Screening of dryland bread wheat genotypes against yellow rust through greenhouse and multi-environmental trials

Yellow rust of wheat caused by Puccinia striiformis f. sp. tritici is one of the most important wheat diseases that threaten its production. Host resistance is the most economical and healthiest method of yellow rust management. In this study, slow rusting resistance parameters including infection coefficient, disease severity as well as reaction type were recorded for 48 rain-fed wheat genotypes along with sensitive control in 6 rain-fed environments. The field experiment was done for two consecutive years in three distinct geographical regions including Ardebil, Zarghan, and Mashhad. The additional screening test was established in greenhouse conditions. Results showed genetic variability among studied germplasms in resistance against yellow rust. In this research, G1, G04, G05, G06, G20, G21, G32, G33, G39, and G45 out of the studied genotypes had resistant and stable reactions across years and locations. Ward clustering algorithm produced three heterotic groups which can be utilized in yellow rust breeding programs through parental selection for the construction of a yellow rust mapping population. Differential genotypes testing resulted in “6E142A +, Yr27”, “38E158A +, YR27” and “134E150A +, YR27” isolates which belonged to Ardebil, Mashhad as well as Zarghan regions respectively. The resistance reaction in the seedling stage varied from that found in the field state which indicated the existence of adult plant resistance genes in their genome.