Mapping QTL For Kernel Oil Concentration And Analysis Of Effect With High-oil Maize

High-oil maize is an artificial new type of maize with high extra value. Its kernel has not only high concentration of oil and total energy, but also execellent quality protein. Thus, the development of high-oil maize has been paid more and more attention. Since oil concentration in maize grain is controlled by multi-genes, traditional high-oil corn breeding has low efficiency based on individual selection for phenotype. With the development of molecular marker technology, quantitative trait locus could be mapped to analyze in whole genome.The objectives of this study were to optimize genetic map by SSR markers, identify oil concentration QTL and evaluate these QTL effects using composite interval mapping using 298 By 804×B73 _2∶4 families which has three replication of field experiment. These results will do great help to fine mapping for QTL associated with kernel oil content and marker-assisted selection in high-oil maize breeding. The study also analyzed the relationship between oil and related traits in kernel. The major results in this study are as follows:1. 104 SSR primers were employed to screen polymorphism between two parents, By804 and B73. Only 34 markers (32.69%) were co-dominant segregation. Ultimately, 183 SSR markers were assigned to 10 linkage groups. A total length of the linkage map equals to 1605.7 cM, with an average interval of 8.77 cM.2. Six QTL were significantly associated with kernel oil concentration. The phenotypic variation explained by a single QTL ranged from 4.34 to 13.13%. Effect of partial dominance as well as additive appears to play important roles in controlling kernel oil concentration. A total of two QTL and four QTL were consistent with QTL in F₂ and F₃, accounting for 33% and 67% respectively. Of six QTL for oil in this study, five QTL had the same or similar confidence intervals to those QTL for oil concentration in experimental materials with different genetic background in precious study.3. One of oil QTL, oilcl, located on chromosome 1 and linked to flanking markers, bnlg2086 and umcl 122, had the great LOD value of 12.23, also explained 13.13% of phenotypic variation. It seems to be an important major QTL.Oil4-l located on chromosome 1 and linked to flanking markers, phi213984 and phi096, showed additive effect, explained 10.14% of phenotypic variation, which may also be a major QTL.4. Embryo oil concentrtion and the ratio of embryo weight to endosperm weight played a crucial role to kernel oil concentration, and explained 68.43% phenotypic variation. According to principle component analysis, embryo weight, embryo volume, 100-kernel weight and kernel volume also affected kernel oil concentration in some extent.