The inheritance of mechanisms of partial resistance to Erysiphe graminis in spring barley

Publisher Website
Google Scholar
Abstract
The response of epidermal cells to attempted penetration by Erysiphe graminis was examined in the fifth leaf of 13 barley lines selected for partial resistance. In leaf segments fixed and stained 72 h after inoculation cell reactions were classified as susceptible or as exhibiting non‐hypersensitive or hypersensitive resistance. The proportion of cells with each type of reaction varied in a continuous manner among the lines and there were significant differences between lines in the levels of non‐hypersensitive and hypersensitive resistance. Crosses were made between lines exhibiting high and low levels of each resistance mechanism. Fifty challenged epidermal cells per duplicate leaf segment were examined on 45‐50 F2 plants derived from two such crosses. The frequency distribution of each of the three types of cell reaction in the fifth leaf was found to be continuous and, in general, normally distributed and in no case was there a significant difference between parent and progeny mean values, suggesting that the two resistance mechanisms were under the control of several genes showing predominantly additive gene action.