E4D Fellow: Samuel Mathu Ndungu

Project description

Cowpea is the most important legume in the dry lands of Eastern and Coastal Kenya mainly cultivated by smallholder farmers. Cowpea yields are low partly due to poor soil fertility. This project aims to improve cowpea yield for farmers in two agro-ecologies (Kilifi, Coastal lowland and Mbeere, Lower midland) in Kenya through inoculation with elite Bradyrhizobia. Firstly, by isolation and characterization of Bradyrhizobia nodulating cowpea in both agro-ecologies from diverse sites. Matrix Assisted Laser Desorption/ionization Time of Flight (MALDI-TOF) mass spectrometry (MS) is rapid and accurate, hence suitable for strain characterization. After characterization, genetically distinct strains will be screened for symbiotic efficiency and competitiveness in growth chamber trials using axenic conditions by inoculating to cowpea individual strains and a mixture of them. Strain competitiveness will be assessed with MALDI-TOF by determining nodule occupancy in treatments with strain mixtures. Four best performing strains from the screening will be validated on farmers’ fields and MALDI-TOF used to assess strain competitiveness in presence of native strains. Finally, functional gene analysis will be done on selected symbiotic genes to investigate their role in efficient Biological nitrogen fixation (BNF) and strain competitiveness. Via application of novel assays to study the cowpea-Bradyrhizobia symbiosis, yields and soil fertility status can be improved to enhance food security.