Variability in wheat yield under yellow rust pressure in Pakistan
Wheat yield of 37 wheat varieties along with a susceptible check, Morocco, was studied under yellow rust pressure across 3 locations of North West Frontier Province (NWFP), Pakistan during 2007. Considerable high disease pressure, as revealed by yellow rust severity, was observed at all locations with the maximum (100%) at Cereal Crop Research Institute (CCRI), Nowshera. Disease severity ranged from 0% to 70% for the tested varieties while reached 100% for Morocco with S type of host response. We report the presence of sufficient variability across locations for both yield potential and yellow rust severity. Locations with maximum disease pressure had lower mean grain yield and vice versa. NIFA followed by AUP had higher mean grain yield (5533 kg ha-1 and 4292 kg ha-1, respectively) with lower maximum disease severity values (70% and 80%, respectively). CCRI had higher disease pressure (100% severity for Morocco) with lower mean grain yield (3676 kg ha-1). Bahawalpur-95, Suleman-96, Kohsar-93, Fakhre-Sarhad, Tatara, and Frontana had relatively stable severity across locations in a range of 0% to 10%. Based on overall traits, Kohsar-93, Bakhtawar-92, Saleem-2000, Fakhre-Sarhad, Tatara, and Karwan had better yield and lower yellow rust severity and is recommended for cultivation and further breeding exploitation.
Key words: Puccinia striiformis, wheat varieties, multi-locations, yield variability