EFFECT OF ROOTSTOCK ON GROWTH AND PRODUCTION OF 'FORELLE' PEAR: RIVERSIDE RESULTS

Abstract

European pears (Pyrus communis L.) are planted either on pear (Pyrus communis L.) or quince (Cydonia oblonga L.) rootstocks. Modern high density orchards require dwarfing rootstocks, but the popular South African rootstocks, BP1 and BP3, tend to be too vigorous. Pear rootstocks are reasonably precocious with good compatibility and anchorage, while various degrees of incompatibility exist between pear and quince. The growth and production of the pear cultivar, ‘Forelle’ was evaluated on a selection of pear and quince rootstocks at four sites. Results from the Riverside trial site are presented here. After one year, trees on BA29, QA and BP3 were the tallest, followed by trees on QC51 and BP1, with trees on OHxF97 being the smallest. After two years, trees on BA29 and BP3 were the tallest (~250 cm), followed by trees on QA, then QC51 and BP1, with the smallest trees being on OHxF97. After nine years, trees on BP1 and BP3 had the largest Trunk Cross-sectional Area (TCA) (~109 cm2), followed by trees on BA29 (97 cm2), then OHxF97, QA and QC51 (~79 cm2). Trees on BP3 produced significantly higher kg/tree than trees on QC51 and QA after four years. After nine years, trees on QA had significantly lower yield (18.6 kg/tree) than trees on the other rootstocks (~24.6 kg/tree). After nine years, trees on OHxF97 (0.32 kg/cm2 TCA) and QC51 (0.32 kg/cm2 TCA) were more efficient than trees on BA29 (0.27 kg/cm2 TCA), QA (0.24 kg/cm2 TCA), BP3 (0.23 kg/cm2 TCA) and BP1 (0.21 kg/cm2 TCA). Trees on OHxF97 (0.93 kg/cm2 TCA) and QC51 (0.92 kg/cm2 TCA) had higher cumulative yield efficiencies than trees on BP1 (0.62 kg/cm2 TCA) and BP3 (0.68 kg/cm2 TCA). Principal component analysis PCA indicated that yield efficiency, OHxF97 and QC51 were closely associated. With a risk of incompatibility, OHxF97 could be an alternative for BP1 and BP3, or otherwise, BA29 and QC51 should be considered.