Selection of Rhizobium strains for inoculation of Lithuanian Pisum sativum breeding lines

Pea (Pisum sativum) is one of the most popular legume crops used in agriculture. Because of the high demand and relatively reasonable price, Lithuania has increased the cultivation of this crop and invested in the research of new effective breeding lines in the last years. Rhizobial inoculants contribute to increasing yield in legumes through N2 fixation. Therefore, the objective of this work was to identify rhizobial strains able to increase the activity of two pea breeding lines (‘DS 3637–2’ and ‘DS 3795–3’) known for high productivity, resistance to biotic and abiotic stresses, and competitiveness in respect to weeds. Six rhizobial strains isolated from pea plants were identified as members of the Rhizobium leguminosarum group and phenotypically characterized in depth by Phenotype Microarray (PM). Phenotypic differences observed were linked to their phylogeny. Then, strains were tested for their ability to stimulate the growth of the breeding lines ‘DS 3637–2’ and ‘DS 3795–3’. Reference strain Rhizobium anhuiense Z1 and Rhizobium leguminosarum sv. viciae 14ZE showed the best symbiotic performances with breeding lines ‘DS 3637–2’ and ‘DS 3795–3’, respectively. Based on the obtained results, R. leguminosarum sv. viciae strain 14ZE appears to be a new effective inoculant of peas.