Investigation of Virulence Factors of Stem Rust Puccinia graminis f. sp. tritici in Ardabil Province in three consecutive years (2017-2019)

Stem or black rust caused by Puccinia graminis f. sp. tritici (Pgt) is one of the most common and harmful wheat diseases in Iran and worldwide. Under favorable conditions and the formation of the disease pyramid, the pathogen can destroy the wheat crops in a short time. Pgt has high genetic variability in the population structure due to the completion of the sexual cycle, which causes the creation of new races (race diversity) with a completely different pathogenicity pattern. TTKSK (Ug99) is one of the most critical race of Pgt that has appeared in recent decades and has caused much damage to wheat crops worldwide. This race had identified and reported in the country. However, the safest and at the same time most cost-effective way to manage and control this disease is to use genetic resistance. Accurate knowledge of the genetic structure of the pathogen population (existing races) in each region and knowledge of the virulence factors (genes) of stem rust races is the first step and similar to the roadmap to achieve effective and stable genetic resistance. One way to study the trend of changing pathogenicity patterns of races in each region is to observe virulence factors on stem rust differential genotypes in a trap nursery. For this purpose, virulence factors of Pgt races and the effectiveness of resistance genes in international differential genotypes investigated for three consecutive years (2017-2020) in the Ardabil province.