Evaluation of different Brassica genotypes under field conditions against white rust disease (Albugo candida) of rapeseed-mustard for resistant sources

Abstract

White rust or white blister disease caused by oomycete fungi, Albugo candia is one of the major devastating disease of rapeseed mustard. Continuous emergence of new races of the pathogen is responsible for breaking down of the resistance of already existing resistant cultivars. So there is need for the evaluation of existing resistant cultivars as well as new Brassica cultivars to find out stable resistance sources against the disease. In this context, 82 different Brassica genotypes, including 10 different Brassica species were evaluated in field, under natural conditions for the confirmation of resistance sources against Albugo candida in two successive years 2017-18 and 2018-19. Observations of percent disease severity and phenotypic disease reaction were taken at different time intervals of 70, 80 and 90 DAS. Infection rate and area under disease progress curve (AUDPC) were calculated for each genotype. Out of 82 Brassica genotypes evaluated, 26 were found free from the disease and 28 genotypes showed moderately resistant reaction while rest of the genotypes showed susceptible reaction at 90DAS. Minimum infection rate (0.0949) and AUDPC (69.44) was observed in DRMRJ 127 and SIVT-17-19 while maximum infection rate (0.1008) and AUDPC (588.0) was observed in 71 J0002 and RH 30, respectively at 90 DAS.