| Castanea henryi is a unique fruit tree species of Fagaceae in China.At present,it is widely planted in Fujian Province and other regions.It has become the main source of income for local farmers.Through continuous natural selection and artificial cultivation,a number of varieties and local varieties have been formed.There is an important significance of protection and breeding utilization in C.henryi gene resources that studying the genetic variation of varieties and local varieties.In this study,the genetic variation of C.henryi cultivation population was analyzed by SSR molecular marker technology.The variation of important economic traits and chestnut blight resistance was analyzed,and the selection of superior trees and the evaluation of some characteristic germplasm resources were conducted.It provided a basis for the breeding of new varieties with high resistance,yield and quality.The main results are as:1.The determination and variation analysis of important traits of 30 individuals in ‘Youzhen’ were carried out for two consecutive years.The coefficient of variation ranged from 8.46% to 59.41%,and the average coefficient of variation was 23.06%.Analysis of variance showed that there were highly significant differences in fruit bract length,fruit bract width,fruit bract thickness,thorn length,leaf width,leaf area,leaf vein number,petiole length,soluble sugar,starch,sucrose,reducing sugar,soluble protein and disease infection rate(p≤0.01).There were significant differences in fruit bract height,total bract weight,fruit weight and leaf length(p≤0.05).Correlation analysis showed that the infection rate were highly significantly negatively correlated with soluble sugar,sucrose and reducing sugar(p≤0.01).Taking fruit yield and nutrient content as breeding objectives,5 plus trees were selected(YZ7,YZ28,YZ17,YZ21,YZ3),chestnut blight resistance as the breeding goal,two superior trees were selected(YZ5 and YZ30).2.The determination and variation analysis of important traits of 30 plants in ‘Chushuhong’ were carried out for two consecutive years.The coefficient of variation ranged from 8.35% to 110.64%,and the average coefficient of variation was 31.36%.Variance analysis showed that there were highly significant differences in bract weight,fruit height,leaf length,leaf width,leaf length/leaf width,starch,sucrose and disease infection(p≤ 0.01),and there was a significant differences in petiole length(p≤0.05).Correlation analysis showed that the infection rate were highly significantly negatively correlated with sucrose(p≤0.01).Taking fruit yield and nutrient content as breeding objectives,five superior trees were selected(CSH30,CSH23,CSH5,CSH16,CSH29).Taking the resistance of chestnut blight as the breeding goal,five superior trees were selected(CSH6,CSH11,CSH25,CSH29 and CSH30).3.The determination and variation analysis of important traits of 30 plants in ‘Tiezhui’ were carried out for two consecutive years.The coefficient of variation ranged from 9.38% to 37.28%,and the average coefficient of variation was 21.46%.Analysis of variance showed that there were highly significant differences in bract length,bract width,bract height,thorn length,bract weight,fruit weight,fruit width,fruit height,leaf length,leaf width,leaf length/leaf width,leaf area,leaf vein number,petiole length,sucrose,reducing sugar and disease infection(p≤0.01).There were significant differences in bract thickness,fruit length and starch(p≤0.05).Correlation analysis showed that the infection rate was significantly negatively correlated with soluble sugar and soluble protein(p≤0.05).Taking fruit yield and nutrient content as breeding objectives,5 plus trees were selected(TZ8,TZ3,TZ17,TZ30,TZ18).chestnut blight resistance as the breeding goal,three superior trees were selected(TZ3,TZ19 and TZ24).4.Six pairs of EST-SSR were used to analyze the genetic variation of ’ Youzhen ’,’ Chushuhong ’ and ’ Tiezhu ’ Castanea henryi.A total of 18 bands were amplified from 30 of ‘Youzhen’,15 bands were polymorphic.The genetic similarity coefficient between individuals ranged from 0.500 to 1,with an average of 0.842.A total of 20 bands were amplified from30 individuals of ‘Chushuhong’,and there were 19 polymorphic bands.The genetic similarity coefficient ranged from 0.333 to 1,with an average of 0.834.A total of 40 bands were amplified from 30 individuals of‘Tiezhui’,all of which were polymorphic bands.The genetic similarity coefficient ranged from 0.000 to 0.947,with an average of 0.391.5.The important traits and variation analysis of 26 varieties and local varieties were determined.The variation coefficient of 26 varieties and local ranged from 6.75% to 51.95%,with an average of 24.90%.Variance analysis showed that there were highly significant differences in bract length,bract width,bract thickness,thorn length,bract weight,fruit weight,fruit length,fruit width,fruit height,leaf length,leaf width,leaf length/leaf width,leaf area,sucrose and reducing sugar(p≤0.01),and there were significant differences in leaf vein number and petiole length(p≤0.05).Correlation analysis showed that the positive correlation coefficient between soluble sugar and sucrose was the highest,and the negative correlation coefficient between sucrose and soluble protein was the highest.KS26(Chushuhong),KS25(Hezhen)and KS23(Xiaojianzui)ranked the top three in terms of fruit yield and nutrient content.6.The growth traits and chestnut blight resistance of 50 individuals in C.henryi population from secondary forest were determined and analyzed.The coefficient of variation ranged from 18.15% to 43.23%,and the average coefficient of variation was 27.90%.Variance analysis showed that there were highly significant differences in leaf length,leaf width,leaf length/leaf width,leaf area,leaf vein number and disease infection(p≤0.01).Correlation analysis showed that the infection rate was positively correlated with leaf length,leaf length/leaf width and petiole length,and negatively correlated with tree height,ground diameter,eastwest crown width,north-south crown width,leaf width,leaf area and leaf vein number.Taking the resistance of chestnut blight as the breeding goal,five superior trees were selected(W3,W16,W19,W32 and W15). |
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