Prevalence and distribution of Xanthomonas campestris pv. malvacearum races in Pakistan and their reaction to different cotton lines

Abstract

Bacterial blight of cotton caused by Xanthomonas campestris pv. malvacearum (Smith) Dye is a major disease in Pakistan. Four races of pathogen, race 18, 12, 10 and 8 are identified. Race 18 was found to be the most widely distributed race on upland cotton (Gossypium hirsutum L.). All the monogenic resistant cotton lines were attacked by race 18 alone or in combination with the other three races. The cotton lines containing blight resistant genes, B₂B₆, B₂B₃B₇, B₂B₃B₇ + BN and many other combinations remained immune to this disease under high levels of inoculum in Pakistan.