Genetic Diversity And Association Analysis Of Restorer Lines In K-type Cytoplasmic Male Sterile Wheat

Wheat is the major crops in the world,which is the main food crop in most regions of China.For a long time,the plant breeders are committed to improve the wheat yield,quality and resistance.It's very improtant for improving wheat productivity to use CMS(Cytoplasmic male sterility)way to screensuperiority combination,breedrestorer lines and analyse diversity of the restorer lines.This research,mainly using wheat K-CMS restorer lines as materials,were used to conduct multi phenotypic identification of agronomic traits;obtain genotype data using SSR(Simple sequence repeat)and KASP(Kompetitive Allele Specific PCR)markers covering wheat genome.By the analysis of genetic diversity and population structure,association analysis between genotype and phenotype was carried out.The results are as follows:1.The marker-trait associations were studied with 134 wheat K-CMS restorers' genotypes using 215 SSR markers and 35 KASP markers distributed throughout the wheat genome.By genetic diversity analysis of SSR markers loci,the result showed that the range of genetic diversity of varieties tested between chromosomes is 0.000~0.803,the GD average is 0.287.The SSR markers loci polymorphism information index(PIC)at the level of whole genome chromosome variation range is 0.000~0.774,the average is 0.244.The results are consistent with using KASP markers.The trend of the change between GDand PIC in whole genome showed B > A > D.This result indicated that the genetic diversity of varieties tested in our study is fairly rich,which is suitable for using in further correlation analysis.2.The analysis of population structure indicated five subpopulations appeared in wheat K-CMS restorer accoding to UPGMA.The results showed GS ranged from 0.18-0.34,the average is 0.29.Structure population divided into five subpopulations.There are different levels of linkage disequilibrium between SSR markers or KASP markers.The analysis of linkage disequilibrium(LD)revealed LD decay of the whole genome was 9.85 cM.3.This experiment is used TASSEL3.1 software(GLM and MLM model)to associated genotype and traits.Using the GLM-K model,there are 172 SSR and 74 KASP markers significantly associated with 6 agricultural traits at the P<0.05 level,the numbers of SSR associated with 6 agronomic traits(PH,UNL,UIL,FLL,FLW and SL)were 39,34,43,41,49 and45.In which 67 markers were detected above 3 environments using the MLM-K+Q model.In addition,using the MLM-K+Q model,a total of 154 SSR and 69 KASP markers high significantly associated with traits were detected at the P<0.05 level,The numbers of SSR association loci with 6 agronomic traits(PH,UNL,UIL,FLL,FLWand SL)were 34,22,34,37,50 and46,respectively.In all 57 markers were detected above 3.4.Using GLM and MLM model,a total of 33 markers were associatated with fertility restoration of restorer lines were detected(P < 0.05 level).Significantly markers were located on the chromosome 1B,2 A,2 B,2D,3A,5A,5 D and 7 D.The results of 1Band 2A chromosome are consistent with previous studies.