This project continues and extends the development of intergenomic germplasm initiated under CSP4 7C. Under CSP4 7C, fertile synthetic hybrids that incorporate chromosomes from indigenous Gossypium species into cultivated cotton were developed, overcoming the fertility barrier. These new fertile hybrids include indigenous species that have gossypol-free seeds and possible resistance to Fusarium wilt Under that grant a variety of strategies for transferring genes from the native species were tested. In the end, a process called bexaploid bridging was identified as being the most likely to maximize the number of exchanges between the chromosomes of the indigenous Gossypium species and those of the cultivated cottons. This process involves repeatedly backcrossing the synthetic hybrids to cultivated cottons. Over several generations the chromosomes of the native species are progressively lost, but in the process some of their genes are left behind on the cultivated cotton chromosomes