THE EFFECT OF VESICULAR-ARBUSCULAR MYCORRHIZAL INOCULATION ON THE GROWTH AND ROOT COLONIZATION OF 10 STRAWBERRY CULTIVARS

Ten strawberry cultivars, four early maturing, three late maturing and three ''special'' cultivars, were inoculated with six strains of vesicular-arbuscular mycorrhizal (VAM) fungi in a pot experiment. Growth effects and colonization of the VAM fungi were studied. Three strains, Glomus macrocarpum V3, G. mosseae Rothamsted and G. sp. V4, were highly efficient, causing significant growth increases in most cultivars. 'Jonsok' showed the highest mycorrhizal dependency index, 648, and 'Ostara' the lowest, 269, for the mean response of all six fungi. The fungal strains which increased shoot growth the most also increased the runner plant formation the most. Early cultivars showed higher colonization percentages than late maturing cultivars. Sporulation of the introduced VAM fungi was on average more abundant in early and special cultivars than in late cultivars. Root colonization and strawberry shoot dry weight correlated significantly in most cultivars, but the correlation between colonization and runner formation was generally poor.