`Biscoe' and `Encore' peach [Prunus persica (L.) Batsch] trees were treated in two years with AVG at 7, 14, or 21 days before first harvest (DBFH) or as a nontreated control (NTC). Fruit were harvested every 2 to 3 days based on observed initial yielding of fruit flesh and ground color. Fruit were further evaluated for maturity and quality based on the production of ethylene, ground color, diameter, flesh firmness, soluble sugars, and woolliness. Evaluations occurred 1 day after harvest and after 14 and 28 days in cold storage. AVG applications delayed early harvests of `Biscoe', but `Encore' harvests were not affected. Across all preharvest treatment timings, AVG reduced ethylene production by 64%. Ethylene production and fruit softening were most inhibited for fruit treated with AVG 7 DBFH. In this study, fruit treated with AVG demonstrated a significant negative correlation between fruit ethylene production and firmness. Average flesh firmness of fruit from AVG treatments were 11.8 Newtons greater than NTC fruit. Fruit treated 21 or 14 DBFH exhibited greener ground color than NTC fruit or fruit treated 7 DBFH. The NTC fruit had the highest ground color values, fruit treated 7 DBFH were intermediate, and fruit treated 21 or 14 DBFH had the lowest values for ground color. AVG has potential use as a management tool for controlling the timing of harvest and for allowing fruit to ripen more slowly and to hang longer on the tree, thus improving fruit size. In addition, AVG assists in maintaining the postharvest flesh firmness required to withstand handling during marketing. Chemical name used: aminoethoxyvinylglycine (AVG).
Robert D. Belding and Gail R.W. Lokaj
Robert D. Belding, Bradley A. Majek, Gail R.W. Lokaj, Jeffrey Hammerstedt, and Albert O. Ayeni
Peach (Prunus persica) trees were established and grown from 1996 to 1999 at the Rutgers Agricultural Research and Extension Center, Bridgeton, N.J., to compare performance under four methods of orchard floor preparation: flat no-till, flat cultivated, mound unmulched, and mound mulched orchard floors. The experimental site was flat and the soil was a well-drained Aura gravelly sandy loam (61% sand, 31% silt, 8% clay) with a pH of 6.5, cation exchange capacity 5.7, and organic matter content of 2.0%. Soil moisture holding and gas exchange capacity determine the efficacy of mounding in peach orchards. Under these conditions, the method of orchard floor preparation had no effect on peach tree trunk cross sectional area (TCSA), fruit number per tree, fruit size, and yield. Thus, without irrigation, there was no advantage to the early performance of peach trees associated with orchard floor mounding on Aura gravelly sandy loam when situated on a flat terrain.