Effect of Ethephon, Brassinosteroid and Leaf Removal on Different Characteristics and Quality of Askari Grapes Sprayed with Dormax in Sisakht Area

In temperate and sub-temperate regions, short length of growing season is one of the main obstacles to successful commercial production of grapes. In a quest to overcome this concern, a factorial experiment in a randomized complete block design was conducted with three replications to evaluate the effect of application of dormax (1%) on early-blooming, followed by spraying ethephon (150 and 300 ppm), brassinosteroids (0.4 and 0.6 mg /L) and leaf removal at the onset of the leaf discoloration to examine the ripening time and quality characteristics of Askari grape (Vitis vinifera L. cv. Askari). Application of dormax had no significant increasing effect on carotenoid and decreasing effect on chlorophyll content of fruits. Leaf removal led to decreases in yield components such as cluster weight, number of berry in cluster and grape yield, and increases in the quality characteristics of grapes such as soluble solids, firmness, carotenoid content and color indices. Foliar-applied brassinosteroids (0.6 mg/L) + 1% dormax led to the best quantitative characteristics of grapes. The most desirable quality and color characteristics of fruits were observed with application of 1% dormax + 300 ppm ethephon.