Study On Genetic Diversity Of Pear Germplasm Resources

There are abundant pear germplasm resources in Xinjiang.In this study,153 pear germplasms preserved in Xinjiang were used as test materials to analyze the variation of 74 botanical characters of pear germplasm resources and reveal their genetic diversity;through the study of fruit quality traits,we screened out the characteristics and germplasms which are more effective for production and breeding;combined with the genetic diversity of pear germplasm resources,the preliminary study on Pear Germplasm Resources in Xinjiang was carried out The main research results are as follows: 11.The variation of botanical characters of 153 pear germplasms including flower,leaf,bud,branch and fruit was analyzed.The statistical frequency of descriptive traits ranged from 0.00% to 99.35%,the coefficient of variation ranged from 8.03% to 69.01%,and the genetic diversity index ranged from 6.94 to7.25.The coefficient of variation of quantitative traits ranged from 10.53% to 40.45%,and the genetic diversity index ranged from 7.15 to 7.25;except that the number of flowers per order,the number of stamens,leaf circumference,fruit setting rate,single fruit weight,fruit stem diameter,fruit firmness and other seven traits did not belong to normal distribution,the remaining 12 traits were normal or partial normal distribution;the results of K-S test were consistent with the frequency distribution diagram.2.The correlation analysis of pear fruit characters showed that the single fruit weight was significantly positively correlated with fruit vertical and horizontal diameter,core vertical and horizontal diameter,fruit firmness and fruit setting rate;fruit hardness was significantly positively correlated with stone cells.Based on the fruit appearance,flavor,texture,yield and other traits,31 germplasm resources with smooth fruit and good coloring degree were selected;17 germplasm resources with rich juice,crisp texture,no astringent taste and rich flavor;7 germplasm resources with high fruit setting rate,large fruit shape,high sugar and low acid were selected.3.The 25 quantitative characters of pear germplasm resources were divided into 12 principal components by principal component analysis.The leaf traits were mainly concentrated in the first principal component,and the second to fifth principal components mainly reflected fruit traits.The 153 pear germplasm resources were classified into 7 groups at the threshold value of 12.5.The hybrid progenies ofKorla fragrant pear were mainly distributed in the first and fourth categories;Xinjiang pears and Western pears clustered into one group,showing a closer genetic relationship.