QTL Mapping Of Kernel Shape Related Traits Using A Four-way Cross Population In Maize

Maize is the most important crop of food and fodder, increasing the yield of maizewas a major target of corn breeding, the kernel shape related traits is one of the mostimportant factors to constitute yield traits. This study using a four-way crosspopulation (276/72//A188/Jiao51) which constructed deriving from the inbreed line72,276, A188and Jiao51which having significant differences in the kernel shaperelated traits and having actual application value in breeding. Detecting the phenotypeof the kernel related traits in different environments and analysising their geneticcharacteristics. Using MQM mapping to map QTL loci and analysis gene effect oneach traits on the foundation of building genetic linkage map of SSR molecularmarkers.The main results in this study were as follows:1. Three kernel-related traits (kernel length, kernel thickness, kernel width) of thefour parental inbred lines276,72, A188, Jiao51and F2family were identified andanalysed in Jiyuan and Zhengzhou environment. The results showed that: In bothenvironments, the various traits in the parents show a very significant difference inaddition to grain width in inbred lines of276and72; the average value of all traits inthe F2family show a very significant difference. The results showed that thedistribution of Three grain shape traits was continuous and normal distribution and itcan be used for further location of QTL in F2family of the four-cross populations.2. Eighteen QTLs of grain thickness were detected in both environments andpooled analyzes, which are located on the chromosome1(7),3(2),4(1),5(5),6(2),10(1). A single QTL could explain the phenotypic variation between5.3%and16.7%.qKT1c located the range-point bnlg1643-bnlg1671of chromosome1has themaximum contribution rate of15.6%in the pooled analyzes. qKT1b, qKT1c weresimultaneously detected in two environments or three environments, at the regionumc1590-phi039and bnlg1643-bnlg1671respectively. qKT1a and qKT1g havecommon overlapping region1.02-1.03; qKT1c, qKT1f and qKT1g have the sameoverlapping region bin1.02; qKT5a、qKT5b、qKT5d and qKT5c、qKT5e have the sameoverlapping area bin5.02and5.05-5.06respectively. Overlap region may be the thehot spot control the traits, which resulted by interaction between major QTL and different environmental.3. Twelve QTLs of kernel width were detected in both environments and pooledanalyzes, which are located on the chromosome1(2),3(1),4(1),5(3),6(1),7(2),10(2).qKW6a、 qKW7a、 qKW7b and qKW10a were simultaneously detected in twoenvironments, at the region phi126-umc2314, umc1642-umc2364, dupssr13-phi082and phi118-umc1152. qKW5a and qKW5c have the same overlapping region5.03-5.04. A single QTL could explain the phenotypic variation between5.3%~10.7%, qKW7a located the range-point umc1642-umc2364of chromosome7has themaximum contribution rate of10.7%in the pooled analyzes.4. Thirteen QTLs of kernel length were detected in both environments andpooled analyzes, which are located on the chromosome2(1),3(1),4(1),5(4),6(1),7(1),10(4). qKD10c and qKD7a were simultaneously detected in Zhengzhouenvironments or in the pooled analyzes, at the region bnlg2190-umc1569andumc1408-phi082; qKD10b and qKD10d have the same overlapping region10.04-10.05; qKD5a and qKD5b have the same overlapping region5.05-5.06; qKD5cand qKD5d have the same overlapping region5.06-5.07. A single QTL could explainthe phenotypic variation between5.2%-21.4%, qKW5d located the range-pointumc1990-zct389of chromosome5has the maximum contribution rate of21.4%inthe pooled analyzes.