Asian Pear Cultivar Evaluation in Central Washington State: Tree Size, Cumulative Yield, Yield Efficiency, Bloom and Fruit Maturity Dates

Abstract

Twenty-five Asian pear ( Pyrus bretschneideriRehd., P. serotinaRehd. and P. ussuriensisMaxim.) cultivars plus ‘Bartlett’ ( P. communisL.) were planted in March of 1990, 1991 or 1992 at Washington State University's Royal Slope Research Unit in central Washington State. Trunk diameters were measured annually, and annual yield data were recorded beginning with the first commercial harvest in 1995.

Among the trees planted in 1990 on P. betulaefoliarootstocks, the six cultivars with the largest trees, ranked in decreasing (but not significantly different) order of trunk cross-sectional area, were ‘Daisui Li’ (144 cm ²), ‘Ishiiwase,’ ‘Huhoot Li,’ ‘Shin Li,’ ‘Shinsui’ and ‘Yoinashi’ (123 cm ²). ‘Tarusa Crimson’ was smaller than all other cultivars. ‘Daisui Li’ had the highest cumulative yield. The six lowest-yielding cultivars, ranked in descending (but not significantly different) order, were ‘Yoinashi’ (71 kg tree ^-1), ‘Huhoot Li,’ ‘Tarusa Crimson,’ ‘Yakumo,’ ‘Shinsui’ and ‘Nangon Li’ (19 kg tree ^-1). The six highest-ranking cultivars for cumulative yield efficiency (cumulative yield per unit trunk cross-sectional area) 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).

Among trees planted in 1991, ‘Seigyoku’ and ‘Niitaka’ produced larger trees than ‘Singo.’ There were no cumulative yield or cumulative yield efficiency differences among these three cultivars.

Nangon Li’ and ‘Daisui Li’ were among the earliest cultivars to reach full bloom; ‘Kosui’ and ‘Bartlett’ were among the latest. ‘Ichiban Nashi’ fruit were generally the first to mature, with ‘Seuri,’ ‘Tse Li’/Winter Nelis, ‘Ya Li’ and ‘Tarusa Crimson’ tending to be latest.