Yellow rust (Puccinia striiformis f. sp. tritici) and powdery mildew (Blumeria graminis tritici) of wheat can be effectively managed by the cultivation of resistant varieties. However, such resistant varieties become susceptible due to evolution and spread of new and matching virulences of these pathogens after a short period of their commercial cultivation. Hence, breeding for disease resistance tends to be a continuous process with prerequisite of identification of diverse resistant donors. In this context, more than 500 genotypes comprising advanced breeding material form CIMMYT and those developed in India were subjected to multilocational screening at hot spot locations of yellow rust and powdery mildew (Dhaulakuan, Malan and Ludhiana) under artificial epiphytotic conditions during the Rabi cropping season 2014-15 to 2016-17. Five genotypes from advanced Indian wheat breeding material were free from both the diseases whereas, 8 genotypes of CIMMYT origin showed mean terminal yellow rust (TYR) severity ≤5S and terminal powdery mildew (PM) reaction ≤3 and were highly resistant whereas 30 genotypes among Indian wheat breeding material showed mean terminal YR severity ≤5S and terminal PM reaction ≤5 were found resistant. Agronomically superior genotypes may be directly utilized as varieties and sources with multiple resistance may be used as donors in breeding program.

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Sources possessing multiple field resistance to bacterial stalk rot, banded leaf and sheath blight and maydis leaf blight of maize.

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The analysis of data on disease severity using genotype (G) and genotype by environment interaction (GGE) biplot revealed that the highest contribution to disease severity was due to genotype (G) 50.75 and 47.56 followed by G X E interaction 44.38; 37.70 and environment (E) 4.8 and 14.74 for powdery mildew (PM) and yellow rust (YR), respectively. Sixteen genotypes showing mean TDS ≤15% and Area under Disease Progress Curve (AUDPC), relative Area Under Disease Progress Curve (rAUDPC) and ‘r’ ranging between 20.63-494.44, 2.75-40.05 and 0.01-0.04, respectively in comparison with TDS, AUDPC, rAUDPC and ‘r’ of 41%, 1510.88, 99.18 and 0.04 respectively, in susceptible cultivar Lehmi, were slow mildewing genotypes. Six genotypes Maris dove, Rye, Aldan, CMH 77.308, SAW 71 and SAW 74 showed multiple resistances to PM and YR, of which ALDAN and CMH 77.308 were reported to be resistant to Karnal bunt (KB) also. Hence, these can be used as potential donors aimed to develop cultivars with combined resistance to PM, YR and /or KB and Kukumseri could be used as an ideal hot spot for screening against PM and YR.

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