The Genetic Analysis Of Maize Yield Related Traits

Maize is one of important crop plants, and is widely used for food, feed and biofuel; high yield is a major goal of maize breeding. The grain yield of maize is controlled by quantitative trait loci(QTLs) with complex genetic basis. At present, the research on maize yield focus on QTL mapping of yield-related traits. Genetic dissection of these complex traits can provide important information for breeding. In this study we used maize inbred lines TY6 with high kernel row number(KRN) to cross with Mo17 and W138 they have less KRN, respectively. Two F2: 3 mapping population derived from TY6×Mo17(TM) and TY6 × W138(TW) are developed for identifying QTL for yield-related traits. The main results were as follows:1.With 190 respectively(TY6 x Mo17) and 275(TY6 x W138) F2 segregation for drawing groups, through the use of 174 and 165 SSR markers we constructed two sets of covering the whole genome of genetic linkage maps, the results were take advantage of QTL analysis for whole genome. The map of TM group: total length was1878.6 c M, and the average spacing was 10.8 c M; the map of TW group: total length of map was 1909.2 c M, and the average spacing was 11.6 c M.2. Using composite interval mapping(CIM) QTL mapping unit point method to deal with the two F2: 3 separated groups, 99 QTLs were detected, these QTLs were mainly distributed in 1, 3, 4, 5, 6, 7 chromosome, and 20 kernel row number(KRN)QTLs were detected and its effect is the largest, and most. One hundred kernel weight was the least :eight QTLs were detected in toatl. The TM group found out a total of 39 QTLs, individual QTL can explain the phenotypic variation of 0.4% to 22.3%. TW group found out a total of 60 QTLs, individual QTL can explain the phenotypic variation of 0.87% to 31.64%. Mainly in PVE is more than 10% effect QTL division,QTL were detected in 35 main effect QTLs, the ear weight found eight main effect QTLs, ear row number seven, ear length, kernel number per row, cob weight each four,ear diameter and cob diameter each three, one hundred kernel weight only found two effect QTLs.3.We analyzed the detected QTLs position distribution and found out 5 QTL enrichment regions. It involves extremely significant correlation between these traits,such as ear length and kernel row number, ear diameter, cob diameter and kernel number per row are rendered highly related to the cause of these sites are likely to exist a multiple effect. The TM group was found out three QTL enrichment regions,respectively located in chromosome 1, 4, 5; TW group was found out two QTL enrichment regions, is located in chromosome 4, 5, respectively.