Percentage of fertility of gems and content of carbohydrates contained in roots, vine shoots and leaves from grape cultivar Itália

Abstract

Cultivar Itália is the main representative of the fine table grapes with seeds in the Vale do Submédio São Francisco, and, being introduced in a growing region, cultural management adjustments are necessary to make it more productive. Thus, the objective of this study was to evaluate the metabolism of carbohydrates contained in roots, shoots and leaves of cv. Itália, and their levels of influence on the fertility rates of gems in branches located in different regions of the primary arm of cv. Itália, grafted onto the rootstock IAC-313 (‘Tropical’). The experimental design was randomized block with three treatments and 15 replications, one plant per experimental unit. Roots, branches and leaves were collected before the yield prune, to determine the levels of carbohydrates. The analysis of bud fertility potential was held under a magnifying glass (magnification: 30 times), collecting three branches of the primary arm of each plant (basal, middle and apical), each containing 10 gems. After 27 days of the date of production pruning it was determined real fertility of gems, using the ratio: number of fertile buds by the total number of sprouted buds per plant. It was determined the levels of reducing sugars (RS) and total sugars (TS) and starch. It was found that the fertility of buds varies with the position of the branches in the plants, with a positive correlation between fertility and the potential gems of starch and total sugars, and that the expression of the fertility of buds on branches located in the basal position of the plant is higher.