Symbiotic nitrogen fixation by two lentil cultivars in relation to rhizobium strain, competition and irrigation rates

ABSTRACT

Two Rhizobium Leguminosarum strains TAL 638 and Nitragin 92 A3 were studied in their relation to fix atmospheric nitrogen with two lentil cultivars. The experiment was conducted in a Delta Nile clay loam soil using two rates of irrigation. regardless the irrigation. regimes, the inoculation of lentil with these strains either singly or in combination induced significant increase in plant dry weight. nitrogen fixation grad seed yield. Giza 370 cultivar in symbioses with any of the strains was superior in nitrogen accumulation and seed yield than Giza 9 cultivar. However. the strain X varicty interaction was not significant. The nitrogen fixation and thee yield of both lentil cultivars were significantly affected by water regime. The frequent irrigation resulted in higher plant dry weight. N accumulation and seed yield with both cultivar The inoculum strain outcompeted the resident rhizobia. Between 72-92% of nodules were occupied by the strains used as single inoculum. In double, strain inocula, R. leguminosarum strains, TAL 638 and Nit. 92 A3 were equailly, competitive on both cultivars under the two irrigation regimes. The incidence of double strain occupancy within the nodules collected from the double strain inocula ranged between 0 to 38%