ESTABLISHMENT OF MOLECULAR MARKERS AND LINKAGE GROUPS IN 2 F2 POPULATIONS OF UPLAND COTTON

Two F-2 populations of cotton (Gossypium hirsutum L.) from the crosses of HS46 x MAR-CABUCAG8US-1-88 (MAR) and HS46 x Pee Dee 5363 (PD5363) were characterized for restriction fragment length polymorphisms (RFLP s) using DNA probes. Seventy-three probe/enzyme combinations were used in the HS46 x MAR population analysis, which resulted in 42 informati ve polymorphic fragments. These 42 moleclar markers represented 26 pol ymorphic loci, which consisted of 15 codominant and 11 dominant (+/-) genotypes, Chi-square analyses of these loci fit expected genotypic ra tios of 1:2:1 and 3:1, respectively, An analysis of these loci with th e MAPMAKER program resulted in the establishment of four linkage group s A, B, C, and D with 4, 2, 2, and 2 loci, respectively, as well as 16 unlinked loci. Six probe-enzyme combinations were assayed on the HS46 x PD5363 population, which resulted in 11 informative polymorphic fra gments. These 11 fragments represented 6 polymorphic loci, 1 dominant (+/-) and 5 codominant genotypes, The MAPMAKER analysis of these loci yielded 2 linked loci. Thus, a total of 53 polymorphic fragments and 3 2 polymorphic loci, representing five linkage groups, were identified among the two families.