Responsiveness of Albugo candida isolates causing white rust in different crucifers

To test the responsiveness of Albugo candida isolates causing white rust disease in Brassica juncea, nine different cruciferous hosts were cross-inoculated with five isolates of A. candida and one isolate of Wilsonia bliti collected from B. juncea and Amaranthus blitum, respectively. Isolate Ac-Dli was able to infect B. oleracea var. botrytis, B. oleracea var. capitata, and B. rapa subsp. rapa, while Ac-Mghy and Ac-Pnt were able to infect B. rapa subsp. rapa. Ac-Bgpt and Ac-Wltn isolates were able to cross infect B. oleracea var. capitata and B. oleracea var. gemmifera, respectively. Isolate of W. bliti from Amaranthus host was unable to establish a disease reaction to any of the cruciferous hosts due to the non-host nature of this species against the tested crucifers. Among the five A. candida isolates, Ac-Pnt was found to be the most virulent and Ac-Wltn to be the least virulent. Our study suggests the responsiveness of A. candida isolates from different geographical regions to other related cruciferous hosts which can act as an alternate host in the field condition. Therefore, the breeding strategies for the development of resistant varieties of B. juncea against white rust disease should also include other related cruciferous hosts wherever A. candida is reported pathogen. © 2021, Indian Phytopathological Society.