Summary of the 2002 Pacific Northwest of USA Pear Rootstock Trials: Performance of 'd'Anjou' and 'Golden Russet Bosc' Pear on Eight PyrusRootstocks

Abstract

In 2002, a multi-site pear rootstock trial was established to evaluate 'd'Anjou' and 'Golden Russet Bosc' pear (Pyrus communisL.) performance on eight Pyrusrootstocks in the Pacific northwestern US states of Oregon and Washington. The plantings were conducted under the multi-state cooperative research project NC-140. Root-stock genotypes tested at all three sites included, Fox 11 (Bologna, Italy), two clonal Old Home × Farmingdale selections (OH×F 87 and OH×F 40; US), 708-36 (East Malling, UK), and Pyrodwarf and Pyro 2-33 (Geisenheim, Germany). In addition, Fox 16 (Bologna, Italy) was evaluated at the two WA sites, and Winter Nelis seedling was evaluated at the OR site. Summarized across all sites, OH×F 87 had the highest yields and yield efficiency (YE) and the largest average fruit size; Fox 11 and 708-36 produced the smallest trees; and Pyrodwarf produced significantly low cumulative yields of smaller fruit, possessed the lowest cumulative YE, and suckered profusely (counted in OR, and visually observed in WA). In general, 'd'Anjou' trees were larger than 'Golden Russet Bosc' for a given rootstock. For the inherently vigorous cultivar 'd'Anjou', 708-36 produced the smallest trees followed by the Fox selections, but none of these genotypes had high YE. Cumulative tree yield and YE were consistently highest for OH×F 87, the latter despite the relatively large tree size for this rootstock and cultivar combination. The lowest yields were observed for Pyrodwarf, Fox 11, Fox 16 (WA site only) and 708-36. For 'Golden Russet Bosc', cumulative tree yield was highest on OH×F 87, intermediate on OH×F 40 and Pyro 2-33, and significantly lower on Fox 11, Fox 16, 708-36, and Pyrodwarf. The rootstock 708-36, however, had similarly high YE as OH×F 87, but exhibited premature leaf reddening which may be indicative of pear decline. Based on the results of these trials, OH×F 87 was the best overall performing rootstock and appears well-suited for moderate-density winter pear plantings.