Evaluation of CIMMYT synthetic hexaploid wheats for resistance to septoria tritici blotch

Abstract

Of 128 genotypes, 60 synthetic hexaploid wheat genotypes showed no resistance response, whereas the remaining genotypes showed specific resistance to one or more isolates. Interestingly, nine genotypes were resistant to all isolates tested. Isolate RM46 collected from Khuzestan Province was virulent on 87% of SHWs, suggesting that it has the lowest number of avirulence genes. Isolate RM155 collected from Golestan Province displayed the highest number of incompatible interactions (n=42), indicating that it possesses the highest number of avirulence genes. RM151 was the most aggressive isolate with the highest mean disease severity (69%), whereas RM41 was the least aggressive isolate with the lowest mean disease severity (37%). The present study was the first conducted to evaluate CIMMYT SHWs for resistance to Iranian Z. tritici isolates. Our results showed that some SHWs possess a broad spectrum of resistance gene(s) or a combination of a set of effective genes against various STB isolates