Resistance of Interspecific Cotton Hybrids (Gossypium hirsutum × G. barbadense Containing G. harknessii Cytoplasm) to Fusarium Wilt. D. Netzer, Agricultural Research Organization (ARO), 50 250 Bet Dagan. Y. Tal, Hazera Seed Company, Mivhor Farm; A. Marani, Hebrew University of Jerusalem, Faculty of Agriculture, Rehovot; and C. Weintall, ARO, Bet Dagan, Israel. Plant Dis. 69:312-313. Accepted for publication 10 September 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-312.

Analysis of progenies of crosses between the resistant cultivar Acala SJ-2 (G. hirsutum) and the susceptible cultivar Pima S-5 (G. barbadense) indicated that resistance to race 3 of Fusarium oxysporum f. sp. vasinfectum is controlled by a dominant gene. Crosses between breeding lines—male restorer and female (male sterile) parents, both on a background of G. harknessii cytoplasm—indicated that the resistance is not affected by the cytoplasm of the latter species. All but one of the five restorer lines tested with the G. barbadense genome were found susceptible to the fungus. Thus a close linkage of genes conferring resistance and restoration of fertility is ruled out. In addition, the resistance of such a restorer line enables us to obtain intraspecific as well as interspecific hybrids of cotton resistant to race 3 of the fungus.