Novel broad range resistance sources against pan India isolates of Albugo candida causing white rust disease of oilseed Brassica

Abstract

Albugo candida, responsible for causing white rust disease, is a significant fungal pathogen leading to substantial yield and economic loss in Indian mustard. Therefore, it is necessary to explore intrinsic resistance in Brassica juncea germplasm for suppression of this disease. In the present study, phenotyping of exotic and indigenous collections of Brassica juncea was done against thirteen diverse A. candida isolates in cotyledon and true leaf plants under controlled conditions and in adult plants on field at different locations during three consecutive mustard crop seasons (2019–2022). Among 311 lines screened of B. juncea, 59 germplasms were found immune under artificial and field screening against various isolates of A. candida. Five accessions, EC766193, IC265495, EC766061, EC766595 and IC443623 of B. juncea were identified to express immune response for six of the pathogenic isolates, whereas, for rest of the isolates they expressed high to moderate resistance. Moreover, correlation study showed positively co-related resistance levels among adult plant and true leaf stage of development in B. juncea (r = 0.859, p< 0.01). The GGE biplot elucidated 69.4% of the total variation and visually displayed the resistance and stability for B. juncea accessions against white rust disease. These new sources of host resistance for virulent pathotypes of A. candida are critically important and will help to create a strong credential for discerning and mapping of resistance linked gene/QTL and to sustainably manage this disease in India.