Cotton Is The Excavation And Positioning Of Wild Species G.klotzschianum Of Genome Introgression Of High-quality Fiber Gene

Cotton is an important cash crop in the world.Cotton. cotton fiber is one sort of natural fiber which is the important material for spinning. In the recent years,improvement of cotton fiber quality has been extremely important because of changes in spinning technology and the needs of the people. The most Chinese cotton varieties are almost of low qualityand sensitive to cyanosis. As we know, the genes contributed to high fiber qulity mainly comes from the American Acala S J series and PD lines. However, the negative correlation between yield and fiber quality are still presented even after over dozens years of exhausting breeding for improving fiber properties due to the genetic complexity of fiber quality properties. Conventional breeding had great difficulty in further improving fiber quality because of its high costs, long periods and low selective efficiency. So it is important to mine the genes associated with high quality fiber with effective methods.There are 51 cotton species, including 4 cultivated species and 47 wild species.The wild species embody considerable genetic diversity, such as pest-resistant, disease-resistant and fine fiber quality. In dozens of years, by interspecific hybridization, the elite gene of the many wild relatives of the cultivated cottons have been introgressed into the upland cotton. With the advent of modern molecular biology, we can mine the elite gene effectively from wild species, enhance new germplasms and broad genetice diversity of upland cotton.In this study, a backcross population (BC1F2) between G.klotzschianum and G.hirsutum(86-1) was constructed. About 500 SSR markers covered cotton genome were selected to trace introgression segments . Single marker analysis and composite interval mapping were employed to detect QTLs associated with fiber qulity traits. 1 Totally, 21 introgression fragments from G.klotzschianum were identified under G.hirsutum (86-1) background on 16 chromosomes. The length of introgression fragments was 717.81cM, which accounted for 14.3% of the cotton genome.2 A genetic linkage map of chromosome 13 was constructed by Mapmaker3.0, which contained 5 markers (BNL1421,NAU1023,NAU1201,NAU1141 and BNL2652) and 2 phenotypic traits (yellow petal color-Y1 and open bud-ob2). The length of the linkage was 69.6cM.Y1 was controlled by one dominant gene, ob2 by one recessive gene.3. Single marker analysis using SAS program was applied to detect the correlation between the markers and the fiber characters. Fifteen markers showed significant correlation with fiber quality, 4 of which associated with fiber length ,7 with fiber strength and 4 with fiber micronaires. Three QTLs for fiber quality were detected on chromosome 13 by WinQTL cartographer 2.0. fiber length QTL accouted for 30.76% phenotype variance, fiber strength QTL for 3.64% and micronaire QTL for 21.92%.