Bud break and fruit set in selected grape genotypes from western Uganda

Abstract

Bud break and fruitfulness of a bud is a product of complex interaction of various factors leading to the formation of fruit bud. Fruit bud formation in grape takes place for the next year on current season’s growth, concurrent with fruit set (Chadha and Cheema, 1971). It is the consequence of transformation of vegetative primordium in to reproductive primordium in a bud. The transformation is carried out in three stages namely, anlagen formation, formation of inflorescence primordium and formation of flower (Srinivasan and Mullins. 1981). Among the three stages mentioned above, formation of inflorescence primordium is the most sensitive stage, though formation of anlagen itself considered to be the stage of initiation of inflorescence axis. Any imbalance among the factors responsible for formation of inflorescence primordium would make the anlagen to differentiate in to either tendril or shoot. Bud fruitfulness varies with the inherent capacity of the variety. Under given environmental conditions, the number of fruiting primordial which develop in a bud are influenced by cultivar. Different grape cultivars vary widely in their ability to initiate flowers. Hence, studies on varietals variation with regard to bud break and fruit set is of paramount significance. The knowledge that the fruit buds in grape differentiate and develop early in the previous season has led to the studies on the possibilities to forecast the fruitfulness of the buds in the ensuing season for meaningful pruning recommendation on the basis of an examination of dormant buds

Key words: Fruit bud differentiation, pruning, inflorescence primordium, and bud fruitfulness