Effect of Pre-Harvest Treatment on Yield, Maturity and Quality of Flame Seedless Grape (Vitis vinifera L.)

To improve fruit quality in grape cv. Flame Seedless, application of Ethephon (400 and 500 ppm) and trunk girdling was done at veraison stage. Cluster thinning was done by retaining 100, 75 and 50% of total number of bunches on the vines, and, the rest were removed immediately after full bloom. Highest yield was obtained in the treatment 100% Crop load + 500ppm Ethephon, followed by 75% Crop load + 500ppm Ethephon. The treatment of 50% Crop load + 500ppm Ethephon resulted in maximum bunch weight, lowest percentage of uneven coloured berries, maximum TSS, minimum acidity and maximum TSS:acid ratio, maximum anthocyanin content, advanced maturity by 9 days and had maximum sensory rating. But, in this treatment, yield was significantly lower than in treatments where either 75% or 100% Crop load was retained. Thus, considering yield as well as quality parameters, the treatment 75% Crop load + 500ppm Ethephon was found to be the best.