Abstract

Russet on apples, Malus domestica Borkh and other fruits results in lowered fruit quality and substantial economic losses to growers. In this study we investigated the effect of GA₃ and GA₄₊₇ on russeting. Russeting index of fruits were estimated at harvest. Apple trees, twenty years old Golden Delicious was sprayed with GA₃ at the concentrations10-20 mgL^-1 and GA₄₊₇ at 5-10 mgL^-1 during petal-fall at 7-10 days 3 time again. All applied concentration of GA₃ and GA₄₊₇ reduced russeting in Golden Delicious cultivar significantly and significant difference was found between GA₃ and GA₄₊₇ actions. The application of GA₃ or GA₄₊₇ caused fruits to shift to elongated shape due to increase of L/D ratio. The application of GA₃ or GA₄₊₇caused to increase the weight of Golden Delicious fruit significantly. When GA₃ or GA₄₊₇ were separately sprayed on Golden Delicious, it resulted in considerable decrease in russeting neither return bloom nor were fruit set influenced by treatment.

Key words: Apple russeting, Golden Delicious, gibberellins, GA₃, GA_4+7.