Studies on the sultana vine. II. The course of bud burst.

Abstract

Sultana vines were examined during bud burst for four seasons, and the date on which each shoot arose was noted. The shoots were later classified as fruitful, barren, or defective. The vines were pruned uniformly in the first season, and two pruning treatments were compared in the other three seasons. In all cases the mean time of bursting a t each bud position was progressively later from the distal to the proximal end of the cane, the number of newly burst buds found at each examination was related to preceding temperatures, and the percentage of fruitful shoots among new shoots found at each examination decreased from the beginning to the end of bud burst. Accessory shoots arising as a result of the death of primary shoots or buds were very rarely fruitful. The results are considered in relation to the discrepancy sometimes found between the percentage of fruitful buds and the percentage of fruitful shoots.