Response of groundnut varieties and commercial rhizobia bio-fertilizers in two locations of Uganda

Abstract

Rhizobia bio-fertilizer inoculation is an environmentally-friendly and cheaper option for smallholder farmers to improve legume productivity and soil fertility. However, there may be variations in legume variety response to inoculation. Therefore, on-station field experiments were conducted in two locations of Uganda to determine response of groundnut varieties to bio-fertilizers. The experiments were arranged in split plots under randomized complete block design with four varieties of groundnut as main treatments and inoculation and no inoculation as sub-treatments. The results showed that inoculation of groundnut with the Mak-Bio-Fixer and Biosoil Nitro+ significantly (P<0.001) increased the number of effective nodules and shoot N at 45 days after plating in all the tested varieties with the exception of the Red Beauty variety. The grain yield response ranged from 0 to 37% with the Serenut 5R giving the highest grain yield response of 358 kg ha-1 (37%) when inoculated with Biosoil Nitro+ followed by Serenut 2T that gave the grain yield response of 314 kg ha-1 (31%) when inoculated with the Mak-Bio-Fixer. From this study, there was low abundance of native Bradyrhizobia in Tororo and and MUARIK soils and Serenut 5R and Serenut 2T positively responded to inoculation with better responses recorded in Tororo than in MUARIK and also better responses were recorded with the Nitro BioSoil Nitro+ than the Mak-bio-fixer. It is therefore recommended to inoculate groundnut with the Mak-Bio-Fixer and Biosoil Nitro+ commercial bio-fertilizers in Uganda.