Influence of aminoethoxyvinylglycine and naphthalene acetic acid on fruit retention, quality, evolved ethylene, and respiration in apples

Effects of 1-aminoethoxyvinylglycine hydrochloride (AVG or Aviglycine HCl or ReTain) and α-naphthalene acetic acid (NAA) on fruit retention, fruit quality, eveloved ethylene, and respiration in ‘Rome Beauty’ and three ‘Delicious’ apple cultivars (Malus domestica Borkh.) were studied. The experimental trees were treated with either AVG, applied at 120 g a.i. per 935 L. ha-1 or NAA, applied at the rate of 10 ppm at 1870 L. ha-1. The AVG treatment was applied four weeks before anticipated harvest date while the NAA treatment was applied 7 days before harvest. In both ''Delicious'' and ''Rome'' apples, application of AVG maintained fruit retention and firmness but reduced starch hydrolysis, ethylene evolution, and respiration as compared to the NAA treatment. In the later harvests, fruit weights in NAA-treated trees were slightly higher than those treated with AVG. Fruit retention, maturity and quality differences between AVG and NAA treatments were more pronounced as the time past from the commercial harvest dates. Based on this study, application of AVG is more effective than NAA in preventing fruit drop and delaying fruit maturity and thus storage life of apples.