QTL Mapping For Kernel Test Weight Related Traits And General Combining Ability Of Maize

Test weight is an important index of maize quality,and it is also an important parameter to classify maize grade.In this study,F₁ population,natural population and RIL population were used as materials and test weight related traits were analysised to detected loci associated with test weight.Furthermore,candidate genes were excavated above of which would provide guidance for maize breeding.The results of the study were performed as follow:1.17 loci associated with GCA were detected of which 6 loci were for GCA of test weight and 4,1,1,5 loci for GCA of contents of moisture,protein,fat,lysine respectively.Importantly,2 co-localized SNP loci were detected in both test weight and GCA of contents of moisture and lysine respectively.2.In natural population,203 SNP loci were detected with 83 loci being divided into high density and 120 divided into low density.4 and 2 loci associated with test weight were detected in low density and high density.In low density,18 loci associated with quality traits were detected.21 loci were detected associated with ear traits and 40 loci were detected for kernel traits.In high density,10 loci were detected for quality traits.36loci associated with ear traits were detected and 72 loci were detected for kernel traits.3.In RIL population,52 QTLs were detected linked with test weight and related traits.2 QTLs were detected for test weight distributing on chromosome 3 and 7.QTLs linked with contents of moisture,protein,starch and lysine were detected for number of 4,1,3,3additionally,3,1,3,3,3,3,2 QTLs were detected for ear length,kernel thickness,row numbers,kernel numbers per row,ear weight,kernel weight,kernel percentage,furthermore,2,2,4,2,4,1,3,3 QTLs were detected linked with hundred grain weight,hundred grain volume,kernel area,kernel length width ratio,kernel length,kernel width,kernel diameter and kernel roundness respectively.4.Compared the results of association analysis with linkage mapping,locus chr3₁57053031 associated with GCA of test weight was along with QTL interval153.06Mb¹56.25Mb and locus chr7₁987513 was closed to QTL interval 2.35Mb⁷.10Mb.Locus chr2₁97222744 associated with contents of moisture GCA was located at QTL interval 193.98Mb¹98.62Mb.5.Candidate gene belonged to Trihelix family genes related to regulating growth and development of plants and stress resistance was detected nearby the locus chr10₁41022877 which was co-located by test weight and contents of lysine.Candidate genes belonged to Leunig family which was related to growth of seed outer integument was detected near locus chr5₂15358939 associated with both GCA of test weight and contents of lysine.Candidate gene MADS24 belong to MADS-box family genes regulating flowering and growth of floral organs of plants was detected nearby locus chr1₂77354083associated with contents of moisture and combining ability.Opaque2 heterodimerizing protein 1 a homologous gene with opaque2 was detected nearby locus chr1₂88199229associated with contents of lysine.In this study,kernel test weight and general combining ability were analyzed using genome-wide association studies resulting association loci of test weight and general combining ability were detected,furthermore,candidate genes nearby the association loci were inquired.Besides,linkage mapping for RIL populaition was carried out and QTLs related to test weight and related traits were detected.In addition,comparison for results of association studies and linkage mapping was analyzed.The results of the study would provide valuable theoretical guidance for quality breeding in the future.