Yellow Rust Resistance in Advanced Lines and Commercial Cultivars of Bread Wheat from Ethiopia

Abstract

Bread wheat (Triticum aestivum L.) cultivars often succumb to yellow rust (Puccinia striiformis f.sp. tritici Westend.) soon after their release for commercial production, especially in the highlands of south-eastern Ethiopia. Variety diversification may buffer the ever evolving new races of the yellow rust pathogen. The objective of this study was to characterize seedling yellow rust resistance in 21 advanced bread wheat lines and 20 cultivars from Ethiopia. Yellow rust infection types (ITs) produced on test wheat lines and cultivars from nine yellow rust races were compared with ITs produced on standard differential lines that differed for specific yellow rust resistance genes. The experiment was conducted at seedling stage under greenhouse conditions in Goettingen, Germany
during 2001. The result indicated that most of the advanced bread wheat lines possess different yellow rust resistance genes when compared to the commercial cultivars. Seedling genes Yr1, Yr2, Yr3V, Yr4, Yr6 and Yr17 with or without Yr9 were postulated to be present in 11 advanced lines. However, only Yr7 and Yr9 were postulated to be present in five of the commercial bread wheat cultivars. The newly identified resistance sources could be of great importance for enhancing the genetic base of resistance of bread wheat to yellow rust in Ethiopia.

Keywords: Race; Resistance Gene; Virulence; Yellow or Stripe Rust

East African Journal of Sciences Vol. 2 (1) 2008: pp. 29-34