Influences of disbudding on yield and quality of 'Isabel' grapes

Abstract

Grapevine prebloom disbudding maintaining one sprout per node is done in Rio Grande do Sul State by many grape growers, mainly on labrusca cultivars. The convenience of utilizing this practice to grapevine cv. Isabel on overhead trellis was examined in five years studies. It were concluded that it induces decreasing of cluster weight and number, and total titratable acid. Otherwise, it induces increasing of total soluble solids and Brix/Acidit ratio. Mean cluster weight was not affected. Evaluations were made of reducing sugars content in the last two years of the trial; must pH, and trunk transversal section enlargement in the last year of the trial. No differences were found. The results show that disbudding restrained crop level but improved berry quality. These results indicate a probable cumulative effect, detected only after four sucessive growth seasons.