Association Analysis Between Yield Traits And SSR Markers In Synthesized Hexaploid Wheat

Wheat(Triticum aestivum L.) is one of the most important crops among the world. It plays a vital role not only in domestic livelihood, but also in national defend. Numbers of quantitative traits related to wheat yield are controlled by series of Quantitative Trait Locations(QTL). Research on those QTLs will promote wheat breeding, especially on selection dependent on molecular markers. Association analysis is based on Linkage Disequilibrium(LD), which can be used in association between target traits of nature populations and genetic markers or candidate-gene sequence. Association analysis can locate QTLs precisely. The D-genome of Synthesized Hexaploid Wheat( SHW) Introduced from CIMMYT has been developed, which may provide richer genetic diversity.In this research, 128 wheat germplasms consisted of 86 SHW and 42 general wheat varieties were detected, including spike number per plant(SPP), grain number per spike(GPS) and thousand kernel weight(TKW). 102 simple sequence repeat(SSR) markers were selected, and 102 pairs of SSR primers were amplified by PCR, in order to clarify population genetic diversity, population structure Q and the kinship K. Analysis method was decided by SAS. Finally, association analysis between traits and SSR markers was performed under General linear Method(GLM) through TASSEL. Results are shown below.1. The phenotype data between SHW and general wheat materials shows difference. The yield traits of these 2 kinds of material play different importance to yield. For general wheat, SPP devote the most to yield, while GPS effects yield mostly for SHW. The average amount of TKW of those materials reveals no significant difference. Correlation of yield traits was influenced by plant type to a certain level.2. Six hundred-sixty seven allele varieties are detected among 102 SSR markers, withthe average of 6.54. Average Polymorphism Information Content(PIC) reaches 0.7236, with the maximum of 0.8971. Those reveal the abundant genetic diversity of population. Population is divided into 3 subgroups by both SAS8.1 and STRUCTURE2.3.4. SHW and the general wheat are absolutely divided into different groups, which demonstrate the almost entirely different genetic backgrounds of them.3. Six significantly associated SSR loci are confirmed by GLM analysis of TASSEL with 2 showing very significant correlation. Among them, 1 marker is associated with SPP, 2 markers are correlated with GPS and the rest with TKW. There are 4 other markers associated with SPP and GPS to a considerable level. All of these loci are located in chromosome A and B, with the latter owning more loci. The very significant association between GPS and GWM-389 on 3B has been supported by former research. Some other markers were found associated with physiological traits and yield related traits. This may indicates the multiple foundation of SSR marker.The interpretation ratio of these 6 loci to relevant yield trait is calculated from 6.96% to 20.24%, with the maximum belonging to GWM-388. Those results may build foundation for Synthesized Hexaploid Wheat on Molecular Marker Assisted Breeding.