Subunits of tetrameric α-amylase inhibitors of Hordeum chilense are encoded by genes located in chromosomes 4H(ch) and 7H (ch.).

Three proteins (components 1, 2, and 4) of the non-prolamin, 70% ethanol soluble fraction from the endosperm of Hordeum chilense have been identified as putative subunits of the tetrameric inhibitors active against insect α-amylases. In experiments carried out with the synthetic alloploid Tritordeum (H. chilense x Triticum turgidum conv. durum), previously described proteins from T. turgidum, designated CM2, CM3 and CM 16, have been also identified as subunits of α-amylase inhibitors. Genes for components 1 and 4 of H. chilense have been located in chromosomes 4H(ch) and 7H(ch), based on the analysis of H. chilense-T.turgidum addition lines. Subunits of the inhibitors from wheat and from cultivated barley had been previously assigned to chromosomes of the same homoeology groups.