Wheat rust status and its implications in Pakistan

Detailed rust surveillance of wheat growing areas in Pakistan was conducted from 2011 to 2014. Information about varietal distribution, growth stage, and rust incidence and severity was collected at 950 locations, and rust samples collected from these locations were subjected to race analysis. Yellow rust showed increasing incidence of high to moderate severity. Commercial cultivars released during 1991 to 2011 showed MS to S reactions. Twenty eight races were identified, most with wide virulence ranges. The frequencies of virulence to Yr1, Yr6, Yr7, Yr8, Yr9, Yr17, Yr27, Yr43, Yr44 and YrExp2 all exceeded 50%. Leaf rust also showed increasing incidence, mainly due to cultivation of the susceptible cv. Sehr-06. Fourteen races were identified. The frequencies of virulence to Lr1, Lr2c, Lr3a, Lr16, Lr26, Lr3c, Lr17a, Lr30, LrB, Lr10, Lr14a, Lr14b and Lr21 exceeded 50%. Virulences to Lr2, Lr9, Lr24, Lr18 and Lr19 were not detected and frequencies of virulence to Lr11 and Lr20 were low. Current and old commercial cultivars showed MS to S reactions. In 2011 and 2014 stem rust incidence was sporadic, but in 2013 it was present at 33 of 232 locations in Sindh, Punjab, Khyber Pakhtunkhwa and Baluchistan. Race RRTTF was identified in all samples.