Study on some Components of Resistance and Development of Blumeria graminis f.sp. tritici, in Six Wheat Lines

Development of Blumeria graminis f.sp. tritici (Bgt) on leaf surface of six advanced wheat lines and some resistance components were studied using a pathotype of Bgt having numerous virulence factors. Wheat lines were two resistant, M-81-13 and N-78-8, two moderately resistant, C-80-4 and N-80-6 and two susceptible, N-79-7 and N-80-19. Seeds of lines were sown in greenhouse and seedlings were inoculated with conidia. Plants were incubated and maintained in constant conditions (95-100% R.H. and 12 /12 hour light / dark period at 18-20ºC) in the greenhouse. Latent period and colony size were measured regularly after inoculation, and different developmental stages of the fungus were studied under light microscope, The results showed that percentages of conidia germination, primary and secondary germ-tube, conidiophore and conidia formation, colony size and fungal development were lower in resistant line than those in moderately resistant and susceptible lines. Slow development of the pathogen on resistant lines due to these mechanisms of resistance, caused longer latent period in those lines.