Pre-Harvest Treatments of Brassinosteroids on Improving Quality of Table Grapes (Vitis vinifera L.) Cv. Flame Seedless

Potential of brassinosteroids (BRs) as a preharvest treatment on hastening maturity and improving berry quality of table grape cv. Flame Seedless was investigated during two consecutive crop seasons of 2012 and 2013. The study was performed on 12-year old own rooted, Flame Seedless grapevines planted at 3 m x 3 m spacing trained on overhead system. Vines were treated with aqueous solutions of BRs (0.0, 0.1, 0.5 and 1.0 mg l -1 ) at 2 weeks after fruit set, and at colour break stage. At commercial maturity, clusters were harvested and physico chemical properties were analysed. Clusters treated with 1 mg l -1 BRs attained veraison 3 days earlier and significant increase in cluster and berry weight, length and breadth was observed when vines were sprayed with 0.5 and 1.0 mg l -1 BRs. All three concentrations of BRs increased berry firmness while the highest firmness was observed in berries received 0.5 mg l -1 BRs. BRs treatment significantly affected peel colour of grape berries in which, significantly lower luminosity ( L *) and b * value along with higher a * value was observed in berries treated with 1.0 mg l -1 BRs. Total Anthocyanin Content (TAC) and Total Phenol Content (TPC) were affected significantly in dose dependent manner, in which the highest dose (1.0 mg l -1 ) displayed the highest TAC and TPC. In conclusion, BRs at the dose of 1.0 mg l -1 could be an effective treatment to improve quality of grapes cv. Flame Seedless.