Abstract
An experiment was conducted to extend the timing of GA3 application at flowering stage for enlargement of seedless berries induced by streptomycin in grape ‘Fujiminori’. GA3 25ppm or 2.5ppm was applied to flower clusters at different dates during the flowering stage, followed by an application of GA3 25ppm or a combination of GA3 (50ppm or 100ppm) and 1-(2-chloro-4-pyridyl)-3-phenylurea (10ppm) at about 10 days after flowering. All treatments resulted in nearly 100% seedless and enlarged berries. However, the earliest and latest application of GA3 resulted in cases of bent rachis or a significant reduction in Brix of the flesh. No such damages were detected on the berries and clusters when GA3 was applied in the 3 day interval before and after full-bloom. The extended timing of GA3 application may allow growers to regulate and disperse their peak labor requirements.
