Thirty-three years evaluating rootstocks for peach in the NC-140: what have we learned

摘要

The NC-140 project evaluated rootstocks for 40+ years. Coordinated peach rootstock testing began in 1984, and 6 trials were implemented, with 5 completed. The first trial included 16 states. Nine rootstocks included 4 industry standards (Prunus persica seedlings), a plum hybrid, own-rooted, and 3 Prunus hybrids. Peach seedling rootstocks had the best survival and yields except for 'GF677'. The 1994 trial was planted in 18 states/provinces with 18 rootstocks. High yielding rootstocks included the standards Lovell and Guardian~?. Yields were affected by rootstock and location. Ranking of rootstock performance did not change between years 5 and 8. Trials planted in 2001 and 2002 at 17 sites included 15 clonally propagated Prunus spp. and hybrid rootstocks and the peach seedlings 'Lovell', 'Bailey' and 'Guardian~?'. Both trials ended prematurely after 5 or 6 years due to virus concerns. These trials showed the potential of semi-dwarfing rootstocks in peach and the shortcomings of slow growth, poor anchorage, suckering, delayed incompatibility, small fruit size, and increased tree death in vegetative propagated rootstocks. The last completed trial in 2009 at 16 locations with 18 rootstocks included interspecific hybrids. Significant differences were observed among rootstocks and locations for most horticultural traits. Peach and peach hybrid rootstocks were the most vigorous and productive, while the Controller?series and plum rootstocks were the most yield efficient. In the southeastern US, 'Guardian~?' was the best rootstock due to its tolerance to bacterial canker. In the northeastern US, 'Controller? 7 and 8' showed superior performance to the traditional peach rootstocks. The hybrid 'Krymsk~? 86' had a superior performance on high pH soils. Overall, 53 rootstocks were evaluated. Peach seedling rootstocks were often better performers, but recent trials of non-seedling propagated cultivars have been promising, which has encouraged increased planting of clonal rootstocks for peach in North America.