Search Results

You are looking at 1 - 4 of 4 items for

  • Author or Editor: R.D. Belding x
Clear All Modify Search

`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).

Free access

Apple sooty blotch (SB) is a disease complex caused by Gloeodes pomigina (Schw.) Colby, Leptodontidium sp. and other fungi. This study was undertaken to determine if G. pomigena and Leptodontidium sp. utilize some portion of the apple epicuticular wax as a carbon source for growth. Two isolates of G. pomigena and two of Leptodontidium sp. were used. Isolates were cultured on water agar coated with a thin layer of either nonacosane, ursolic acid, or complete apple wax and an uncoated control. Radial colony growth over a 30-day period was used to assess growth. Preliminary results suggest that G. pomigena differs from Leptodontidium sp. in carbon source preference. Gloeodes colonies were larger when ursolic acid and apple wax were used as a carbon source compared to nonacosane. Leptodontidium isolates grew best on apple wax. Also, growth was greater on nonacosane than ursolic acid. results from laboratory studies were compared to SB severity (percent surface area covered) in the orchard on cultivars of apples where the wax composition was determined. Although fungal genera were not detailed in the orchard, SB severity was positively correlated with the concentration of ursolic acid (r2=0.69) and nonacosane (r2=0.34).

Free access

Apple cuticular wax is the primary environmental interface between the fruit and pathogens or protectant chemicals. Analyses have shown quantitative and qualitative differences in wax of apple cultivars grown in various environments. Of the twelve major wax components, seven exhibited significant variations between Golden Delicious(GD) and Red Delicious(RD) cultivars in all three years. Of these seven components, two compounds occur in greater concentrations in RD than in GD cultivars, one which elutes soon after hexacosanol comprises 10 to 15 % of the RD wax composition verses less than 0.5 % in GD. The other compound comprised 5% of the RD wax verses 1-2% in GD. The other five compounds were found in greater concentrations in GD than RD cultivars. Tetracosanol and another early eluting unknown compound each make up 1 to 3.5 % of GD wax composition while appearing in only trace amounts in RD cultivars. Hexacosanol and a third later eluting unknown each constitute 2 % of GD while concentrations in RD were consistently 1 % or less. Ursolic acid, appears as two isomers, the first isomer constituted 12 to 16 % of GD wax and only 8 to 9 % of RD cultivars. Nonacosane and the major isomer of ursolic add constituted 50 to 70% of the total wax of each cultivar and were not significantly different.

Free access

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.

Full access