Symbiotic interactions between Rhizobium leguminosarum strains and elite cultivars of Pisum sativum L.

Pea (Pisum sativum L.) is an important world grain legume and vegetable in the south of Europe where it is grown in small farms and gardens during the cool season. Most of the pea production of this area occurs in high nitrogen (N) soils. Inoculation is required to increase yields through N fixation and reduce the external inputs. Three pea elite cultivars representing human food market classes (green, sugar and dry peas) were studied in order to characterize the cultivars' variability in symbiotic characters using two Rhizobium leguminosarum biovar viceae commercial strains and the indigenous soil strain, and three N-fertilization rates. Significant differences were observed among pea elite cultivars for the weight and length of plant parts, and the traits associated with N fixation. Pea cultivars showed a significant cultivar-strain interaction for shoot fresh weight and significant differences among strains were found for nodule fresh weight. Green and sugar pea cultivars had good N fixation with a particular commercial strain, while the dry pea cultivar did not show an effective symbiotic combination. The differences between the pea cultivars could be exploited in breeding programs for enhanced nodulation and N fixation in each pea market class.