The Effect of Potassium Gibberellate on Flower Bud Development in the Redskin Peach1

Abstract

Applications of potassium gibberellate (KGA) were made to ‘Redskin’ peach trees at various times after bud differentiation. KGA applied before leaf fall caused flower bud mortality and retarded bud development, depending on timing and concentration. Response peaks for each of these effects occurred at different stages in the development of flower buds. The KGA-induced retardation of floral development reduced the damage caused by frost during the bloom period. In contrast to the delay in bloom obtained when KGA was applied before leaf fall, flower bud development was accelerated when KGA was applied after a substantial part of the chilling requirement had been satisfied. The cold hardiness of the dormant flower buds was not greatly affected by KGA.

Peach Flowering Response as Related to Time of Gibberellin Application1

“…Retardation of bloom was equated with increased bud survival. This relationship has also been found in previous work (12).…”

“…1A). This response peak occurred well after flower initiation, and is identical to that observed by Stembridge and LaRue (12). Application of GA3 early in the summer advanced floral development the following spring, and increased the injury from frost during the bloom period (Fig.…”

“…The % flowers open on a given date is a good indication of treatment effects on bloom delay (3,12), but such data were not obtainable because frost killed many buds before bloom. Sub-freezing temperatures occurred on 4 nights shortly before and during bloom.…”

Siberian C Rootstock Delays Bloom of Peach 1

“…Haskells No. 45' (1), 'Chasselas' (1), 'Concord' (19), 'Catawba' (16), 'Emperor' (8), 'Muscat Hamburg' (2 2 ),'Tokay' (2), 'Red Muscadel' (12), and 'Liatiko' (3). Mutations from seedless to seeded have been recorded in 'Panariti' (14), and 'Sultanina' (5).…”

“…Other methods of delaying bloom of peach also delay development of cold hardiness in the fall. These methods include applying nitrogen fertilizer to the soil in the fall (9), applying gibberellic acid in later summer (3,12), and summer defoliation, which causes regrowth late into the fall (4). While these methods work in mild climates, they are ineffective or hazardous in areas with fall frosts.…”