Physiological races of Puccinia graminis f. sp. tritici in Iran and evaluation of seedling resistance to stem rust in Iranian wheat cultivars

Abstract

Seedling assessment of 13 stem rust samples collected from southwest of Iran revealed that three collec- tions were virulent for Sr31 and Sr38. Physiological races of RTRTC, HRCTC, RRTTF, TTPTC, TTTQF, JTHTC and TTKSK were identified for nine collections tested against the north American differential lines. The virulence pattern of TTKSK previously identified in east Africa was identical to that of TTKSK in the present study, providing evidence for the migration of this race from East Africa to Iran. Low/ high infection type for the genes Sr22, Sr26, Sr27, Sr29, Sr32, Sr33, Sr35, SrNin/ Sr7a, Sr8b, Sr9f, Sr12, Sr15, Sr16, Sr17, Sr18, Sr20, Sr23, Sr34, SrPL, SrTt3+10, SrWld-1, and Sr42 was shown by nine collections. In evaluations of seedling resistance, high infection types of 3 to 4 were shown by all the 29 Iranian wheat cultivars tested with TTKSK. Presence of TTKSK, susceptibility of wheat cultivars and conducive conditions pose serious threats of stem rust to wheat production in Iran.