Analysis Of QTLs For The Flat Ear Top And Other Related Ear Traits In Maize

Inbred line 092, which has the flat ear top, was crossed with Jiao51 to create F₂ population. 300 SSR primers, which were well-proportioned on chromosomes of maize, were selected to construct the linkage map and identify the QTLs of the flat ear top and other related ear traits. Furthermore, the correlation, heterosis, heredity and etc were analyzed for these traits. The main results were as follows:1.The heterosis over high-parent value was significant for ear length, ear diameter, kernels no. per row and length/width. Seven ear traits were analyzed for hereditary capacity. h_B² of the length of bare tip was the lowest, just as 12%, which indicated that the length of bare tip was sensitive to environment. Length/width, ear diameter, no. of rows per ear, cob diameter, ear length and no. of kernels per row were arranged in decreasing order of h_B². Except for length/width, no. of rows per ear and no. of kernels per row, all other ear traits were normally distributed.2.300 SSR primers were used to detect the SSR polymorphism between parents 092 and Jiao51. 94 polymorphic SSR were obtained in all. A SSR linkage map of 13 linkage groups was constructed. The 13 linkage groups covered 90 loci and spanned maize genome about 841.86cM, with average distance between makers being 9.35cM, which was fit for preliminary QTLs mapping.3.With interval mapping procedure, 5 QTLs were identified for length/width, which could account for 39.9% of phenotypic variation totally. 2, 7, 6, 1, 6, 2, 3, 2QTLs were respectively identified for ear length, ear diameter, no. of rows per ears, no. of kernels per row, cob diameter, 200-kernel weight, kernel weight per ear, ear weight and QTLs totally accounted for 16.1%, 48.9%, 58.5%, 17.7%, 64.7%, 11.9%, 27.1%, 11.5% of phenotypic variation of each trait. But none QTL was detected for the length of bare tip of ear.4.Length/width was significantly correlated with ear diameter, highly significantly correlated with no. of rows per ear and cob diameter. According to QTLs analysis, 2 QTLs were identified on chromosome 1 and chromosome 6 for length/width; meanwhile the 2 QTLs were both identified for ear diameter, no. of rows per ear and cob diameter. It was presumed that length/width affected yield by these QTLs acting on no. of rows per ear and ear diameter.5.For the traits significantly correlated, 1 to 3 of QTLs were detected at the same locus on chromosome except for few traits. It was presumed that pleiotropic effects or linkage of QTLs might lead to correlation between traits.