Nine-Year Rootstock Performance of the NC-140 ʽRedhavenʼ Peach Trial Across 13 States

Abstract

Prunusrootstocks (13 to 18) budded with ‘Redhaven’ peach [ Prunus persica(L.) Batsch] were planted at 16 locations in North America in 2009 and evaluated for nine years at all but 3 sites. Significant differences among rootstocks and sites were found for survival, root suckers, tree growth, flowering date, fruit maturity date, fruit size, cumulative yield, and yield efficiency at the remaining 13 locations in 12 states in 2017. Survival was highest for the four peach seedling rootstocks. In contrast, survival of non-peach species and hybrid rootstocks was poor to fair in Missouri (cold injury, wet feet conditions), Illinois (unknown), and in Alabama, Georgia, North Carolina, and South Carolina due to bacterial canker disease ( Pseudomonas syringae). Rootstocks ‘Krymsk® 1’, ‘Krymsk® 86’, ‘Empyrean® 2’, ‘Empyrean® 3’, ‘Controller™ 5’, ‘Imperial California’, and ‘Rootpac® R’ were the most susceptible to tree death from bacterial canker in the four southeastern states. ‘Fortuna’ exhibited incompatibility symptoms and had very high mortality at most locations. Overall, ‘Imperial California’ and ‘Fortuna’ had the lowest survival. Rootstock suckering was excessive on Prunus americanaseedlings, with lesser suckering noted on ‘Rootpac® R’, ‘Krymsk® 1’, ‘Empyrean® 2’, ‘Empyrean ® 3’ and Guardian®. Largest trees were on Prunushybrids ‘Viking’, ‘Atlas’, ‘Bright’s Hybrid #5’ and ‘Krymsk® 86’, and peach seedlings Guardian® and Lovell. Fruit size varied with location and crop load (i.e., some rootstocks had few fruit). ‘Atlas’, ‘Bright’s Hybrid #5’ and Guardian® produced the largest fruit across locations though all but three rootstocks produced adequate or excellent size. ‘Controller™ 7’ and ‘Imperial California’ produced slightly smaller fruit on average while ‘Fortuna’ had the smallest fruit across all sites. Fruit weight varied significantly among locations. South Carolina and Utah grew the largest fruit; whereas New York and Georgia recorded the smallest fruit. Cumulative yields were highest for the peach seedling rootstocks Guardian®, Lovell, KV010127, and hybrids ‘Atlas’ and ‘Viking’. The lowest yields were from trees on plum hybrids and plum species. Cumulative yield efficiency after 9 years was highest on clonal peach rootstocks ‘Controller ™ 7’ and ‘Controller™ 8’ and the plums ‘Krymsk® 1’ and P. americana. These data suggest that there was no demonstrated advantage to increase yield/ha by using clonal interspecific Prunus hybrids for peach production under current cultural practices, but the potential to increase productivity per ha exists with higher planting densities. Moreover, on high pH soils in Colorado and Utah, peach seedlings were not the superior rootstocks for production, so continuing evaluation of non-peach rootstocks is warranted.