Mycorrhization of winter wheat cultivars in organic farming

The root length density, arbuscular mycorrhizal (AM) colonisation and the total AM root length density of 12 winter wheat cultivars have been studied at seven sites in eastern Austria under organic farming. Root length density did not differ between the cultivars whereas AM colonisation and total AM root density did. Site effects were more pronounced than cultivar effects. All three traits generally were on a higher level in calcaric Phaeozems than in Cambisols. The AM colonisation and total AM root density decreased with increasing plant height and were positively correlated with crop yield. On calcaric Phaeozems, root length density in the subsoil was obviously more important for drought tolerance than AM colonisation in the topsoil.