Analysis Of Genetic Diversity Of 266 Tomato Germplasm Resources And Evaluation Of Tomato Hybrid Combinations

Tomato germplasm resources are an important part of biological resources and the material basis for tomato breeding.In this study,genetic diversity analysis,correlation analysis,principal component analysis and cluster analysis were performed on 35 phenotypic traits of 266 tomato germplasms collected,and the genetic diversity and variation degree of the materials were determined.Based on the phenotypic data clustering analysis,138 representative germplasm materials were selected,and the core markers were screened from 374 pairs of SNP primers by KASP technique,and the germplasm cluster analysis was performed.At the same time,278 copies were collected for the previous phase.The tomato hybrid combination was used to investigate the phenotypic data.Using principal component analysis and membership function analysis,the relationship between the 24 indicators and the score function of each subject was constructed,and the hybrid combination was evaluated.The main findings are as follows:1.In the analysis of phenotypic traits,there are 60 variation types in 18 quality traits,the genetic diversity index is between 0.28 and 1.32,and the genetic diversity index of 17 quantitative traits is between 1.14 and 2.02,indicating that the collected materials are genetically diverse.The results of correlation analysis showed that there were significant or extremely significant correlations among the 17 quantitative traits.The principal component analysis extracted 7 principal components,and the cumulative contribution rate reached 70.95%.Phenotypic clustering results The materials are grouped into 8 groups.The first and second groups have high sugar content and comprehensive taste.The fruits of the third and fourth groups are mainly round and high,and the quality of single fruit is large.The seven groups of materials have great advantages in fruit quality and commodity characteristics.The eighth group of materials mainly consists of infinite growth,the shape of the fruit is mostly round,and the fruit color is mainly red.2.A total of 106 core SNP markers with high polymorphism were screened,and 324 alleles were detected by SNP typing.The average polymorphism information content was 0.343,which was moderate polymorphism;The similarity coefficient is between 0.155 and 1.055,and the average value is 0.667.Based on the SNP marker,138 materials are grouped into three groups,including 41,93 and 4 materials respectively.The population structure analysis divides the test materials into 4 Subgroup.3.The variation coefficient of 17 important fruit traits of 278 tomato hybrid combinations ranged from 13.44%to 86.65%,and the coefficient of variation of soluble solids was relatively high,being 31.59%,with an average of 6.79.The comprehensive taste evaluation was based on sweet acid.Mainly,the shape of the fruit is mainly high and round;the coefficient of variation of botanical traits ranges from 10.46%to 55.11%.On the basis of principal component analysis,the top 10 combinations ZJ7269,ZJ7234,ZJ7142,ZJ7229,ZJ7151,ZJ7268,ZJ7144,ZJ7148,ZJ7112,ZJ7167 with the best comprehensive performance were selected by comprehensive evaluation of membership function.The above research results laid the foundation for the collection,utilization and screening of tomato core germplasm resources in the future,and provided an important theoretical basis for cultivating good quality tomato varieties.