EFFECTS OF GA(4) AND GA(7) ON FLOWER BUD FORMATION AND RUSSET DEVELOPMENT ON APPLE

GA4+7 and GA4 substantially reduced russeting of 'Golden Delicious' apples in four years, GA4 was slightly more effective than GA4+7. The effect of gibberellins on flowering was variable and not always related to crop load the previous year. GA4 increased flowering in one experiment, had no influence in two experiments, and inhibited flowering in two experiments. GA7 either inhibited flowering or had no effect. In some instances GA4 partially reversed the inhibitory effect that GA7 had on flowering. Both GA4 and GA7 inhibited return bloom on Redspur 'Delicious', although GA7 inhibited flowering more severely. GA4 did not modify the effect of GA7 on flowering when the two gibberellins were applied in combination.