Leaf Surface Wax as a Possible Resistance Factor of Barley to Cereal Aphids

Abstract
The role of leaf surface wax in the resistance of barley to cereal aphids, especially the dominant species Rhopalosiphum padi (L.), was studied. Aphid infestations were semilogarithmically proportional to the amount of surface wax. Furthermore, the results from hybridization experiments between a susceptible line, f9-gl3-Hs-k, and a resistant line, Spontaneum II, showed that the level of resistance to the aphids correlated positively with surface wax rather than with leaf colour. Therefore, it is likely that at least part of the resistance to cereal aphids shown in some barley lines is attributable to surface wax.