Japan And South Korea Sand Pear Introduction, Screening And Diagnosis Of The Beginning Of Fruit Tree Nutrition Research

China is one of the original areas for the pear and It is a member of top three planting fruiters in our country. Both the planting acreage and the total output for the pear rank the first. But many defects exist in the pear industry such as unreasonable varieties structure, low yield per unit area, the shortage of high quality fruits, poor benefit and so on.With the aims of changing recent situation and of promoting a rationalization of the pear industry in Hunan Province, a passel of sandy pear varieties, including some originated from Japan and Korea, were introduced to "green dream" orchard in CSFU and to "Jindi" company of Yongzhou city, ten pear varieties ('Cuiguan', 'Qingxiang','Fengshui', 'Huanghua', 'Lubaoshi', 'Daguoshuijing', 'Hwangkumbae', 'Yuanhuang', 'Aidang' , 'xingao') are exerted on a introduction experiment and a research. In this experiment the main content is to observe their phonological periods, fruit qualities, growth characters, resistances to the diseases and productivity in Zhuzhou and in Yongzhou. With the help of multi-value theory, they are quantitatively evaluated on the basis of their performance at the following aspects: fruit qualities, growth characters, resistances to the diseases and productivity. As a result, Chinese pears perform better than Japanese pear and Korean pears and five varieties, 'Cuiguan', 'Qingxiang', 'Lubaoshi', 'Yuanhuang' and 'Aidang' have been screened because they are most surtful to the enviorment of Hunan Province in those ten varieties.In the processes of introducing and of screening, a nutrition diagnosis is executed on above-mentioned pear varieties in the leaves. In this diagnosis, it adopts 9 mineral elements: N, P, K, Ca, Mg, Fe, Mn, Cu, Zn. According to the diagnostic result, some conclusions are drawn:(1) For the content of nitrogen element, 'Yuanhuang' is low and the rest varieties are appropriate.(2) The phosphorus element content of 'Fengshui' is low and that of 'Daguoshuijing' is high. While the others are in an appropriate bound.(3)For the content of kalium element, four varieties, 'Huanghua', 'Hwangkumbae', 'Aidang' and 'Xingao' are in the appropriate bound and the rest varieties are low.(4) For the content of calcium element, merely two varieties, 'Cuiguan' and 'Aidang' are in the appropriate bound and the others are low.(5) The magnesium element contents of three varieties, 'Huanghua', 'Lubaoshi' and 'Aidang' are low. While those of the rest varieties are right.(6) For the content of Fe element, the most varieties are well-balanced and only 'Huanghua' is in the low bound.(7) The manganese element contents of 'Huanghua' is high and those of the restvarieties are appropriate.(8) The content of cuprum element is relatively complicated. Three varieties, 'Qingxiang', 'Lubaoshi' and 'Xingao' are in high bound, 'Daguoshuijing' is in low bound and the others are appropriate.(9) For the content of Zn element, the most varieties are well-balanced and only 'Cuiguan ' is in the high bound.