Abstract

MAYZ, Juliana; LAREZ, América  and  ALCORCES, Nilda. Effectiveness of savannah native rhizobial strains in Vigna unguiculata (L.) Walp. cv. C4A-3. Rev. colomb. biotecnol [online]. 2010, vol.12, n.2, pp.194-202. ISSN 0123-3475.

It is estimated that world-wide population will increase and demand higher amount of food and use of nitrogen fertilizer. In Venezuela, cowpea is highly consumed and is cultivated in eastern savannahs, whose soil characteristics may negatively affect rhizobial population. These expositions reinforce the importance of the evaluation of the native rhizobial flora and emphasize the necessity to increase the exploitation of the Biological Nitrogen Fixation. In this context, 6 rhizobial strains isolated from cowpea cv. Tejero Criollo non-inoculated and previously catalogued as effectives (JV91, JV94 y JV101) and ineffectives (JV99, JV103, y JV104) in cultivar TC9-6 were evaluated in the cultivar C4A-3. The experiment was carried out in greenhouse by 45 days, where in addition, two non-inoculated control treatments were included. Suspension of individually cultivated strains was used for inoculation. Accordingly with nodulation typology (nodule number, total dry weight and per nodule and colour), growth parameter values (shoot dry weight, height and leaves number) and nitrogen concentration and total nitrogen estimates, the strains JV91, JV99 and JV101 were the most effective in nitrogen fixation. Total nitrogen and concentration correlated significantly with dry weight and height of shoots and leaves number. The results show the existence of effective strains in savannah soils for this cultivar, and emphasize the importance of evaluating the indigenous strains, before proceeding to inoculate with foreign strains.

Keywords : Rhizobium; cowpea; nitrogen fixation; Venezuela.

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