Molecular Analysis Of Yield And Quality Traits Of Sichuan Wheat Landraces

Wheat (Triticum aestivum L.), as the largest acreage crops in the world, which yield is only inferior to maize. Wheat is the third largest food crop in China, as the Chinese people will be continued to increase and the available cultivated land will be decreased, on and on, to further improve the yield potential is the eternal theme for China’s wheat breeding Nowadays, with the people’s living standard and the level of wheat processing technology’s improving, the breeders will be required to pay more attention to improve the wheat quality. Most of yield-and quality-re la ted traits of wheat are all quantitative traits, so the quantitative trait loci (QTL) are mainly uses the method of Family-based linkage analysis, Natural population-based association analysis to study. Currently, the association analysis with characteristic of short cycle, high precision, multi-detection sites and commonly used in the studies of quantitative traits.In this study, the germplasm materials which consist of 64 wheat landraces were adopted in Sichuan. It was based on yield and quality-re la ted phenotype analyse, distributed in 21 chromosomes of 134 SSR markers and 17 traits association analysis. To reveal the important of genomic segments and key sites with yield and quality related traits of Sichuan wheat landraces, providing the evidence for molecular breeding to use Sichuan wheat landraces with yield and quality-related traits. The main results are as follows:1. Using uniformly distributed over 21 chromosomes of the 108 SSR markers for genetic diversity analysis, were detected 539 alleles allelic variation in the range of 2 to 10, the average SSR markers detected allelic 4.99 variation. The polymorphism information content index (PIC) varies 0.18-0.83, with an average of 0.51. Moreover, these confirmed that the Sichuan wheat landraces have rich genetic diversity, can be used for association analysis. Further analysis found that in A, B, D three genomes, Sichuan wheat landraces in the D genome has a high diversity,,while, A genome has low diversity. The allelic variation and diversity of information content which were expressed as D>B>A. Combined with UPGMA clustering model and population structural analysis, the Sichuan wheat germplasm were divided into two groups2. Through population structure and association analysis combined with 3 environment phenotypic identification was found,14 were detected in yield-and quality-related traits and 28 SSR markers to stabilize extremely significant association. Of these,19 SSR markers associated with yield-related traits, nine SSR markers associated with quality -related traits. Among them, a total of eight SSR markers associated with Spike length, and Xgwm372 markers simultaneously with ear length, tolerance index, formation time, sedimentation value and the evaluation value reached highly significant association. Meanwhile,we found on chromosome 2A, the Spike length significantly associated with Xgwm448-Xgwm328 and Xgwm328-Xgwm372 sector, and the sector sizes is 6cM and 2cM,respectively.3. Taking the phenotypic mean of carrying null allele genes as a reference, to evaluate the potential allelic variation of phenotypic effect increment and reduction. Allelic variation of association sites need to further genetic analysis. For eight yield-related traits conducted loci analysis, were found 12 significantly associated yield-related traits superior allelic variation; and on six qualities associated with related traits markers excellent locus analysis, found a total of 9 superior allelic variations associated with quality traits.Based on the above results, this study found a group of yield- and quality-related traits associated with elite alleles, allelic variation and the excellent allelic variation of genetic resources. It can make up for the inadequacy of the family chain method of QTL mapping information and direct use of allelic variation in parental selection information The combination of assortative matching and offspring allelic variation assisted selection, laying the foundation for the effective use of local varieties of wheat and explore Sichuan excellent genetic resources.