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

摘要

In 2002, a multi-site pear rootstock trial was established to evaluate 'd'Anjou' and 'Golden Russet Bosc' pear (Pyrus communis L.) performance on eight Pyrus rootstocks in the Pacific northwestern US states of Oregon and Washington. The plantings wereconducted 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 x Farmingdale selections (OHxF 87 and OHxF 40; US), 708-36 (East Mailing, UK), andPyrodwarf 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, OHxF 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 hadhigh YE. Cumulative tree yield and YE were consistently highest for OHxF 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) and708-36. For 'Golden Russet Bosc', cumulative tree yield was highest on OHxF 87, intermediate on OHxF 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 OHxF 87, butexhibited premature leaf reddening which may be indicative of pear decline. Based on the results of these trials, OHxF 87 was the best overall performing rootstock and appears well-suited for moderate-density winter pear plantings.