Document Type : Original Article
Authors
1
Plant Pathol. Dept., Fac. Agric., Cairo University
2
Wheat Dis. Dept. Plant Pathol. Res. Inst., A.R.C., Giza, Egypt
Abstract
Wheat leaf rust is the most widespread and regularly occurring disease of wheat in Egypt and worldwide. Collections of Puccinia triticina were obtained from rust-infected wheat leaves (Triticum aestivum) surveys from wheat fields and Egyptian wheat rust trap nursery EWRTN in Damietta, Monufiya, Qalubiya, Suez and Beni-Suef governorates in order to determine the virulence dynamics of wheat leaf rust population in 2009/10 and 2010/11. The virulent phenotypes were tested on a set of 16 lines of Thatcher wheat that are near-isogenic for leaf rust resistance genes, i.e. Lr1, Lr2a, Lr2c, Lr3,
Lr9, Lr16, Lr24, Lr26, Lr3ka, Lr11, Lr17, Lr30, Lr10, Lr18, Lr21, and Lr2b. Out of 102 and 33 virulent phenotypes that were identified, TKTT (12.8%), TTTT (8.1%) and KKTT (3.4%) were the most common pathotypes in 2009/10. While MKKS (11.5%), and BBBB (8.2%), PSSS (8.2%) were the most common pathotypes in 2010/11. Furthermore, the lowest virulence frequencies were found for genes; Lr25 (15.08%), Lr19 (16.87%), Lr9 (22.34%), Lr28 (30.16%) and Lr29 (32.96%). While, Lr's 2c, 3ka, 10, 18, 16,30 and 24 had the highest frequencies of virulence; 86.03, 85.47, 84.35, 83.79 , 82.68%, 82.68% and 82.12% , respectively in 2009/10. The lowest virulence frequencies for leaf rust resistance genes occurred with Lr19 (14.59%), Lr2a, Lr28 & Lr42 (each with 17.54%), Lr9 (20.35%), Lr2b (22.80%), Lr36 (26.31%), Lr25 (28.07%) and Lr45 (29.82%). However, high virulence was recorded with Lr's; 1, 35, 10, 15 and 18 (100.0, 80.7, 78.94, 75.43 and 73.68%, respectively) during 2010/11.
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