Effect of good viticultural practices to reduce bunch compactness and berry size improvement in grapes cv. ‘crimson seedless

Abstract

The Grape variety, Crimson Seedless suffers from berry size and bunch compactness, which has bearing with its marketability and economic returns. The objective of this study was to evaluate various viticultural techniques, such as berry thinning (at 8-10 mm berry size), basal leaf removal, bunch covering and ethrel dip @ 500 ppm (at veraison stage) either in single or in different combinations to prevent bunch compactness and physiological loss in weight, and improve in berry size. The experiment was conducted during two consecutive seasons (2015-2017) in a vineyard located at ICAR-Indian Institute of Horticultural Research, Bengaluru, India. The prevalence of bunch compactness was evaluated considering the levels of compact ratio. The physical characteristics of bunches and the berries were also evaluated. Among the treatments, the highest mean bunch weight of 699.83 and 663.40 g, better bunch compactness ratio of 1.799 and 1.617, berry diameter of 18.31 and 19.03 mm, 50 berry weight of 230 and 274.40 g, and pulp to peel ratio of 9.246 and 9.243, and lower physiological loss in weight (PLW) of 24.82 and 15.49% during season-I and season-II, respectively were recorded under the combinations of berry thinning + 500 ppm ethrel dip + basal leaf removal. Berry thinning at 8-10 mm in diameter is efficient for reducing bunch compactness, as it resulted in a higher incidence of medium loose and lower incidence of very dense bunches with optimum PLW and higher berry size in Crimson Seedless grapes