Nodulation and nitrogenase activity of chickpea cultivar INRA 199 inoculated with different strains of Rhizobium ciceri

The nitrogen-fixing capacity of 12 collection strains of R. ciceri in symbiosis with chickpea INRA 199 was estimated in the greenhouse by comparison with plant growth in the absence of mineral nitrogen. The strains were separated into 4 groups of significantly different effectiveness. The magnitude of the energy loss in nodule hydrogen production by these strains was estimated to vary between 0.19 and 0.77 in a controlled environment. No hydrogenase activity was detected in any of the associations. In the field, hydrogen production represented 40 % of the energy supply to nitrogenase activity during the growth cycle. A survey revealed considerable variation in nodulation, and in effectiveness of symbiosis, with the Rhi!obiutii strains naturally present in soils where chickpea may be grown in future. In some fields there was no spontaneous nodulation. In the majority of fields, the mean dry weight of nodules per plant was around 200 mg at flowering ;maximum field nodulation was 700 mg DW nodule plant ’.