Effect of genotype of Trifolium repens on mycorrhizal symbiosis with Glomus mosseae

Forty-three near-isogenic lines (NILs) of white clover (Trifolium repens), derived from four parental self-compatible genotypes containing the rare se lf-fertility allele, were inoculated with the arbuscular mycorrhizal fungus Glomus mossac. Plant growth response (shoot and root weight and root lengt h), shoot P uptake and mycorrhizal root infection rates were recorded 12 we eks after inoculation. There was generally a high degree of variation betwe en individual lines in all recorded parameters. The most sensitive indicato r of plant response to mycorrhizal infection was root length with almost ha lf of all lines showing significant responses (in most cases a decrease in root length). Shoot weight was significantly different between mycorrhizal and nonmycorrhizal plants in nine lines. Parental genotype significantly af fected both plant response to mycorrhiza as well as mycorrhizal infection r ates. The results suggest that the NILs will prove useful for further studi es to elucidate the molecular genetic control of the symbiosis and inform p lant breeding strategies of this agronomically important species.