Identification of new source of resistance against white rust

Abstract

Mustard is one of the most important oilseed crops in India in general and in the Rajasthan in particular. Low yield in
mustard is attributed to many biotic and abiotic stresses. White rust, a serious foliar disease caused by Albugo candida
is one of the major threats responsible for significant reduction in yield (17-55 %). Among various management approaches,
use of resistant varieties is considered best, as it is cost-effective and environment friendly. However, till now only few
resistant sources against this disease have been reported. Therefore, in the present investigation, 34 rapeseed-mustard
germplasms were evaluated in natural field conditions during 2019-20 and 2020-21 to identify sources of resistance. Out
of 34, only one accessions (IC422166) showed immune reaction (0) whereas other accessions showed variable reactions
ranging from resistant (1-3) to highly susceptible (>6) against white rust. The identified accession remained stable for
disease immunity under artificial inoculation with environment-controlled conditions against different isolates of A.
candida from mustard growing regions. Therefore, identified accession may have potential of utilizing as resistant
donor in the crop improvement programme for developing resistant cultivars having good agronomic traits and highly
productive genetic potential and also for mapping and tagging resistant gene against white rust.