Cumulative Yield, Tree Growth, and Yield Efficiency of 18 Asian Pear Cultivars

Abstract

Eighteen Asian pear cultivars on Pyrus betulaefolia rootstocks were planted in 1990 at Washington State University's Royal Slope Research Unit in central Washington State. Annual trunk diameters have been measured since planting, and annual harvest records have been kept since 1995. The six cultivars with the largest trees, ranked in decreasing order of trunk cross-sectional area, were `Daisui Li' (144 cm2), `Ishiiwase', `Huhoot Li', `Shin Li', `Shinsui', and `Yoinashi' (123 cm2). The six cultivars with the smallest trees were `Twentieth Century' (91 cm2), `Chojuro', `Shinseiki', `Shinko', `Yakumo', and `Tarusa Crimson' (38 cm2). `Tarusa Crimson' was significantly smaller than all other cultivars. The six highest-yielding cultivars, ranked in decreasing order of cumulative yield, were `Daisui Li' (183 kg/tree), `Shinseiki', `Shin Li', `Shinko', `Chojuro,' and `Olympic' (107 kg/tree). `Daisui Li' had significantly higher cumulative yield than all other cultivars. The six lowest-yielding cultivars were `Yoinashi' (71 kg/tree), `Huhoot Li', `Tarusa Crimson', `Yakumo', `Shinsui', and `Nangon Li' (19 kg/tree). The six highest-ranking cultivars for cumulative yield efficiency were `Shinseiki' (1.6 kg·cm–2), `Shinko', `Chojuro', `Daisui Li', `Tarusa Crimson', and `Olympic' (1.2 kg·cm–2). The six least-efficient cultivars were `Ishiiwase' (0.7 kg·cm–2), `Yakumo', `Yoinashi', `Huhoot Li', `Shinsui', and `Nangon Li' (0.2 kg·cm–2). `Daisui Li' and `Tarusa Crimson' had similar, relatively high, cumulative yield efficiencies, but for different reasons. `Daisui Li' produced high yields on large trees while `Tarusa Crimson' produced low yields on small trees. In contrast, the relatively high efficiencies of `Shinseiki', `Shinko' and `Chojuro' resulted from high yields produced on small trees.