Fall and summer pruning to control vigor in d'Anjou pear

Authors: MUSACCHI, STEFANO - Washington State University; SERRA, SARA - Washington State University; Mattheis, James

Submitted to: International Symposium on Integrating Canopy, Rootstock and Environmental
Publication Type: Abstract Only
Publication Acceptance Date: 3/20/2016
Publication Date: 9/6/2016
Citation: Musacchi, S., Serra, S., Mattheis, J.P. 2016. Fall and summer pruning to control vigor in d'Anjou pear. International Symposium on Integrating Canopy, Rootstock and Environmental. p. 30.

Interpretive Summary:

Technical Abstract: Controlling vigor in d’Anjou trees is an ongoing challenge in Washington pear orchards. Vigor depends on: nitrogen fertilization, cultivar, rootstock, and pruning/training system. Cultivar d’Anjou is inherently more vigorous than other cultivars, like Bartlett, which induces a more manageable tree. Larger trees are less prone to mechanization, are more labor-intensive to pick, and discourage pickers from working in pear orchards. The goal of this trial is to alter pruning management (fall+ summer pruning compared with the current standard winter pruning) to reduce tree vigor while maintaining yield and quality. The trial was carried out in a d’Anjou orchard trained at central leader and planted in 1998 on three different rootstocks: Old Home x Farmingdale (OHF) 97, 69, and 87, the first is a vigorous rootstock while the other two semi-vigorous. Fruit from harvest 2014 were analysed immediately after harvest and pulled out after two and four months of air storage at -1°C; fruit quality and maturity were assessed keeping fruit divided in IAD classes. Skin color parameters (L, a, b), red blush overcolor percentage, weight, firmness, soluble solids content (SSC), exogenous ethylene concentration, cork incidence, acidity, and pH were assessed at each pull out after 7 days of ripening. Pear flesh samples were analyzed for calcium, nitrogen and other nutrients content. Differences in amount of pruned wood were found among fall, summer, and winter pruning times. More material per tree was removed during fall pruning 2015 in comparison to winter and summer pruning. In March 2015, flower buds per m3 were counted and values revealed a tendency of fall+summer pruned trees having a higher number of flower buds/m3 than winter pruned ones. Yield 2015 was higher on winter pruned trees with bigger fruit than fall+summer pruned ones. Average fruit weight of winter pruning treatment was higher than the fall+summer one.