| Indica (O. Sativa ssp. Indica) rice and Japonica rice (O. Sativa ssp. Japonica) are two cultivated rice subspecies. These subspecies have a high degree of genetic differentiation. Understanding the genetic background of Indica and japonica rice genetic characteristics, mining affects quality and agronomic trait gene, for Indica-Japonica fine gene transfer and utilization of heterosis has very important significance in theory and practice.Constructing chromosome segment substitution lines is an effective method to shift agronomic characters of the two subspecies, it plays an important role in improving varieties of excellent characteristics, analysis of quantitative traits, QTL mapping and cloning. Chromosome segment substitution lines is a stable, permanent separation of groups, is the use of backcross, selfing and molecular marker assisted selection method resume near-isogenic combination. On the basis of this, In this experiment Temnykh and McCouch construction of high density molecular marker genetic map based. Using the Chang Huil21and the more light the two parental, from SSR molecular marker selection has polymorphic primers, and integration has been selected with polymorphic SSR markers, after two backcross generations, then the selection, we get the following conclusions:(1) Based on the genetic map, selected430pairs SSR primers homogeneously distributed on12chromosomes of rice from public databases430pairs of SSR markers, on Changhui121and Koshihikari for two parent polymorphism detection,232primers were obtained with parental polymorphism, the polymorphic rate was53.95%. According to the published genetic map, choose93markers which distributed relatively uniformly on the12chromosomes, with reference to their genetic distance, construct the molecular linkage map. The maps covering1428.5cM of the whole genome, and average distance between markers is15.3cM.(2) Using the above93SSR molecular markers with polymorphisms for two BC2F1group, which each other as the background of parent,100strains use the Changhui121as the background,68strains use the Koshihikari as the background, SSR testing, with GGT software mapping, on two sets of molecular markers in a group a single plant on the genotype of the belt type analysis of results:background parent with type basically has reached80%, heterozygous phenotype molecular markers were in20%or so. Using heterozygous parents as selection criteria,31strains use Changhui121as background and30strains use Koshihikari as background were selected as the candidate strains for the construction of chromosome segment substitution lines.(3) Making a genome-wide detection for the36strains using Changhui121as background and30strains using Koshihikari as background, and through GGT software mapping, analysis of two sets of groups of replacement heterozygous fragments, results were as follows:using Changhui121as the background of the chromosome segment substitution lines group heterozygous replacement fragments with a total of47, its total length is1752cM, longer than the total length of the rice genome by nearly20%, with an average length of38.11cM; using Koshihikari as the background of the chromosome segment substitution lines group heterozygous replacement fragments with a total of38, its total length is1681.5cM, equivalent tol.1times of the total length of the rice genome. Its average length is46.6cM. The genome-wide coverage of the two set of groups of replacement of the heterozygous fragment are93.28%.Although the two sets of chromosome segment substitution group materials are still not perfect, it has screened have laid the foundation for the construction of a comprehensive and accurate CSSLs. This provides new germplasm resources for the use of the good taste quality of Koshihikari and high yield, quality, good combining ability of Changhui121in the future. This also provide certain molecular mechanism for its precise QTL positioning as well as directly using on breeding in the future. |
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