Construction Of High Density Genetic Map For Interspecific Population Gossypium Hirsutum × Gossypium Barbadense

Cotton is not only the most important provider of natural fiber, but also the main source of oil and protein. Today the development of technology and the improvement of people’s living standards have brought higher standards for yield and fiber quality in cotton breeding. Improving fiber quality and increasing yield as soon as possible at the same time has become a great concern for cotton breeders. However, traditional breeding method based on phenotype selection requires long working time can not make breakthroughs in cotton breeding. With The advancement of bioliogy, marker assisted slection provides a rapid and precise approach for crop breeding.Gossypium include 45 diploid species and 7 tetraploid species. Tetraploid upland cotton(G. hirsutum L.) and sea-island cotton(G. barbadense L.) cover around 95% and 2% of the whole production of cotton around the world. Gossypium hirsutum has wide adaptability and high yield but poor fiber quality. Gossypium barbadense has super fiber quality and resistance to verticillium wilt but low yield. Constructing a high density genetic map of Gossypium hirsutum × Gossypium barbadense interspecific population is of great significance in studying genome structure, fine mapping and map-based cloning QTL for important agronomy traits.Based the previous work in our laboratory, the present study used new SSR makers to increase the maker density of genetic map from an intraspecific population(G. hirsutum cv. CCRI 35 × G. barbadense cv. Pima S-7). The main results were as following: 1. Primer polymorphismA total of 7024 of SSR primer pairs were used to screen the polymorphic primers between upland cotton cultivar CCRI35 and sea-island cotton cultivar Pima S-7 and 978 polymorphic primer pairs were obtained, accounting for 13.9% of total primers. 2. Genotyping BC1 populationThe polymorphic primer pairs were used to genotype [(CCRI 35 × PimaS-7) × CCRI 35] BC1 population and 1071 loci were obtained. The 2312 loci, together the loci previously obtained in our laboratory, were conducted on χ2 testing. The result showed that 204 loci deviated from the 1:1 Mendelian segregation ratio(P<0.05), accouting for 8.8% of the whole loci. 3. Construction of high density genetic mapGenetic linkage analysis is applied to the 2312 loci, and a linkage map with 26 groups was constructed. The length of map coverd 3804.6cM and the average distance between markers were 1.65 cM. A total of 1121 loci were mapped on At subgonome whcich covered 1898.7 cM, whereas 1191 loci were mapped Dt subgenome which covered 1905.9 cM.This research according to the distribution of repeat locus on homologous chromosomes found four of homologous chromosomes happened chromosome structure inversions.