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Genetics

Allelism Tests of Three Dominant Genes for Hypersensitive Resistance to Bacterial Spot of Pepper. A. M. Hibberd, Former graduate assistant, Vegetable Crops Department, University of Florida, Gainesville 32611, Present address: Queensland Department of Primary Industries, Box 327, Cleveland, Australia 4163; M. J. Bassett(2), and R. E. Stall(3). (2)Professor, Vegetable Crops Department, University of Florida, Gainesville 32611; (3)Professor, Plant Pathology Department, University of Florida, Gainesville 32611. Phytopathology 77:1304-1307. Accepted for publication 5 February 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-1304.

Three previously reported genes, Bs1, Bs2, and Bs3, for hypersensitive resistance to races of Xanthomonas campestris pv. vesicatoria were tested for allelism in four pepper (Capsicum annuum) crosses involving the parents 271-4, Delray Bell, Florida XVR 3-25, Early Calwonder, and Early Calwonder 10 R. Breeding line 271-4, which is resistant to both races 1 and 2, was a selection from PI 271322, and Early Calwonder 10 R is near-isogenic with Early Calwonder but carries resistance gene Bs1. Bacterial suspensions of 5 × 10⁸ cfu/ml of races 1 and 2 were infiltrated into leaf mesophyll. Hypersensitive resistance was assessed 24 hr after infiltration. Segregation in progenies from four crosses, 271-4 × Delray Bell, 271-4 × Florida XVR 3-25, 271-4 × Early Calwonder, and 10 R × XVR 3-25, indicated that the dominant genes Bs1, Bs2, and Bs3 are independent. It was also indicated that Bs2 controls hypersensitive resistance to both races 1 and 2 and that the resistance genotype of 271-4 was Bs1 bs2 Bs3. The resistance genotypes were confirmed to be Bs1 Bs2 bs3 for Florida XVR 3-25 and Bs1 bs2 bs3 for both Delray Bell and 10 R.