The Research On Walnut Resources And Selective Breeding In The Southwest Of Hunan Province

Walnut is a good economic tree species as one of the world famous nuts and woody oil crops with excellent nutritional value,combining economic,ecological and social benefits.This study represented by Longshan county in the south of Xiangxi autonomous prefecture walnut germplasm resources were investigated.Primarily 25 dominant individual plants of walnuts were used to measure the nuts including the phenotypic and economic traits,oil fatty acid components,physicochemical properties as well as the nucleoli mineral elements,respectively.The initial selection of 25 dominant individual plants of walnuts put the main phenotypic traits of nuts,economic characters,fatty acid composition and content as the nut quality evaluation indexes,by using the method of principal component analysis for nuts quality comprehensive evaluation.Correlation analysis and principal component analysis of nine mineral elements from kernel and determining the amount of each mineral elements are instructive to select appropriate planted in practical production,fertilizer,etc.The main conclusions are as follows:(1)The average data from 25 walnuts nuts display the diameter(34.31mm),the lateral diameter(31.08mm),the longitudinal diameter(34.39mm),shell thickness(1.76 mm),kernel rate(50.58%),oil yield(67.69%).Most of the nuts for easy to peel and good taste conform with the requirement of consumers.(2)The average contents of five kinds of fatty acids were detected from high to low:linoleic acid>oleic acid>linolenic acid>palmitic acid>stearic acid.The content of palmitic acid,stearic acid and linoleic acid are relatively stable compare with oleic acid and linolenic acid.Walnut oil is rich in unsaturated fatty acids and polyunsaturated fatty acids are in the majority.The oil physicochemical properties from different walnuts have little difference.(3)Kernel weight,three diameter,kernel rate,oil yield,kernel plumpness,kernel filling rate,kernel color and linoleic acid are important indexes to evaluate the walnut quality.The nut quality optimal walnuts are No.2(Baiyangdaping 1),No.17(Jiashijieshang 1),No.10(Dianfang lianxing 3),No.13(Guitangwangdao 1)and No.15(Huatangjianglai 1);the worst quality group include No.4(Ciyanshuxi 4),No.5(Daan dawang 1)and No.7(Daan taozi 1).Baiyangdaping 1,Jiashijieshang 1,Dianfang lianxing 3,Guitangwangdao 1 and Huatangjianglai 1 can be used as dominant individual plant candidates to combined with the comprehensive evaluation on the indexes of yield and resistance for selective breeding.These result provide a reference for dominant individual walnut selection and breeding.(4)The dominant individual plant contained elements average from high to low in turn:K(7121.340μg/g)>P(3582.477μg/g)>Mg(1636.486pg/g)>Ca(436.508μg/g)>Na(147.004μg/g)>Mn(32.454μg/g)>Zn(23.019μg/g)>Cu(13.482μg/g)>Fe(12.479μg/g).The coefficient of variation have a significant difference in different elements from each variety.The highest is Ca element and the lowest is Mg element.(5)No correlation between most elements,Na element content may be related to Ca,Mn and Cu content.The amount of mineral elements cannot represent nuts quality.