Preharvest Watersprout Removal Influences Canopy Light Relations, Fruit Quality, and Flower Bud Formation of `Redskin' Peach Trees

Abstract

Three separate blocks of mature, nonirrigated trees of `Redskin' peach [Prunus persica (L.) Batsch] on `Lovell' rootstock, all uniformly dormant-pruned to an open center, were summer pruned 43, 31, and 21 days before harvest (DBH) in 1988, 1989, and 1990, respectively, and compared to unpruned controls in respect to light penetration and fruit characteristics. Summer pruning consisted of watersprout removal (WSR), selectively including all shoots more upright than 45° on scaffolds from the crotch to the top of the tree. WSR increased photosynthetic photon flux density (PPFD) in the center of the fruiting zone of the canopy to four times the level measured in unpruned trees, but only to an average of 16% of above-canopy PPFD. The greatest effect of WSR on PPFD occurred in the center of the tree, increasing light levels from <10% full sun before WSR to 90% full sun following WSR. WSR resulted in higher PPFD in the center of the tree for the remainder of the season. Fruit ground color and red pigmentation were not affected by WSR. WSR increased the percentage of fruit that exceeded 62 mm in diameter and decreased the percentage of fruit < 55 mm in diameter in 1988 and 1990. In 2 of the 3 years, WSR increased flower count per cm shoot length in the fruiting zone of the canopy.