Abstract:

In order to explore the authenticity of spaceflight induced wheat mutants, the Zhoumai 18 SP₅ mutant population created by the Shijian 10 satellite,and used 42 pairs of SSR markers and 55K SNP chip technology to identify the authenticity of four mutants with more significant differences in grain phenotypes.Grain phenotypic analysis revealed that the mutant population differed significantly in thousand grains weight and grain length,with the most abundant variation in thousand grains weight and insignificant difference in grain width,and the average grain length,grain width and thousand grains weight of the mutant population were significantly higher than those of the wild type,indicating the high frequency of beneficial mutations by space flight. SSR marker identification revealed that the mutant ZM18-112 differed from the wild type by 18 markers,with a high polymorphism ratio of 42.85%,while ZM18-105,ZM18-26 and ZM18-7 differed from their wild type by no more than three markers.The SNP chip identified that the percentage of SNP loci differing between ZM18-112 and the wild type was as high as 13.3012%,while the percentage of SNP loci differing between the other three mutants and the wild type did not exceed 0.7689%.It was believed that mutant ZM18-112 was a pseudomutant due to heterogeneous pollination or mechanical mixing,while ZM18-105,ZM18-26 and ZM18-7 had essentially the same genetic background as the wild type and were real mutants that had been mutagenized by spaceflight.

Key words: Wheat, Space mutagenesis, Grain phenotype, SSR marker, 55K SNP chip