Nitrogen Fixing Bacteria for Nodulation in Legumes,Legume Rhizobium Symbiotic Nitrogen Fixation

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	Nitrogen Fixing Bacteria for Nodulation in Legumes - It is well known that Rhizobium forms symbiotic association in the roots of leguminous crops, leading to the formation of nodules, which help in improving the fertility of soil through fixation of nitrogen from the atmosphere. Extensive studies on the genes of host as well as the symbiont, responsible for nitrogen fixation have been undertaken during the past few decades giving valuable information for future genetic engineering exercises. This may eventually lead to better legume - Rhizobium symbiotic nitrogen fixation. The use of legume - Rhizobium system for restoration of degraded lands may involve the following steps:
(i) produce inoculum of selected rhizobial strains on a commercial scale; (ii) evolve effective and efficient carriers of inoculum for field inoculation and (iii) evolve suitable technique for rapid seedling establishment and nodulation. Different Rhizobium strains may be suitable for different soils. For saline soils, R8 and for acidic soils R36 and R73 were found useful. Trees associated with rhizobia can also be used for reforestation on degraded lands. Micropropagation has been used with several leguminous tree species to be used for plantations on degraded lands. These tree species include the following: Acacia nilotica, Albizia lebbeck, Dalbergia latifolia, D. sissoo, Leucoena, leucocephala, Prosopis cineraria, Sesbania grandiflora and S. sesban.