Virulence factors of Puccinia triticina on wheat and effectiveness of Lr genes for leaf rust resistance in Ardabil

Abstract

Rust diseases of wheat (Triticum aestivum L.) are major constraints to production in most wheat-growing regions of the world. Leaf rust, caused by Puccinia triticina Erikss, is one of the most important diseases of wheat in Iran, second to yellow rust. Control of this disease has often been achieved through the use of race-specific resistance genes. However, these types of genes have been quickly overcome by new virulent pathotypes (races) of pathogen. Hence, the knowledge of effective resistance genes in the region will enable breeders to target those useful genes in their breeding programmes. From 2007 to 2012, in order to determine the effective resistance genes in Ardabil, north-west of Iran, virulence patterns of wheat leaf rust were studied under the field conditions by planting of wheat genotypes and near-isogenic lines. The results showed that leaf rust resistance genes Lr17, Lr18, Lr19, Lr22a, Lr23+, Lr25, Lr28, Lr35 and Lr36 and the combination of genes Lr13, Lr27, Lr31 and Lr34 with together/other resistance genes in wheat genotypes Noroeste, Opata 85, Anahuac 75, Genara 81, Super Seri #2, Babax #1, Babax #2, Super Kauz, Tonichi 81, and Parula were effective during study periods. The genotypes having resistance genes Lr22b, Lr1, Lr2b, Lr2c, Lr3, Lr3ka, Lr3bg, Lr10, Lr11, Lr13, Lr14b, Lr16, Lr20, Lr30, Lr33, Lr34, Lrb, Lr37 showed susceptible (S) reaction at least twice during study periods and were found ineffective. The genes found effective against leaf rust under natural conditions may be deployed singly or in combination with durable resistance genes to develop high-yielding resistant wheat cultivars in wheat-growing areas in where leaf rust races have the same virulence profile to the prevalent race/s of Ardabil.

Keywords:

• wheat
• leaf rust
• virulence
• effective Lr genes

Acknowledgements

Financial support and the provision of facilities from Seed and Plant Improvement Institute (SPII) and Agricultural and Natural Resources Research Center of Ardabil for this research is gratefully acknowledged.