Table of Contents
International Scholarly Research Notices
Volume 2014 (2014), Article ID 258497, 8 pages
http://dx.doi.org/10.1155/2014/258497
Research Article

Symbiotic Efficiency of Native Rhizobia Nodulating Common Bean (Phaseolus vulgaris L.) in Soils of Western Kenya

1Department of Applied Plant Sciences, Maseno University, Maseno, Kenya
2Department of Pure and Applied Sciences, Technical University of Mombasa, P.O. Box 90420, Kenya
3Department of Soil Science, Maseno University, Maseno, Kenya
4Department of Plant Sciences, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya
5Department of Microbiology, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya
6Department of Biochemistry and Biotechnology, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya
7Department of Soil Science, Makerere University, P.O. Box 7062, Kampala, Uganda
8Faculty of Applied Sciences, Kigali Institute of Science and Technology, P.O. Box 3900, Kigali, Rwanda
9Department of Biological Sciences, Masinde Muliro University of Science and Technology, P.O. Box 190-50100, Kenya

Received 20 August 2014; Accepted 14 October 2014; Published 11 November 2014

Academic Editor: Arthur P. Schwab

Copyright © 2014 Fanuel Kawaka et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This study was conducted to determine the abundance and symbiotic efficiency of native rhizobia nodulating common bean in Kisumu and Kakamega, Kenya. Soil sampling was carried out in three farms that had been used for growing common bean for at least two seasons and one fallow land with no known history of growing common bean or inoculation. Abundance of soil rhizobia and symbiotic efficiency (SE) were determined in a greenhouse experiment. Native rhizobia populations ranged from to cells per gram of soil. Pure bacterial cultures isolated from fresh and healthy root nodules exhibited typical characteristics of Rhizobium sp. on yeast extract mannitol agar media supplemented with Congo red. Bean inoculation with the isolates significantly increased the shoot dry weight and nitrogen (N) concentration and content. The SE of all the native rhizobia were higher when compared to a reference strain, CIAT 899 (67%), and ranged from 74% to 170%. Four isolates had SE above a second reference strain, Strain 446 (110%). Our results demonstrate the presence of native rhizobia that are potentially superior to the commercial inoculants. These can be exploited to enhance bean inoculation programmes in the region.