Six-year performance of 14 Prunus rootstocks at 11 sites in the 2001 NC-140 peach trial

Fourteen Prunus rootstock cultivars and selections budded with either ‘Redtop’, ‘Redhaven’ or ‘Cresthaven’ peach [ Prunus persica (L.) Batsch] were planted at 11 locations in North America in 2001 in a randomized block design with a tree spacing of 5 by 6 m and 8 replicates. This test planting was an NC-140 Cooperative Regional Rootstock Project (www.nc140.org). There were 14 rootstocks in total, which included three peach seedling rootstocks: Lovell, Bailey, and Guardian ® ‘BY520-9’ [selection SC-17]. Clonal rootstocks included the peach × almond hybrids BH-4 and SLAP (Cornerstone); peach × plum hybrids K146-43 (Controller 5), K146-44, and P30- 135 (Controller 9); interspecific plum hybrids Hiawatha, Jaspi and Julior; interspecific Prunus hybrids Cadaman ® and VVA-1 (Krymsk ® 1); and Prunus pumila L. selection Pumiselect ® . Final tree size was largest in California, Georgia, Maryland, and South Carolina. BH-4, SLAP, SC-17, Lovell, and Cadaman ® were the most vigorous rootstocks. Jaspi, K146-43, K146-44 and VVA-1 were the least vigorous, having trunk cross-sectional areas 20-50% of Lovell-rooted trees. No rootstock had a significantly higher survival rate than Lovell at all locations, but Bailey, K146-44, and P30-135 had good survival at all test sites. Julior and Jaspi consistently produced root suckers. Pumiselect ® had anchorage problems at several locations. Cumulative fruit yields were highest on the peach seedling, peach × almond, and Cadaman ® rootstocks. Lowest cumulative yields were from the small trees on Jaspi, VVA-1 and K146-44 rootstocks. Fruit weight did not differ much among rootstocks though cultivars on Pumiselect ® and K146-43 often had smaller fruit. Cumulative yield efficiency was not consistently related to tree size. Rootstocks influenced dates of bloom and harvest, but not in a consistent manner across locations/cultivars