Evaluation of four potentially size-controlling pear rootstocks for commercial pear production in Canada.

摘要

The main rootstock for pear production in the province of Ontario, Canada is Bartlett seedling. A CanAdapt-funded project was established in 1998 to evaluate four alternative rootstocks using six different cultivars and selections. Clonal rootstock selections 'Old Home' x 'Farmingdale' (OH x F) 40, 69, 87, 97 were compared with Bartlett seedling rootstock in commercial orchards at five different sites with varying soils and climates. In 1999, nursery trees were similar in size but trees on Bartlett seedling rootstock had a 12-16% larger caliper size trunk than those on the OH x F selections. Trees were staked with 2 m steel posts and trained to a central leader system to ensure a dominant leader and early production. In 2006, trees on OH x F selections had larger trunk circumference (11-13%) than trees on Bartlett seedling rootstock. The increase in trunk circumference was 22-29% greater on the OH x F selections than on 'Bartlett' seedling rootstock. Accumulated yields to date are 31-75% greater on the OH x F selections than the 'Bartlett' seedling rootstock. Except for the first crop in the 5th leaf, the mean fruit size on 'Bartlett' seedling rootstock was smaller each year when compared to the OH x F selections. The four OH x F selections to date have out-performed the 'Bartlett' seedling rootstock for trunk circumference, yields and fruit size. Although the OH x F selections tested at grower sites do not appear to be semi-dwarfing under Ontario conditions, they offer many advantages over the standard 'Bartlett' seedling rootstock. This trial has also demonstrated the adaptation of new technology for pear production in Ontario.