Development Of The Cotton SSCP Markers And QTL Location Of Yield And Fiber Quality

Upland cotton and sea-island cotton are the main cultivated species and provides more than95%and2%of total production in the world. Upland cotton has the character of high yield and strong adaptability to environment, sea-island has the character of excellent fiber quality, and how to transfer high quality gene of sea-island to upland cotton cultivated species,, and breed cotton varieties with high quality and yield is the important goal of cotton breeding at present. In the genome, the SNP site generally exits, and the genome has a base variation every1kb, so the SNP marker will have significant influence in the construction of cotton linkage map and research of MAS.Single strand conformation polymorphism (SSCP) is a new technology for the analysis of molecular marker, and which can detect the variation of the single nucleotide, so it is used to detection SNP. SSCP has the character of rich polymorphism, strong genetic stability and high density, and it can greatly enrich the cotton molecular marker. In this study, we use the contigs of gene related to fiber development for primers designing, and develop SSCP molecular markers. Then we use the high backcross inbred lines of sea-island cotton and upland cotton to construct linkage map, and mine QTLs of important agronomic trait, and lay the foundation for fine map and marker assisted seltction. The followings are the main progress in our study:1.137pairs of SSCP primers were designed from gene related to fiber development, and64pairs of which were detected polymorphism in the eight material. We sequenced the polymorphism band of part of SSCP primers, and the result indicate that the target segment of PCR amplification exits SNP sites.2.255pairs of SSCP primers were applied for polymorphism screening in the parents and the population, Finally, The72pairs of SSCP primers were detected polymorphism in the population and a total of103molecular markers were received.3. Total579molecular markers were used to construct genetic linkage map using the mapping soft ware (Jionmap4.0). the genetic linkage map contains409molecular markers,2054.33cM of genetic distance and5.02cM of mean distance.. In the103SSCP markers,57markers enter into the linkage group,18of which were positioned the chromosome.4. While the composite interval mapping (CIM) of WinQTLCart2.5software was used for QTL location analysis of lint percent/boll weight/seed cotton yield/lint cotton yield/fiber length/fiber uniformity/fiber elongation/micronaire/fiber strength. A total of81 QTLs were obtained in four environments. There are35QTLs related to fiber yield, The other46QTLs are related to fiber quality.5. The6QTLs (qFL28-1, qFL-34-1, qFM-52-2, qFM-52-3, qFE-4-1, qFS-56-1) were detected in two environments, and they are related to fiber quality. There are4QTLs: qFM-52-1, qFM-52-3, qFE-4-1, qFS-56-1not only explaining more than12%of phenotypic variance, but also detected in different environments, so they can be used for further research.6. Get eight SSCP marker connected five QTL. ANN3-3is closely connected to qBW-22-1. ANN8-2、DGAT4-1and DGAT11-1are closely connected to qFU-24-1. G11-24is closely connected to qFU-29-1. PEPC5-1is closely connected to qFE-29-1. ANN1-3and ANN1-4are closely connected to qBW-40-1.