Identification of slow stripe rusting wheat genotypes
Stripe or yellow rust is a constraint to wheat production on about 12.8 m ha in the Northern Hills and North Western regions of India. Varieties resistant at the time of release become susceptible usually within a few years due to new pathogen races. The present study conducted in 2013-14 was undertaken to identify slow stripe rusting genotypes among a panel of 192 advanced breeding lines and popular cultivars. All genotypes were planted in two replications and a susceptible control was planted after every 20 plots. The nursery, grown at Karnal, was inoculated with a mixture of prevalent Pst races 78S84 and 46S119. Genotypes were categorized into distinct groups based on area under disease progress curve (AUDPC) values, viz. 22 lines with AUDPC values 1-100, 18 lines with values 101-200, 43 lines with values 201-500, and remaining lines with higher values. Apart from rust-free lines assumed to carry all-stage resistance genes, lines with AUDPC values of less than 500 and having AUDPC values <20% of those of the susceptible check (maximum AUDPC value, 2500) were considered to be slow rusting. Some of the popular cultivars (HS 507, HS 542, WH 1105, HD 3086, DPW 621-50, HD 3059) currently grown in northern India showed slow rusting. The information generated can be utilized in improving the levels of stripe rust resistance in current cultivars.