Two-year-old ‘Redhaven’ peach (Prunus persica (L.) Batsch) trees on 7 different peach seedling rootstocks growing on short-life and on non-short-life sites were examined for cold hardiness of trunks using trunk cambial browning (TCB), and cold hardiness of twigs using tests for electrolytic conductivity (EC), triphenyl tetrazolium chloride (TTC), and ninhydrin-reactive compounds (NRC). It was found that Lovell, Halford, and NA 8 rootstocks invariably imparted more cold hardiness to ‘Redhaven’ budded onto them than other rootstocks tested, whereas maximum cold injury was sustained by trees on NRL 4 rootstock. Tree mortality was higher and cold injury was more severe on the short-life site than on the non-short-life site.
Fifty-nine available combinations of 16 peach [Prunus persica (L.) Batsch] seedling rootstocks and four cultivars were evaluated for survival, growth, productivity, and peach tree short life (PTSL) performance of scions for 10 years (1975–1984). Rootstock influenced tree survival, cold and bacterial canker damages, root suckering, bloom date, degree of budbreak, and fruit yield. However, rootstock had little effect on bud density, fruit maturity and size, and time of autumn defoliation, and no influence on trunk circumference and bark gummosis. Cultivars differed in all characteristics except tree survival and canker damage. Tree survival was negatively correlated with budbreak, bloom date, cambial browning, Pseudomonas canker, suckering, and defoliation. Lovell rootstock had the best overall PTSL-related performance, while Siberian C had the worst. ‘Derby’ was the most desirable and ‘Hamlet’ the least of the four cultivars evaluated.
Trunk bark thickness of 6 peach clones was significantly affected by seedling root-stocks of peach (Prunus persica (L.) Batsch). Of the 7 rootstocks tested, Siberian C invariably induced the thickest bark in the scion while Lovell and Halford induced the thinnest scion bark. However, Siberian C grown as unbudded seedling trees did not produce thicker bark than the other rootstocks, similarly grown. The effect was not site- or cultivar-dependent.
The reliability, capability to predict survival, and convenience of 5 cold hardiness tests — triphenyl tetrazolium chloride reduction (TTC), electrolytic conductance (EC), ninhydrin-reactive compounds (NRC), trunk cambial browning (TCB), and bacterial canker development (BCD) — were evaluated using previous season's twigs of ‘Redhaven’ peach (Prunus persica (L.) Batsch) during the 1976-77 dormancy season. TTC, NRC, and EC were all significantly correlated with TCB as well as percent tree survival (PTS) in the field, and thus proved to be quantitative, reliable and capable of predicting survival at a later date. No statistical correlation was found between BCD and other hardiness tests.
Visual rating scales were developed for evaluating tissue injury in peach trees [Prunus persica (L.) Batsch] in the orchard due to cold/winter temperatures and bacterial canker (Pseudomonas syringae van Hall) development. The numerical ratings on a scale of 1 to 9 separately describe key stages of damage and its severity due to cold and bacterial canker and are portrayed pictorially for clarity. Accurate estimation of tree status at very early stages of injury and good correlation with ultimate tree survival have been possible through the use of these rating scales. This information has been incoporated in the data collection for a regional research project dealing with the development and evaluation of rootstocks for peach in the southern United States and also is under consideration for use in another regional project involving peach in addition to apple, pear, and cherry.
Effects of 8 peach seedling rootstocks on tree growth, survival, and fruit yield of ‘Redhaven’ and ‘Loring’ peach scion cultivars were tested in Alabama, Arkansas, Georgia, North Carolina, and South Carolina. Lovell seedling rootstock was a standard for comparison. Six years of data indicated that Siberian C was not an acceptable rootstock because tree survival and fruit yield were low. Halford was equivalent to Lovell for tree growth, fruit yield, and survival. Fruit size was unaffected by rootstock. Nemaguard and 2 North Carolina selections were resistant to root-knot nematodes (Meloidogyne spp.) but they were not resistant to ring nematodes [Criconemella xenoplax (Raski) Luc and Raski]. Soil fumigation improved tree survival in nematode-infested soil.