Seedling resistance of wheat to the powdery mildew fungus, Erysiphe graminis f. sp. tritici. I. Resistance of first leaves

The expression of components of seedling resistance to Erysiphe graminis f.sp. tritici in Triticum timopheevii and a hexaploid derivative

“…However, the new method followed in calculating sequentially the efficiency of each barrier during the histological studies, and in estimating sporulation capacity, allows us to base our conclusions concerning the experimental host genotypes on truly comparable data. The conclusion of Ghemawat (1979) that an increase in the number of hairs ean reduce the number of conidia deposited on the leaf surface could not be substantiated, but there could be a correlation between hair density and the overall level of resistance which substantiates Homma's observation (1937) that the susceptible variety had fewer hairs Although the hairs and their basal cells were immune from infection at the cuticle, this eannot be considered as a significant factor affecting the overall level of resistance because they occupied a relatively small proportion of the total leaf surface area.…”

“…Potential barriers to the infection of wheat and barley by E. graminis have been described by many authors (e,g, Hyde & Colhoun. 1975;Toyoda et ai, 1978;Ghemawat. 1979;Wright & Heale.…”