Differences. Closed Triangle Hybrid Groups To Detect Plant Height Qtl Alleles

The most important agricultural traits and economic traits of crop ,such as output, quality, breeding time are quantity traits. Different from quality traits, the quantity traits are controlled by many genes, so the hereditary foundation of quantity traits is complicated, and easy to be influenced by environment. As we know, the phenotype and genotype of quantity traits do not have clear corresponding relation. In the past, we can only infer the hereditary law of the quantity traits according to the average of the population.In recent years, with the development of biochemistry and molecular biology technology, especially the appearances of different molecular markers, it is possible for us to further study the hereditary foundation of quantity traits. Utilize the molecular marker, we can measure out QTL (QTL Mapping ). By din of QTL mapping, we can strengthen the ability of controlling the heredity of the quantity traits that improve the accuracy and foresight of chooseing the fine genotype of quantity traits in breedings. However, a lot of studies indicate that using different mapping population of the same species, even the same mapping population to locate QTL of the same quantity traits under different environmental conditions , the recapitulation of QTL was low.QTL spreads in the whole genome making the molecular marker assistant select difficult to implement in breeding. This text sketches basic principle and method of QTL mapping, utilize the example of plant height of maize to analyse why the recapitulation of QTL is low . At the end, it was proposed to locate QTL with closed triangle cross populations and detect allelic diversity of QTL. By this method, it was attempted to examine or raise the recapitulation of QTL location of the same quantitative trait with different mapping populations. The main result of study is as follows:(1)A genetic linkage map containing 104 SSR markers was constructed based on Huangzaosi×478, Which spanned 1883.8 cM and average distance is 18.1 cM. UsingF2.4 population of maize ,QTL affecting plant height were locating on chromosome 3, 4, 5, 6 and 8. with the composite interval mapping method. The function of the gene includes additive effects, partial dominance effects, dominance effects and overdomi-nance effects, rely mainly on additive effects and partial dominance effects. Ph3-1, Ph6-2 and Ph8 can explain 19.13%, 7.91% and 7.27% of the phenotypic variance. So we think they are the main QTL controlling plant height.(2) A genetic linkage map containing 93 SSR markers was constructed based on S37x478, Which spanned 1833.3 cM and average distance is 19.7 cM . Using F2:4 population of maize, QTL affecting plant height were locating on chromosome 3, 4, 6, 7, 8 and 9 with the composite interval mapping method. The function of the gene includes additive effects, partial dominance effects, dominance effects and overdominance effects, rely mainly on additive effects and partial dominance effects. Ph7 and Ph9-2 can explain 18.88% and 15.76% the phenotypic variance,so we think they are the main main QTL controlling plant height.(3) A genetic linkage map containing 87 SSR markers was constructed based on S37×HuangZaoSi, Which spanned 1739cM and average distance is 19.9 cM . Using F24 population of maize, QTL affecting plant heights were locating on chromosome 1, 2, 3, 4 and 9 with the composite interval mapping method. The function of the gene includes additive effects, partial dominance effects, dominance effects and overdominance effects, rely mainly on additive effects and partial dominance effects. Ph9-1 and Ph9-2 can explain 14.54% and 33.28% of the phenotypic variance. So we think they are the main QTL controlling plant height.(4) We can find relevant QTL at 3.05 bin of the third chromosome in "S37×Huangzaosi" " Huangzaosi ×478" and "S37×478". And the same time, the QTL of ph9-2 at 9.04 can be found in two population. At the end, it was proposed to locate QTL with closed triangle cross populations and detect allelic diversity of QTL. By this method, it was attempted to examine or raise the recapitulation of QTL location of the same quantitative trait with different mapping population.