QTL Mapping And Molecular Markers Development For Thousand Grain Weight Related Traits Of Wheat (Triticum Aestivum L.)

Wheat as the main food crop,to improve its production and quality are of great significance to the world's food security.Thousand kernel weight is one of the three elements of wheat yield and to improve kernel weight is an important approach to improve wheat yield.Kernel length,width and thickness are components of thousand kernel weight,and are the important factors that affect thousand kernel weight.The present study conducted unconditional and conditional QTL mapping for thousand kernel weight and its elements based on SNP marker high density genetic map that constructed based on 173 recombinant inbred lines derived from “Shannong01-35×Gaocheng9411”,at the same time develop CAPS markers with thousand grain weight.In addition,using the method of comparative genomics and develop new chain of molecular markers in the target segment.The main results of the present study as follows:?1?A total of 18 QTLs were detected for thousand kernel weight and kernel shape,which located on chromosome 1B,1D,3B,4B,5A,5B,6A,6B and 6D,and explained 5.8%-39.07% of phenotypic variation.Of which,QTKW4 B.4-14 located on the chromosome interval of RAC875₆11-EX_C1₇05,and can be detected in all the environment,explaining 26.52%-39.07% of the phenotypic variation.In addition,QKW4 B.4-14,QKL4 B.4-14,QKT4 B.4-14 and QKL/W4 B.4-14 were all located on the same interval,and genetic contribution rate were greater than 10%.?2?Conditional QTL mapping was conducted to analysis the relationship between thousand kernel weight and kernel shape at the QTL level.As a result,total of 18 QTLs were detected,and eight of them were both detected in conditional and unconditional QTL analyses,the remaining were new detected QTLs.The results indicating that the effect of QTLs for TKW were influenced by kernel length,kernel width,kernel thickness,but different QTL under the influence of the grain traits are inconsistent.?3?According to the SNP marker RAC875₆11 and EX_C1₇05,4B-CAPS1 and 4BCAPS2 markers were developed with restriction enzymes of APal I and AluI.Maker validation results indicated that 4B-CAPS1 and 4B-CAPS2 are chain of molecular markers for thousand kernel weight and kernel shape,and can be used for marker-assisted selection.?4?According to comparative genomics,RAC875₆11-EX_C1₇05 chromosomal region was compared with the genome sequence of rice and slender false brome grass.Results showed that the RAC875₆11-EX_C1₇05 chromosomal region with the third chromosome region OS03G0704700-OS03G0709000 of rice and the first chromosomal region of false brome grass BRADI1G11027-BRADI1G11220 exist good linear relationships.In addition,dwarfing gene Rht-B1 within the target area,from RAC875₆11 and EX_C1₇05 genetic distances were 1.5cM and 2.3cM.?5?Then,in the Rht-B1-EX_C1₇05 interval,molecular marker TaTKW-4B was developed,from Rht-B1 and EX_C1₇05 genetic distance of 1.7cM and 0.6cM,respectively,marker validation results show that this maker is link to target gene.In addition,the final QTL analysis shows that the control of grain weight and grain traits QTL may locate in Rht-B1-TaTKW-4B range,but it needs to be further validated.