Increasing Marker Density Of Genetic Map From A Recombinant Inbred Line Population In Upland Cotton

Cotton as the cash crops all over the world is the most important natural textile fiber crop. With advances in science and technology, the textile industry began to introduce a rapid and efficient spinning technology, such as air-jet spinning and air spinning. It is a great challenge to plant breeders that most consumers have high requirements on the quality of cotton.The fiber quanlity and yield of cotton belong to quantitative traits, and significant negative correlation exists between the cotton fiber quality and yield traits. The low efficiency of traditional selection breeding method can not meet the demand of cotton market. With the development of modern DNA marker technology, breeders find a fast, accurate and efficient selection method. The maker tightly-linked with quantitative trait locus (QTL) controlling fiber quantitative traits could be identified according to the high-density linkage map, which would be of great importance for breeders to improve breeding efficiency.The present study used new SSR primers including PGML from Gossypium raimondii and S WU from RFLP probe to increase the maker density of genetic map from a recombinant inbred line population (CCRI35×Yumian1). The result will pave a way for mapping and map based-cloning QTL controlling fiber quality and yield traits in cotton. The main results were as following:1. Primer polymorpHismIn this study,5000PGML and363SWU primer pairs were used to screen the polymorpHism between CCRI35and Yumian1, and182PGML primer pairs and11SWU primer pairs showed polymorpHism, accounting for3.6%and3.7%of total primers. Together with the primers obtained in our laboratory,921of19892SSR primer pairs showed polymorpHism. accounting for4.6%of total primers.2. Genotyping recombinant inbred linesThe182PGML and11SWU polymorpHism primers were used to genotype the180lines from recombinant inbred line population (CCRI35XYumian1), and196PGML and11SWU maker loci were obtained, respectively. Up to now.935loci were obtained in recombinant inbred line population (CCRI35×Yumian1). Among the935loci,687segregated as co-dominant marker (73.5%) and248as dominant marker (26.5%). The935loci were conducted onx-testing analysis, and358loci deviated from the1:1Mendelian segregation ratio (P<0.05).3. Genetic linkage analysisThe196PGML loci and11SWU loci, together with728loci previously obtained in our laboratory, were used to conduct on genetic linkage analysis, and a linkage map with872marker loci and78groups was constructed. The map covered a length of3487cM and the average distance between tow makers was4.0cM. The map contained278deviated loci (P<0.05).