Patterns of physiologic diversity of Puccinia triticina on wheat in Indian subcontinent during 2008-2013

Brown (leaf) rust of wheat, caused by Puccinia triticina was widely distributed in all the wheat growing areas. To identify new pathotypes and determine the virulence pattern of Puccinia triticina, rust samples were analyzed from the wheat growing areas in India, Bangladesh, Bhutan and Nepal. A new pathotype 93R57 (104-4=NHKSP) was identified from Arki area of Solan district in Himachal Pradesh. Among the 37 pathotypes identified in 2124 samples analyzed during 2008-2013, four predominant pathotypes 121R63-1(77-5=THTTS), 21R55 (104-2=PHTTL), 121R60-1(77-9=MHTTS) and 21R63 (104-3=PHTKL) accounted for 68% of the population. These four pathotypes have virulence to Lr1, Lr3, Lr10, Lr11, Lr12, Lr13, Lr14a, Lr16, Lr17, Lr23, Lr26. Virulence on Lr19 was found in 7 samples only whereas the proportion of pathotype 121R60-1 (77-9=MHTTS) has increased recently in Tamil Nadu and was identified in about 40% of the samples from that area. Virulent pathotypes on Lr9, Lr24, Lr25, Lr32, Lr39 and Lr45 were not observed in the field population of brown rust in the Indian subcontinent during the last five cropping seasons