Studies On Genetic Diversity Of SSRs In Japonica Of Primary Core Collection Of Rice Landrace In China

It studied the genetic differetiation between Indica (1313 accessions, the data comes from Sun Junli's MS disseration, 2003) and japonica (1395 accessions), and the systematic and geographic genetic diversity and differentiation in Japonica. At the same time, it also studied the composition of SSR primers in establishing core collection and the relationship between initial population size and sampling proportion. The results were summarized as,Genetic diversity and differentiation in 37 loci of 36 SSR primers showed that the average gene diversity of Indica was a little higher than that of Japonica. The coefficient of genetic differentiation between Indica and Japonica was from 0.012 to 0.233. One indica-speciflc allele (RM270-08) and four japonica-speciflc alieles (RM258-13, RM262-06, RM23-12, RM267-13) were determined. The hiberarchy of genetic differentiation showed in this study identified the taxonomy under O. saliva L put forward by Ding Ying. Genetic diversities in Japonica were different among rice zones and subzones, and decreased from south to north in general.Studies on different primer compositions (different combination of primer number and polymorphism) showed that randomly sampled 36 SSR primers were enough for the establishment of core collection and the estimation of its genetic diversity.Studies on relationship between population size and sampling proportion revealed that population size had evident impact on the sampling proportion and retainment of variations in core collection. The larger the population was, the less sampling proportion could be and the more variation could be retained in the core collection. For a population with about 50000 accessions, the sampling proportion could be low as 5% and the retainment of variation could be more as 90%.