Raúl C. López Sánchez, Ernesto Gómez Padilla, Bettina Eichler-Loebermann, Mercedes Fernández-Pascual, Beatriz Ruiz-Díez, Roeland Samson, Patrick van Damme:
Response of Clitoria ternatea and Vigna unguiculata to Inoculation with Rhizobium and Bradyrhizobium Strains in Salt-affected Soils in the Cauto Valley, Cuba

RAÚL C. LÓPEZ SÁNCHEZ¹, ERNESTO GÓMEZ PADILLA¹, BETTINA EICHLER-LOEBERMANN², MERCEDES FERNÁNDEZ-PASCUAL³, BEATRIZ RUIZ-DÍEZ³, ROELAND SAMSON⁴, PATRICK VAN DAMME^5
1University of Granma, Faculty of Agricultural Sciences, Cuba
²University of Rostock, Faculty of Agricultural and Environmental Sciences, Germany
³Council of Higher Scientific Investigation, Spain
⁴University of Antwerp, Department of Bioscience Engineering, Belgium
⁵University of Ghent, Department of Plant Production - Laboratory for Tropical Agronomy, Belgium

In Cuba, about 1.000.000ha of crop soils are affected by salinity. This also causes considerable losses in pasture yields and animal production. One of the alternatives to improve the fertility of these soils is the use of salt-tolerant legume species. Legumes may help to (1) improve the quality of salt"=affected soils due to their capacity to fix atmospheric nitrogen (N) in symbiosis with Rhizobium; (2) increase soil organic matter; (3) serve as a protection against erosion; and (4) improve soil structure. The response of two tropical legume species, i.e. Clitoria ternatea and Vigna unguiculata, inoculated with native and commercial Rhizobium and Bradyrhizobium strains was studied under soil salt stress conditions. The study was carried out under field conditions. The effect of three Rhizobium strains (Jd19, 1031 and 1032) in C. ternatea and two Bradyrhizobium strains (VIBA"=1 and VIBA"=2) in V. unguiculata were compared to a control (without fertilisation and inoculation). using yield and nitrogen fixation parameters. In C. ternatea, Jd 19 had the highest effects on dry matter yield, ureide content and N accumulation. The inoculation effectiveness index was very close to the nitrogen response index for this species. In V. unguiculata, results show Bradyrhizobium strains to have a beneficial effect on different variables. Especially VIBA"=1, improved nodule number, their dry mass and specific nitrogen fixation, as well as eventual crop yield. The highest effectiveness index value was also obtained when using VIBA"=1.VIBA"=2 showed better results than control. Positive linear and highly significant correlations were found between nodulation and nitrogen fixation, and total nitrogen content in plant tissue and plant yield.

Keywords: Legumes, nitrogen fixation, salt stress

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Contact Address: Raúl C. López Sánchez, University of Granma, Faculty of Agricultural SciencesMarti 4141 altos entre C.Montero  y J. Medina, 85100 Bayamo, Cuba, e-mail: rlopezsudg.co.cu