Assessment of Quality Control of Inoculants Used on Bean and Soybean in Eastern and Central Africa

Mwanga, Isaac Balume Kayani (2013) Assessment of Quality Control of Inoculants Used on Bean and Soybean in Eastern and Central Africa. Masters thesis, University of Nairobi.

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Abstract

There is increased adoption of rhizobia based legume inoculation by small-scale farmers in East and Central Africa. This technology supports the exploitation of biological nitrogen fixation on the assumption that quality inoculants in the market meet minimum standards. In East Africa BIOFIX® developed at the MIRCEN laboratory has been used for over 30 years and when applied to soybean or common been seeds the product is able to furnish at least 109 rhizobia g-1. This study examined the effect of carrier materials and storage conditions for inoculants. The inoculants were prepared using two industry standard rhizobia, Bradyrhizobium japonicum USDA 110 for soybean (Glycine max) and Rhizobium tropici CIAT 899 for common bean (Phaseolus vulgaris). The storage experiments were conducted for 165 days and the number of viable rhizobia was determined using the drop plate method on Congo Red Yeast Extract Mannitol Agar. The study established that viable populations of rhizobia differed significantly between carriers (P<0.001) Rhizobia strain R. tropici CIAT 899 prepared with filter mud as carrier achieved a shelf life of 135 days while B. japonicum USDA110 maintained over 109 cells g-1 for 105 days. The results fall below the stated six month expiry period of BIOFIX®. Studies on potential alternative carriers such as vermiculite were carried out but it turned out that these materials were inferior to filter mud. While BIOFIX® meets reasonable standards in terms of rhizobia counts; it must not be used beyond the specified expiry period. The study also found out that even under refrigeration, the expiry period does not change significantly. Contaminants found in carriers were also evaluated in BIOFIX® legume inoculants. Contaminants in BIOFIX® inoculants determined after 105 days of incubation were found to be mainly fungi. The number of contaminants was in the magnitude of 106 cells g-1.

Item Type:	Thesis (Masters)
Subjects:	S Agriculture > S Agriculture (General)
Divisions:	Africana
Depositing User:	NLANDU Ephraim DIKUIZA
Date Deposited:	21 Jul 2016 06:47
Last Modified:	21 Jul 2016 06:53
URI:	http://thesisbank.jhia.ac.ke/id/eprint/751

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