Effect of aminoethoxyvinylglycine and surfactants on preharvest drop, maturity and fruit quality of two processing peach cultivars

The effect of aminoethoxyvinylglycine (AVG), commercially available as ReTain, and three organo-silicone surfactants were evaluated in a series of four experiments over a 2-year period in two commercial peach orchards. Four rates of AVG (0, 66, 132, and 264 mg.L-1 AVG; all applied with 0.05% Sylgard 309) and three surfactants (0.05% Sylgard 309; 0.05% Regulaid; and 0.50% LI-700; all applied with 132 mg.L-1 AVG) were applied to 'Venture' and 'Babygold 7' peach trees 10 days before first harvest. Fruit were harvested according to commercial standard maturation criteria of background color, suture filling, and fruit size. Treatments were assessed in relation to fruit maturity, delay in harvest, fruit size and yield, fruit quality (flesh firmness and brix), as well as fruit quality following 2 weeks of cold storage. Based on sequential harvest data, the maturation of the AVG treated trees was delayed by about 3 to 4 days. Fruit from AVG treated trees were firmer at harvest and 2 weeks following cold storage at 2 degrees C. However, no additional increase in fruit size or yield was detected. In addition, the addition of a surfactant was not necessary for AVG to be efficacious for delaying maturity and enhancing firmness when applied at 132 mg.L-1 AVG. However, when the three surfactants were compared, Regulaid and Li 700 advanced color development in one experiment and Li-700 resulted in firmer fruit in another. Aminoethoxyvinylglycine applications to the clingstone cultivars 'Venture' and 'Babygold 7' can be used successfully to manage harvest activities by delaying the onset of picking and improving fruit firmness.