Symbiotic Efficiency of Native Rhizobia Nodulating Common Bean (Phaseolus vulgaris L.) in soils of Western Kenya
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Date
2014
Authors
Ombori, O.
Maingi, J.M.
Kawaka, Fanuel
Dida, Mathews M.
Osoro, N.
Opala, Peter A.
Muthini, Morris
Muoma, John
Amoding, Alice
Mukaminega, Dative
Journal Title
Journal ISSN
Volume Title
Publisher
International Scholarly Research Notices Volume 2014 (2014), Article ID 258497, 8 pages http://dx.doi.org/10.1155/2014/258497
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 of 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 3.2 × 101
– 3.5 × 104
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 (p < 0.05) increased the shoot dry weight, 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