Correlation Analysis And QTL Mapping For Grain Traits And Quality Traits Of Common Wheat

Wheat is not only one of the most important food crops in China but even in the world,enjoying the title of "world food".People pay more attention to the quality of wheat foods as living standards have improved.Thus,improving nutritional quality becomes an important objective in wheat molecular breeding programs.The traditional way to evaluate the quality of wheat is testing the quality parameters.But wheat cultivars(lines)not only have a large groups,but the determination of quality parameter is laborious.Therefore,it is meaningful to find a method which can be used evaluate the quality of wheat via the grain characters during the wheat breeding programs.In the present study,we used CN17 and R146 as parent materials to create the RIL population.By analyzing the correlation and QTL mapping of the grain traits including grain length,grain width,test weight and thousand kernel weight and quality traits including falling number and sedimentation value of wheat,we can specify the genetic characteristics of grain traits and quality traits which can provide guidance in wheat breeding.The main results are as follows:1.We found grain traits and quality traits have a lot of variation in wheat by utilizing statistical analysis.The frequency of each trait and transgressive segregations of both parents were observed in the populations,suggesting that there are several great strains in the CN17/R146 population2.The correlation analysis indicates the grain length is significantly negative correlated with the test weight;the grain length is significantly positive correlated with the grain width;the grain length and grain width are significantly positive correlated with the thousand kernel weight;the falling number are significantly positive correlated with the sedimentation value;the grain length,grain width and thousand kernel weight are significantly negative correlated with the falling number and sedimentation value.Thus,it is reasonable we can use the grain character to evaluate the quality of wheat during the wheat breeding programs.3.The multiple regression analysis showed 18.7%of the total variance of falling number is decided by grain width and equation is Y ?=549.881-1212.125X?(R2=0.187),22.8%of the total variance of sedimentation value is decided by grain width and equation is Y ?=33.685-34.106 X ?(R2=0.228).Thus,grain width could be an important indicator to evaluate the quality of wheat.4.A total of 140 polymorphic markers were used for constructing genetic linkage map which covering 21 chromosomes of wheat by the software QTL IciMapping V4.1.27.9%markers were located in genome A,46.4%markers were located in genome B and 25.7%markers were located in genome D.The most molecular markers were located in genome B.QTL for grain length,grain width,test weight,thousand kernel weight,falling number and sedimentation value were located on 2D,1B,3B,4B,5B and 7B which indicates genome B shows the most polymorphic.5.Using Inclusive Composite Interval Mapping(ICIM-ADD)method in the software QTL IciMapping V4.1 for QTL analysis in the RIL population of the grain traits and quality traits,keeping LOD>2.0 as a threshold,a total of 8 additive QTL were detected on2D,1B,3B,4B,5Band 7B,respectively.QTL for grain length were located on 2D which could explain 15.19%of phenotypic variation;QTL for grain width were located on 2D and 7B which could explain 11.25%and 8.23%of phenotypic variation,respectively;QTL for test weight were located on 3B which could explain 11.97%of phenotypic variation;QTL for falling number were located on 4B and 5B which could explain 16.14%and 8.01%of phenotypic variation,respectively;QTL for sedimentation value were located on 1B and 5B which could explain 20.86%and 9.77%of phenotypic variation,respecatively.