Relationship between Resistance to Cereal Aphids and Gramine Concentration in Beer Barley

To beer barley resistance to cereal aphids, the relationship between the aphid density and gramine concentration was examined in various barley lines including beer barley cultivars. All beer barley cultivars tested were resistant or moderately resistant to the aphids, especially Asahi 5 and Haruna Nijo were similar to a wild line, H603 (W603), for checking resistant. However, these beer barleys contained much less gramine than the wild barley line, suggesting that another resistant factor(s) affects cereal aphid density.