Method of selection of superior normal japonica rice parental combinations and its breeding application
[Objective]The normal japonica rice parents were classified based on the concurrent understanding of phenotypic and genotypic differences.The classification was then integrated with the four parental selection principles to identify superior parents and produce a paren-tal selection approach for conventional rice breeding.[Method]In the experiment,42 phenotypic traits of 34 varieties from Jiangsu province were investigated,and these varieties were genotyped using 41 pairs of SSR markers.Euclidean distance and genetic similarity coefficient were calculated by phenotypic and genotypic values respectively,and then cluster analysis was performed by Ward.D method and UPGMA method.[Result]The majority of the test varieties had relatively similar genetic base backgrounds,according to genetic similarity analysis of agronomic and quality traits,but genetic similarity analysis of SSR markers showed that the genetic similarity coefficients among the 34 varie-ties ranged from 0.39-0.95,indicating that the genetic backgrounds of the varieties bred in different institutions in Jiangsu were still differ-ent.The results of cluster analysis showed that there was no obvious correlation between agronomic traits,quality,and allele differences and different ecotypes among the different clusters.96.19％of the genetic variation in the test varieties came from within the population,accord-ing to an AMOVA study.[Conclusion]The clusters obtained from different cluster analysis are not identical.Combining the clustering re-sults of agronomic traits,quality traits,and SSR markers to classify the parents is more conducive to increasing the precision of parent selec-tion,reducing the workload of breeding,and increasing the efficiency of breeding.In the combination of Zhendao 18 and Yandao 11,a vari-ety of index clustering methods were applied for conventional japonica parental selection.A large number of excellent intermediate materials were selected,and new varieties of different ecotypes,Zhendao 23,Zhendao 32,and Zhendao 33 were bred.
Normal japonica riceParent combination selectionGenetic similarity analysisCluster analysisAMOVA analysis
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