Stripe rust resistance genes in a set of Ethiopian bread wheat cultivars and breeding lines

Stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is one the most important diseases of wheat in Ethiopia and worldwide. To identify resistance genes, 90 bread wheat lines and 10 cultivars were tested at the seedling stage against one Pst race from Ethiopia and six races from China as well as evaluated for the stripe rust response in an inoculated field nursery at Yangling, Shaanxi province and in a naturally infected field in Jiangyou, Sichuan, China. Resistance genes were postulated using molecular assays for Yr9, Yr17, Yr18, Yr26, Yr29, Yr36, Yr44 and Yr62. Of the 100 entries tested, 16 had all stage resistance to all races. Molecular markers were positive for Yr9 in five genotypes, Yr17 in 21 genotypes, Yr18 in 27 genotypes, Yr26 in ten genotypes, Yr29 in 22 genotypes, Yr36 in 12 genotypes, Yr44 in 30 genotypes, and Yr62 in 51 genotypes. No line had Yr5, Yr8, Yr10 or Yr15. Complete or all stage resistance was observed in genotypes carrying gene combinations Yr9 + Yr18 + Yr44 + Yr62, Yr29 + Yr62 + Yr26 and Yr9 + Yr17 + Yr26 + Yr44 + Yr62. The results are helpful for developing wheat cultivars with effective and more durable resistance to stripe rust both in China and Ethiopia.