SSR ALLELIC VARIATION OF RICE VARIETY HANGXIANGNUO BRED BY SPACE MUTATION

Hangxiangnuo,an indica fragrant glutinous rice mutant,was induced by space environment.Comparing with its wild type Nanfengnuo,the yield and blast resistance of Hangxiangnuo are improved significantly and the grain shape became slender and with fragrance.To understand the mechanisms of space mutation and identify the changes at molecular level associated with phenotypic variations,SSR allelic variation analysis were performed on Hangxiangnuo and Nanfengnuo in this study.The results showed that 45 loci were polymorphic among the 156 SSR loci tested throughout the genome,the frequency of variation was 28.85%.Among the polymorphic loci,42 loci only showed variations in the molecular weight of the amplified bands,only one locus increased the number of amplification bands in Hangxiangnuo and two loci were differed by heterozygous loci(with two amplification bands at one locus) detected in Nanfengnuo and homozygous loci in Hangxiangnuo.It suggests that the change of some loci in mutants was due to the normal segregation and recombination of heterozygous loci of the wild type.The variation frequencies among different chromosomes were quite different,with the highest one at 50.00% detected on chromosomes 7,8 and 12,and the lowest at 6.25% on chromosome 6.The polymorphic loci were clustered on chromosomes throughout the genome indicating that large DNA segments mutation is one of the major variation patterns induced by space environment.Some of reported QTLs involved in grain shape,yield,fragrance and blast resistance were found to be located exactly in the mutated regions.Therefore,further study is needed to confirm that these QTLs are responsible for the trait variations.