Significant contributions in the development of Verticillium wilt resistant cotton germplasm have been made by the USDA Cotton Research Station, at Shafter, CA. Efforts to breed wilt resistance into California acalas began as early as the 1930's, and this effort has remained a high priority in recent acala breeding programs. John Turner began developing his 1-2302 germplasm in the 1950's and from this was derived the Acala varieties SJ-1 and SJ-2. As successful as these acalas were, San Joaquin Valley (SJV) cotton growers required still greater levels of wilt resistance. H.B. Cooper made additional contributions during the late 1960's in the development of the wilt resistant Acalas SJ-3, SJ-4, and SJ-5. All these SJV acala varieties have been the result of an infusion of highly wilt resistant New Mexico germplasm into the California acala breeding program.