| With a long history of rice cultivation, abundant rice landrace resources were accumulated in Tai Lake Region. Studies on the genetic diversity of rice landrace resources can provide reference for the protection and utilization of high-quality germplasm resources, and also for new variety breeding. In this study,23intragenic molecular markers related to starch-synthesis-genes were chosen to identify genotypes of549rice landrace samples from Tai Lake Region, in order to analyze their genetic diversity. And further, a total of92modern bred rice varieties were uesd to compare with these landraces. On the other hand,48evenly spaced SSR markers were used to scan the population structure of selected314varieties from549landraces based on the starch quality genotypes. In addition, association analysis was carried out between the SSR markers and starch quality traits based on population structure. The results were showed as follows:(1) In landrace population, a total of53alleles were detected by23intragenic molecular markers related to starch-synthesis-genes, with an average of2.94per loci. The average genetic diversity was0.2104, varying from0.0109to0.6476; the average PIC value was0.1847, varying from0.0108to0.5864. Whereas in bred variety population,46alleles were detected, with an average of2.94per loci. The average genetic diversity was0.1749, varying from0.0430to0.5286; the average PIC value was0.1538, varying from0.0421to0.4199. (2) By integrating the alleles at the detected locus, there were107genotypes in landrace population.65of them could only be traced to the same variety, while other genotypes were detected from several or even dozens of varieties. There were32genotypes in bred variety population, but only3of them were also in landrace population. Both gelatinization temperature and gel consistency were showed significant difference among genotypes.(3) A total of257alleles was detected by48SSR markers covered the entire rice genome from all the314landrace samples, with an average of5.35per loci, varying from2to13. And among them,41rare alleles(gene frequency less than1%) were found in30locus. Average genetic diversity of SSR loci was0.3869, varying from0.0063to0.8806; the average PIC value was0.3637, varying from0.0063to0.8688.(4) The314landraces were grouped into five subpopulations based on population structure analysis. Within1128combinations of two loci among48SSR locus, the proportion of unbalanced pairs of sites supported by statistical probability (P<0.001) was92.6%, and the percent of combinations (D’>0.5) was67.0%. For the whole population, LD was ubiquitous for distances<150cM.(5)21SSR markers were found to significantly associate with2starch quality traits by association analysis based on population structure. Among them,11SSR markers associated with GT, which could explain39%of the variation, and10SSR markers associated with GC, which could explain nearly29%of the variation. |
PDF Full Text Request