Mapping Of Major QTLs For Kernel Shape In Wheat

Wheat?Triticum aestivum L.?is one of the most widely grown crops in the world.It is a major contributor to the world's diet and plays an important role in the production of food crops.Wheat kernel related traits such as thousand-kernel weight?TKW?,kernel length?KL?,kernel width?KW?,kernel length/width ratio?KLW?,kernel area?KA?and kernel perimeter?KP?are important indicators of wheat yield.Understanding the genetic basis of wheat resources and agronomic traits is important for the improvement of wheat varieties.It is important in both theory and practice to understand the genetic traits related to characteristics of the wheat kernel.By constructing molecular genetic maps,it is determined that the location and genetic effects of QTLs controlling wheat kernel-related traits play an important role in wheat breeding.In this study,the F₇ and F₈ RIL populations of 548 families were constructed by BYL8 and Dalibao,which was created by our laboratory as experimental materials.The genetic linkage map was constructed by SSR markers,and the six traits related to wheat kernel were constructed.QTL mapping was performed,and BSA and wheat 660K SNP chips were combined to determine the QTL for controlling the kernel length/width ratio traits of wheat.The main conclusions are as follows:?1?Six important kernel traits,kernel length,kernel width,kernel length/width ratio,kernel area,kernel perimeter and thousand-kernel weight of wheat RIL population and its parents were measured at four environments in 2 years.The results showed that the traits and kurtosis coefficients of the traits of the RIL population were less than 1 in the population,which was consistent with the normal distribution,and the populations showed super-parent separation in multiple environments.The thousand-kernel weight was significantly correlated with the other five kernel traits,and was significantly positively correlated with kernel length,kernel width,kernel area and kernel perimeter,and negatively correlated with kernel length/width ratio.?2?The constructed linkage map consists of 172 pairs of SSR markers with polymorphism in the parents,covering 4285.8 cM.The average distance between each marker is 24.9 cM.For a single chromosome,there are fewer SSR markers?3?on chromosome 4D and the genetic map is the shortest?37.05 cM?,chromosome 3B has the highest number of SSR markers?17?and the length of the genetic map is the longest?510.81cM?.?3?Using 172 SSR markers to construct a genetic linkage map,using the composite interval?CIM?mapping method to locate wheat kernel related traits?kernel length,kernel width,kernel length/width ratio,kernel area,kernel perimeter and thousand-kernel weight?QTL.A total of 31 QTLs were detected in 11 wheat chromosomes,including 1A,2A,2B,2D,3D,4B,4D,5A,5B,7A and 7D,and a single QTL in different environments explained1.32-15.29%of the PV.Among the detected QTLs,there were nine QTLs controlling kernel length/width ratio,seven controlling kernel area,five controlling kernel perimeter,five controlling kernel length,and four controlling kernel width.There is only one controlling thousand-kernel weight.?4?In this study,a total of 7 regions simultaneously controlled two or more grain traits to form QTL clusters.A significant correlation between QTL levels in kernel traits was demonstrated.?5?The position and interval of the main QTL controlling the kernel length/width ratio in the 2A chromosome were further determined and reduced by the 660K chip method,and its physical position was 751004612-779844131 bp.