Stripe rust resistance in Indian wheat cultivars and advance lines
In India, wheat crop is a major contributor to the agricultural economy of India, occupying 30.7 mha area with 98.38 mt production. Stripe or yellow rust is a constraint to wheat production on about 12.0 m ha in the Northern Hills and North Western region 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 2015-16 was undertaken to identify stripe rust resistant genotypes among a set of 146 advanced breeding lines and popular cultivars. All genotypes were planted in two replications in northern India at ten locations viz., Karnal, Hisar (Haryana), Ludhiana, Gurdaspur (Punjab), Malan, Bajoura, Dhaulakuan (Himachal Pradesh), Pantnagar (Uttarakhand), Durgapura (Rajasthan), Jammu (J & K) and Delhi. After every 20 genotypes, infector (susceptible cultivar to both pathotypes) was planted. All genotypes were inoculated with mixture of prevalent Pst races 78S84 (Yr 27 virulence) and 46S119 (Yr 9 virulence) at Karnal. Out of 58 released cultivars grown in different zones of the country, fifteen lines (HS 507, DBW 90, HD 3086, WH 1080, WH 1124, WH 1142, HD 4728, HI 8498, HI 8737, MPO 1215 (D), NIDW 295 (d), UAS 428 (D), UAS 446 (D), DBW 71, KRL 210) showed stripe rust ACI < 10.00 (average coefficient of infection). But among advance 88 wheat lines, there was good level of resistance in 50 lines (ACI <10.00). Lines having AUDPC values <20% of those of the susceptible checks (maximum AUDPC value 2500 on susceptible check) were considered to be slow rusters. In present study, some of the wheat varieties (DBW 93, HS 490, PBW 723, PBW 644, VL 829, VL 892, WH 1105, WR 544 ) grown at present in northern India were identified as slow ruster lines. The information generated can be utilized in improving the stripe rust resistance of popular cultivars.