Nodulation of Lupinus albus and Vicia faba by Rhizobium spp. as influenced by Agrobacterium rhizogenes

Nodule number per plant of Lupinus albus cv. Uniwhite and Vicia faba cv. Minor was increased 66.7% and 81.4%, respectively by co-inoculation of young plantlets with specific strains of Rhizobium spp. and Agrobacterium rhizogenes (a root proliferating organism). In all cases, however, the increase in nodule number was accompanied by a reduction in their dry weight. The number of nodules per gram root dry weight increased significantly for Lupinus albus but was unchanged for Vicia faba. This indicates an increase in root weight in Vicia faba, resulting in no change in the nodule number per gram dry matter of roots.