Genetic Diversity Of Rice Varieties And Establishment Of Fingerprinting Of Hybrid With Microsatellite Markers

SSR was used to study the polymorphism of 93 rice varieties and the relation between the genotype of waxy and the amylose content. The detail results were as follows.1. 123 primers of 208 have polymorphism. The results showed significantly higher genetic diversity on chromosome 9 and 10 and considerably lower diversity on chromosome 12. Thirty-eight SSR primers were used to evaluate the genetic diversity of 55 indica and 38 japonica varieties. A comparison of the two parameters of the average genetic multiplicity (Hs) and the average number of alleles per locus (Ap) indicated that the genetic diversity of indica is higher than that of japonica. At the 38 loci investigated, the number of alleles of japonica is only about 80.7% of that of indica.Through clustering on SSR primers, the relationship and hereditary base of 93 varieties and 42 parents of hybrid were evaluated in the project. All materials used in the study were clustered into indica group and japonica group which are generally agreed with pedigree analysis. The results indicated that SSR markers play an important role in variety identification and study of genetic diversity.2. 123 SSR primers were used to detect ninety-three major parents that were widely utilized in the southwest region. Primers analyzed the polymorphism among 42 widely used parents of hybrid rice and their fingerprinting maps were constructed. Generally, important parents of hybrid rice can be identified by their particular primers.Out of the primers, 12 and 10 respectively were selected and they were polymorphic between two parents, which were adapted to examine purity of hybrid rice seed. The result showed that hybrid purity of seeds can be identified with one or two of the primer and the result is agreeable with the result of the field. The experiment showed that SSR technique has broad applicability in variety protecting and purity identification.3. The polymorphism of (CT)n of PCR products amplified by microsatellite marker 484/485, and the relationships between genotype and amylose content were studied. In addition, the amylose content in mature seeds of these cultivars was determined. The correlation of Wx genotype and AC is 0.852** that is correlated to AC at very significantlevel. Which means 85.2% of amylose content variation could be resulted from waxy gene allele difference. Wx1 Wx1 and Wx2Wx2 genotype showed significantly lower amylose content and Wx3 Wx3 genotype higher amylose content.A PCR-Acc I molecular marker has been developed and used to determine whether the first nucleotide of splice donor site of waxy intron 1 is G or T in 93 rice cultivars collected from different areas. The results show that the amylose content in the cultivars with base G at position +1 of waxy intron 1 is always above 16%, while that in all of the cultivars with base T at the corresponding position is below 16%. The correlation of PCR-Acc I genotype and amylose content is 0.701**. Most Wx1Wx1 and Wx2Wx2 genotype is TT genotype and most Wx3Wx3 genotype is GG genotype. The correlation of Wx genotype and PCR-Acc I genotype is 0.665** that is correlated at very significant level. Thus this PCR-Acc I molecular marker can be used to screen combinations for lower amylose content of grains and therefore better eating qualities.