Abstract: The goal of this study was to assess how the faba bean responded to the inoculation of six indigenous rhizobial isolates in acidic field conditions at Damotu (in 2019) and Chiri (in 2020) in the Ejere district, Ethiopia. We laid out the experiments in a randomised complete block design (RCBD) with three replications and a plot size of 4 m x 3 m. The treatments consisted of six indigenous faba bean rhizobia isolates designated as FB-NS-02, FB-NS-03, FB-EM-02, FB-EM-05, FB-EM-07, and FB-EM-11. Additionally, we included a positive control that received 18 kg ha1 of urea and a non-inoculated negative control. The results revealed a significant difference (p ≤ 0.05) between treatments on aboveground biomass, grain, and haulm yields. The inoculation of rhizobial isolate FB-EM-11 at both experimental sites yielded the highest grain yields (3378.3 kg ha-1 and 3286.7 kg ha-1). Rhizobial isolates FB-NS-03 (3376.7 kg ha-1) at Damotu and FB-EM-07 (3269.5 kg ha-1) at Chiri yielded the second highest grain yields. Based on the two successive years’ grain yield responses, FB-EM-11 (3332.6 kg ha-1) and FB-NS-03 (3198 kg ha-1) were the first and second most performing isolates at Ejere district, respectively. Thus, these rhizobial isolates are the most promising candidates for the development of commercial faba bean rhizobial inoculants in acid-prone areas of Ethiopia.
Keywords: Central Highlands, Faba bean, inoculant, soil acidity, yield