Corn Stem Diameter QTL Mapping And Genetic Analysis

Corn, one of the three major food crops, is not only a major source of food and feed, but also an important industrial raw material, its yield and quality of great significance to China’s social and economic development. China’s com production has more than 200 million tons, and showed an increasing trend. Practice has proved that the lodging is an important limiting factor in corn "high stability excellent" production. With the development of cultivation techniques, and the high-density planting techniques of com hybrids produce, combined with climate warming and natural disasters continue to occur, com lodging has occurred and the trend of com lodging is increasing year by year.Stem diameter,an important agronomic traits of maize, one of the important factors that also affect lodging resistance, has caused great concern of breeders. Thus, genetic research on the cultivation of lodging-resit maize varieties have some significance. In this study, we select maize inbred line 478 andO8-641 as parents build 266 F2:3 families as a mapping population, Using SNP marker technology and complete interval mapping,we detected maize stem diameter QTL in Nanning, Jinghong, Ya’an-1, Ya’an-2 four environmental. The main results are as follows:1, In this study,we constructed a genetic map included 258 SNP markers, covering 10 chromosomes of maize, the total map length was 1710.28cM,1-10 chromosome length was 276.56 cM,227.54 cM,126.52 cM,157.91 cM,160.09 cM,168.65 cM,158.06 cM, 149.31 cM,141.16 cM,144.46 cM,respectively.the number of markers on 1-10 chromosomes were 47,33,17,25,25,30,23,17,23,18, respectively.average distance between markers was 6.63 cM.2, Using the complete interval mapping, we detected 15QTL of maize stem diameter in Nanning, Jinghong, Ya’an-1,-2 Ya’an. No consistent QTL loci was found in four different environments, Of the 15QTL,nine were detected in Nanning, located on chromosome No.1,4,6,7,8,9,10.contribution rates were 3.53%,4.69%,3.48%,3.74%, 5.13%,6.07%,5.82%,3.54%,4.60%, QTL cumulative phenotypic contribution rate was 40.60%; and three detected in Jinghong, distributed on chromosome No.1,6, contribution rates was 4.93%,5.22%,7.42%, QTL cumulative phenotypic contribution rate was 17.57%;one was detected in Ya’an-1 (2012), located on chromosome 5, the contribution rate was 4.52%; two were detected in Ya’an-2 (2013), located on chromosome No. 2,10, the contribution rate of 10.79%,4.43%, respectively, the cumulative phenotypic contribution was 15,,22%.