Isolation and Assessment of the Symbiotic Efficiency of Faba bean (Vicia faba L.) Nodulating Rhizobial Isolates from Eastern Hararghe Highlands of Ethiopia

Mulugeta Mekonnen,Ameha Kebede

doi:10.12944/carj.9.2.04

Abstract

This particular work was devoted to isolate and assess the symbiotic efficiency of faba bean (Vicia faba L.)-nodulating rhizobia isolate at few faba bean growing areas of the eastern Hararghe highlands of Ethiopia. Overall 50 rhizobia isolates were obtained from soil samples of three Woredas (districts) of the eastern Hararghe highlands using the host trap method. Out of these 50 isolates, 40 were presumptively identified as rhizobia. Among these 40 rhizobia isolates, only 31 were successful to nodulate faba bean, and authenticated as true faba bean nodulating rhizobia. Concerning the symbiotic efficiency, about 52%, 35%, and 13% of the rhizobial isolates were found to be highly effective, effective, and lowly-effective, respectively. The correlation data on the sand experiment displayed that nodule dry weight was associated positively and significantly (r = 0.494, p<0.05) with shoot dry weight while shoot dry weight was associated positively and significantly (r=0.41, p<0.05) with plant total nitrogen. Positive correlations were also observed concerning shoot dry weight and dry weight of nodules (r = 0.7, p<0.05) on unsterilized soil. Among the observed rhizobium isolates, EHHFR (4A, 6A) showed the highest symbiotic efficiency above 110%, tolerated NaCl concentration ranging from 2% to 6% and 2% to 8%, respectively, and a pH range of 4.5 to 8 and 5 to 8, respectively. Thus, based on their symbiotic efficiency at the greenhouse level and relative tolerance to extreme conditions these faba bean nodulating rhizobia isolates were recommended to be used as nominees for the future development of faba bean rhizobial inoculants after being tested on field conditions.

Highlights

The conversation of N2 gas into ammonia by a biological nitrogen fixation has significant meaning in improving soil productiveness, health, and yield of crops.The nitrogen-fixing system in general offers an economically attractive and ecologically all-encompassing means of decreasing none environmentally friendly inputs and enhancing internal resources like nitrogen and organic matter content of the soil.inoculating faba bean can curve low productivity of the crop where there are signsofyield declining and nitrogen deficiency symptoms (FAOSTAT, 2010)
Isolation and Presumptive Test for Identification of Rhizobia A total of 50 isolates were obtained from soil samples of three Woredas of the eastern Hararghe highlands of Ethiopia using the host trap method
Aynabeba et al (2001) and Argaw (2012) indicated that except few almost all of the presumptively identified faba bean rhizobia were authenticated as root nodule bacteria

Summary

Introduction

The conversation of N2 gas into ammonia by a biological nitrogen fixation has significant meaning in improving soil productiveness, health, and yield of crops.The nitrogen-fixing system in general offers an economically attractive and ecologically all-encompassing means of decreasing none environmentally friendly inputs and enhancing internal resources like nitrogen and organic matter content of the soil.inoculating faba bean can curve low productivity of the crop where there are signsofyield declining and nitrogen deficiency symptoms (FAOSTAT, 2010). The conversation of N2 gas into ammonia by a biological nitrogen fixation has significant meaning in improving soil productiveness, health, and yield of crops. Only a few studies have been done on finding symbiotically efficient faba bean nodulating rhizobial isolates at the Eastern Hararghe highlands of Ethiopia. This study was carried outaiming to find symbiotically efficiency of faba bean nodulating rhizobial isolates around Eastern Hararghe highlands of Ethiopia. It improves soil health by supporting the progression of other beneficial soil microorganisms such as fungi, actinomycetes, and bacteria if the roots of the legumes are left in the ground. Legumes like faba bean play a major part in enhancing the income of poor farmers by serving as food, feed, and at the same time, it plays a major part in enhancing soil fertility

Methods

Results

Conclusion