Virulence genes of puccinia recondita f. Sp. Tritici, the causal agent of wheat leaf rust in some regions of iran during 1995-1999

To determine virulence factors of Puccini recondite f. sp. trifici on wheat and their annual changes, trap nurseries were grown annually during a period between 1995 to 1999 in Sari, Kermanshah, Moghan, Zabol, Ahvaz, Shiraz and Ardebil, where leaf rust often occurs. Nurseries consisted of 28 near - isogenic lines, each containing a single Lr resistance gene. The nurseries were grown under natural infection and mist irrigation system, to provide suitable conditions for disease development. Susceptible check cultivar were included in the nurseries for even more development and distribution of leaf ruct on plants. At adult plant stage, infection types and disease severity on all entries were recorded at least for three times. Infection types O, R, MR and MS were considered as Avirulence and type S as Virulence for interpretation of presence or absence of virulence factors for resistance genes. According to the results, in 1995, there was virulence for genes Lr1, 2a, Ech, 2c, 2b, 3, 3Ka, bg, 9, 11, 12, 13, 15, 17, 18,21, 22b, B. In 1996 virulence appeared for Lr1, 2a,Ech, 2b, 3, 3bg, 3Ka, 9, 12, 13, 14b, 15, 16,17,18,21,22,23,24,30,34. In 1997 the disease appeared only on some cultivars in a few regions. In this year virulence observed only for Lr1, 2a, 2b, 2c, 3, 3Ka, 10, 11, 12, 13, 15, 30,34. In 1998 disease appeared only in few locations, and resistance gene Lr1, 2a, 2b, 2c, 3Ka, 10, 11, 12, 13, 15,21,30 were affected. In 1999 for Lr2b, B, 15 in Sari and for Lr1, 2a, 2b, 2c, 3, 3Ka, 9, 10, 14a, 16,24, 30 in Ahvaz virulence factors were observed.