Influence of intergeneric grafts between host and non‐host legumes on formation of vesicular–arbuscular mycorrhiza

summary Stem grafts were carried out between different varieties of vesicular‐arbuscular (VA) mycorrhizal host (pea, soybean) and non‐host (lupin) legumes. Only grafts on host rootstock were successful. Self‐grafts of three pea varieties (Amino, Solara, Frisson), and interspecific grafts between soybean (var. Amsoy 71) and pea (var. Frisson), did not generally affect development of, or arbuscule formation by, Glomus intraradices Schenck & Smith or G. mosseae Nicol. & Gerd. within the rootstock. In contrast, lupin (var. Alban and Lucky) scions greatly reduced colonization of the root cortex and completely inhibited arbuscule formation by both fungi in grafted pea rootstock. The possible role of mobile shoot factors in non‐host resistance to VA mycorrhizal fungi in lupins is discussed.