An in vitro approach to identify sources of resistance to Fusarium wilt caused by \u3ci\u3eFusarium oxysporum\u3c/i\u3e f. sp. \u3ci\u3evasinfectum\u3c/i\u3e race 4 in domesticated cotton

Cotton lint produced by the plants Gossypium barbadense L. (pima cotton) and Gossypium hirsutum L. (upland cotton) is the world’s leading source of renewable textiles. The fibers of the cotton plant have been woven so intricately into our society that it would be hard to imagine life without their products. Cotton breeders must then not only continue to work to improve the quality of cotton fibers (fineness, strength, dyability, etc.) but also to improve the resilience of the plant against biotic and abiotic factors. Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) is an aggressive fungal pathogen, which causes Fusarium wilt, that presents a serious threat to cotton production in the US. Fifteen years of genetic research on and breeding for FOV4 resistance in upland cotton has failed to achieve meaningful results, nor deliver highly resistant upland cotton lines with durable genetic resistance. In this thesis, I briefly discuss the history and biology of the cotton plant, Fusarium wilts in cotton agriculture, and the development of techniques for FOV4 pathogenicity screening. I then present a study on the development and validation of an in vitro FOV4 co-culture screening tool that enables discreet studies on host/pathogen interaction, allows for complete environmental control, and facilitates rapid results. Lastly, I discuss how this research fits into advances in current FOV4 resistance breeding programs and the future research that can build on this study