Pathotypic evolution in Puccinia striiformis in India during 1995 - 2004

Yellow rust pathogen (Puccinia striiformis) distribution was monitored in different wheat-production zones (north-western plains zone, north hills zone, and south hills zone) of India during the last decade (1994–2004). Studies indicated the predominance of 3 pathotypes: 46S102 (46E149), 47S103 (47E148), and 46S119 (46E149+Yr9) in the north-western plains zone. These pathotypes were detected for the first time in 1995–96 and are evolving frequently. Another pathotype (78S84), although present in low frequency, was first detected from northern India and is virulent on Yr9 and Yr27, posing a major threat to cv. PBW343, which carries these genes. The high altitudes of the northern hills where very primitive wheat cultivars are grown showed less variability for the yellow rust pathogen. Continued breeding efforts and replacement of cultivars have resulted in low specialisation in the yellow rust pathogen in the south hills zone and pathotype 38S102 predominated in this area during the last decade.