes has also been observed by WEAVER and PoOL (1971) with Ethephon. Ripening Dormant spray did not alter the dates for optimum ripening (Table 4). How-ever, Ethephon application after berry set and at veraison enhanced ripening by 13 and 10 d, respectively. Whereas duration of harvest was 7 d under control and dor-mant spray treatments, it was reduced to 2 to 3 d in Ethephon application after berry set and at veraison. These effects have been mainly due to the effect of ethyl-ene, released by Ethephon, which is known as fruit ripening hormone which helped in early attainment of optimum TSS/acid ratio and early colour development. Simi-lar results have been obtain~d by HALE et ai. (1970) in Doradillo and Shiraz grapes and RAo et al. (1974) in Pusa Seedless grapes. Summary Ethephon (2-chloroethyl phosphonic acid) at 0, 125, 250 and 500 ppm was applied as spray to Beauty Seedless grapes on dormant vines after pruning, after berry set and at veraison. Ethephon (500 ppm) application at veraison improved the quality by increasing total soluble solids to acid ratio and colour development and by re-ducing the acidity. This treatment also enhanced ripening and reduced the dur<1tion of harvest. References CHuNDAWAT, B. S., S1NGH, I. s. and CHnKARA, S. D., 1977: Effect of pre-harvest application ot 2-chloroethyl phosphonic acld (Ethrel) on ripenlng of two cultlvars of plum. Haryana J. Hort. Sei. 6, 24-26. EcK, P., 1970: Influence of Ethrel upon highbush blueberry ripening. HortScience 5, 23-25. GERoITs, M. and OeENAUF, G., 1972: Effects of preharvest applications of ethephon on maturatlon and quality of Calimyrna figs. Calif. Agricult. 26 (5), 8-9. HALE, C. R., CooMee, B. G. and HAWKER, J . S., 1970: Effect of ethylene and 2-chloroethyl phos-phonic acid on the ripening of grapes. Plant Physiol. 45, 62~23. JENIEN, F. L., K1ssLEn, J. I., Luv1sTI, D., PEAcocK, B., HAsLEY, D. and LEAVITT, G. M., 1973: Effect of Ethephon on table grapes. Blue Anchor 50, 16-18. RAo, M. M., PANDEY, R. M. and Sn,cH, R. N., 1974: Effect of Ethrel on Pusa Seedless grape. S. Indian Hort. 22, 112-115. Effect of Ethephon on quality and ripening of grapes 121 S1NGH, I. s., 1976 : Natural ethylene evolution in grape vine and lts manipulatlon by cultural operatlons and growth regulators. Ph. D. Thesis, Haryana Agricult. Univ. WEAVHR, R. J . and MoNTGOMERY, R. , 1974 : Effect of Ethephon on coloration and maturation of wine grapes. Amer. J. Enol. Vlticult. 25, 39-41. - - and PooL, R. M., 1971 : Effect of 2-chloroethyl phosphonic acid (Ethephon) on maturatlon of Vitis vlnlfera. J. Amer. Soc. Hort. Sei. 96, 725--727. Eingegangen am 24. 10. 1978 P. K. MEHTA Ph. D. Student Dr. B. S. CHuNDAWAT Horticul turist Department of Horticulture Haryana Agricultural University Hissar, Haryana India 

Effect of Ethephon (2-chloroethyl phosphonic acid) on quality and ripening of Beauty Seedless grape

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Effect of Ethephon (2-chloroethyl phosphonic acid) on quality and ripening of Beauty Seedless grape

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