Effect of AVG Application on Berry Set of 'Kyoho' Grape

AVG (2-aminoethoxyvinylglycine) applications to flower clusters of 'Kyoho' grapes before anthesis were investigated with respect to berry set, seeded berries and berry quality from 1994 to 1997. Flower clusters were dipped in AVG at 25, 50, 75, 100, or 300ppm 1 to 3 weeks before anthesis. At 50 to 300ppm AVG increased the rates of berry set and seeded berries. Higher concentrations applied before anthesis and a lower concentration applied toward the end of anthesis also were effective in increasing berry set and seeded berries. There were no significant differences in soluble solid content and titratable acidity between the control and AVG-treated berries, but the treated berries were somewhat heavier. ACC content in AVG-treated florets was lower : the ethylene evolution rate from florets correlated positively with ACC content. Water soluble growth inhibitors of pollen tube growth in the pistils decreased significantly after AVG treatment, compared to the untreated control. AVG treatment also increased the numbers of ovules per ovary and seeds per berry.