Shifting in Virulence of wheat leaf rust causal agent in Baghdad region
Authors: M.A. AL-Hamdany, H. A. Abas and A. H. Kadhem
Citation: 2002. Iraqi J. Agric. 7(5): 9-17.
As a result of wheat leaf rust epidemic form during 2000-2001 season in middle region of Iraq, remarkable shift in the virulence pattern of Puccinia recondita f. sp. tritici was observed. In contrary to virulence pattern recorded in 1997 and 1998 seasons, the causal agent overcame the resistance genes Lr22, Lr 24, and unknown Lr genes carried on K 4500.2 Bjy (M10). Meantime, both Lr15 and Lr 17 are still effective (1R and 5R respectively).Therefore, the new avirulent/virulent formula for P. recondita f. sp. tritici in Baghdad region could be Lr15,17/1,2a,2b,2c,3,9,10,11,12,13,14a,14b,18,19,20,22,30,B,Exch.1+, and C. However, many unknown resistant genes carried on the following wheat genotypes, (Tob D Man X Db/AdI) Sx (M1), ktn M12 Up 30 301/D Man 7C X AdI (M3), Pasula S (M4), Maya S Mon S (M5), Chiroca-Amahnae (M8), HD 2205-A1d S (M11) and Clement-Mo 73 X Torim 73 (M12) proved to be effective. The epidemic form of wheat leaf rust was fully reflected on most Iraqi wheat cultivars. The host reactions of these cultivars ranged from moderate susceptible to susceptible reactions except Noor cultivar.
Key Words: Wheat leaf rust, Lr resistant genes, Avirulenr/Virulent formula