Population Structure for G. barbadense L. Chromosome Fragment Introgression with G. hirsutum L. through Random Mating

Gossypium barbadense L. has significantly better fiber quality than upland cotton G. hirsutum L.  However, introgression barriers limit traditional breeding approaches to introgress alleles into upland cotton.  The development of chromosome substitution lines from G. barbadense (CS-B) opens a door for more efficient introgression of alleles from G. barbadnese into upland. Eighteen chromosome (or arm) substitution lines were crossed to three elite cultivars SG747, PSC355, and FM966, and random mating began with the F1 generation.  The initial random making cycle was called C0, and then four more random making cycles were implemented, which results in a C4S1 population developed after one generation of selfing.  We used 469 chromosome-specific SSR markers to conduct genotyping via protocol on ABI Genetic Analyzer 3130xl. After five random making cycles, all target G. barbadense chromosome fragments of these CS-B lines are all present in the C4S1 populations. All C4S1 plants contain at least three G. barbadense chromosome fragments, which indicated a great potential for introgression of G. barbadense alleles into the excellent G. hirsutum agronomic background. The result demonstrates a valuable pathway for introgression of exotic germplasm with useful genes into Upland cotton by using CS-B as a genetic bridge. A consensus genetic map was used to demonstrate the fragment distribution regions that were introgressed.