HIGH RESOLUTION MAPPING OF FERTILITY RESTORERGENES FOR CYTOPLASMIC MALE STERILITY IN COTTON

摘要

In cytoplasmic male sterility (CMS)-based hybrid cotton breeding and genetics, the construction and utilization of a highresolution linkage map can facilitate marker-assisted selection for restorer lines and allow for greater precision in the isolationof the fertility restorer genes. The objectives of this research were to develop a high resolution linkage map for fertilityrestorer genes of cotton using various PCR-based DNA markers. B418 (D2-2, Rf1) possessing male sterile cytoplasm (D2-2) andcorresponding fertility restorer gene (Rf1), was used as female to cross with D8R3 (D8, Rf2) possessing male sterile cytoplasm(D8) and corresponding fertility restorer gene (Rf2). The resulting F1 was testcrossed as female with Suregrow 747 containingnormal fertile cytoplasm and no fertility restorer gene. The testcross population (TC1F1) was grown in 2002/2003 winter inthe greenhouse for male fertility evaluation and DNA marker analysis. The mature bolls from the heterozygous restored fertileplants were bulk harvested and grown as TC1F2 (equivalent to F2) in the field in Las Cruces, NM in 2003. Segregationanalysis of male fertility in the TC1F1 confirmed involvement of the Rf1 gene in controlling fertility restoration in the CMScaused by D2-2 cytoplasm, while the Rf2 gene did not promote male fertility restoration in this system. No distortion of segregationin fertility (786 fertile vs. 246 sterile) was noted in the TC1F2 population. Bulked segregant analysis was used to identifyadditional molecular markers (SSR, RAPD, and STS) linked with the fertility restorer genes. Two of the five previouslydeveloped STS markers successfully discriminated fertile plants from sterile plants. So far, 28 SSR primer pairs werescreened using two isogenic lines, which produced 5 potential polymorphic SSR markers.