Association Analysis Of Pre-harvest Sprouting Resistance Based On The Candidate-locus In White Wheat

Wheat is one of the most important food sources in the world, and its planting area and production reach the first worldwide, which feeds35%of the world’s population. In china, its production ranges the third just behind rice and maize with planting area of more than24million hm2each year. Its production is115million tons, accounting for about20%of the total food crop production. According to the difference of seed coat color, wheat can be divided into two categories:white; and red. The seed dormancy level of white wheat is shorter than that of red wheat, which is easy to cause pre-harvest sprouting.Pre-harvest sprouting is influenced by many factors, such as seed dormancy, amylase activity, and boycott in seed shell and so on. Pre-harvest sprouting resistance is a quantitative trait. Many QTLs associated with pre-harvest sprouting have been mapped, such as R gene and VP1on the homologous chromosome3, and a large number of molecular markers have been developed.In order to solve this problem, we screened420accessions which most are white collecting from different sources for pre-harvest sprouting resistance and mapped the QTLs according to association analysis through analysis of pre-harvest sprouting, population structure and genetic diversity. The results are as follows:1. We tested pre-harvest sprouting resistance and seed dormancy in420accessions which most are white. Four accessions highly resistance to pre-harvest sprouting (i.e. AS660365from United Kingdom, AS660608、AS660576from North USA, and AS660583from Finland) were screened. Correlation analysis among populations planted in different time and place, and between different methods and replications indicated there were significant correlated.2. The white wheat accessions are collected from forty-six countries. They have diverse genetic relationship, and population structure analysis divided them into four groups. Three hundred and forty-seven white wheat accessions were analyzed based on the50SSR markers which based on pre-harvest sprouting or seed dormancy. A total191alleles were detected, ranging from2to8per locus, with the mean of3.82.3. Eight candidate gene locus and ten SSR markers (i.e. Xbarc273, Xbarc372, Xcfd44, Xcfd49, Xbarc240, Xbarc275, Xbarc310, Xbarc330, Xgwm296and Xgwm610) on8chromosomes associated with pre-harvest sprouting were detected through association analysis on the traits and markers with mixed linear model in TASSEL3.0. The two SSR markers, Xbarc372and Xbarc273, were significant associated with the PHS resistance in all of the three environments. And the other markers can be detected only in one environment. Because the genetic distance was only9.8cM between Xcfd49and Xbarc273,10cM between Xbarc372and Xbarc240, the two SSR markers maybe associate with the same PHS resistance gene. These results should be valuable for the breeding of PHS resistance wheat.