First through fourth authors: Department of Biochemistry and Molecular Biology; fifth author: Department of Plant Pathology, L. A. Brinkerhoff is deceased; and sixth author: Department of Plant and Soil Sciences, Oklahoma State University, Stillwater 74078
The development and genetic characterization of four near-isogenic lines (NILs) of cotton (Gossypium hirsutum) is described herein. Each line contains a single, but different, gene for resistance to bacterial blight caused by Xanthomonas campestris pv. malvacearum. The lines were derived using at least six backcrosses to the susceptible recurrent parent ‘Acala 44’, followed by single plant-progeny row selection for uniformity. The NILs are homozygous for the B2, B4, BIn, or b7 genes and are designated as AcB2, AcB4, AcBIn, and Acb7, respectively. In the ‘Acala 44’ background, B2, B4, and BIn are partially dominant genes; b7 is partially recessive. Relative strengths of resistance conferred by those genes toward race 1 of the pathogen were B4˜b7>BIn˜B2. B4, BIn, and b7 each conferred resistance toward X. campestris pv. malvacearum carrying a single avirulence gene, whereas B2 was less specific.