Studies in adaptation of new Japanese pear cultivars to major pear growing area

研究了作者培育的日本梨新品种秋白、醉树和新珠在梨主产区的适应性，结果表明：这3个品种在杜梨和红梨砧木上，树体生长和果实品质不受砧木种类的影响。测定了不同品种果实的贮藏潜力和乙烯释放量。‘神珠’表现出较高的乙烯释放量和较低的贮藏潜力。而‘秋葵’和‘醉薯’乙烯释放量低，贮藏潜力高。‘秋梨’果实淀粉含量一直保持较高水平，到成熟时蔗糖含量最高。这3个品种在日本梨产区福岛、千叶、长野和鸟取均表现出优良的果实品质，但在这些地区的“秋叶原”果实中发现了水心病，GA处理提高了“秋叶原”果实的水心病发病率，并通过夏季运行加以预防。秋海棠夏季修剪新梢对果实品质无影响，夏跑制度是防治水心病的实用措施之一。其减轻症状的机理可能是通过抑制果实糖负荷过重而实现的。

Adaptability to the major pear growing area of the new Japanese pear cultivars 'Akibae', 'Zuishu' and 'Shinzyu' which were breaded by the authors were investigated.Tree growth and fruit quality was not affected by the rootstocks species when these three cultivars were grown on P. betulaefolia and P. callerayana rootstocks. The storage potential and ethylene evolution of fruit of the cultivars were determined. 'Shinzyu' showed higher ethylene evolution and low storage potential. In contrast 'Akibae' and 'Zuishu' had high storage potential due to their low ethylene evolution.'Akibae' fruit kept high starch content until just before maturation, then it showed the highest sucrose contents than the other Japanese pear cultivars when fruit reached the mature stage. These three cultivars showed excellent fruit quality on the Fukushima, Chiba, Nagano and Tottori where the pear growing area in Japan, however, Watercore disease was detected in 'Akibae' fruit on these area.Watercore incidence in 'Akibae' fruit was increased by GA treatment and prevented by summer running. The fruit quality of 'Akibae' did not affected when new shoot was pruned in summer, thus summer running system seemed to be one of the practical method to prevent the watercore incidence. The mechanism of the decrease of the symptom may occurred by the inhibition of over load of sugar to the fruits.