Multi-trait plant probiotic bacteria improved growth and nutrient uptake of potato (Solanum tuberosum L.) varieties in Eastern Ethiopia

Mobilizing multi-functional plant probiotic bacteria in the rhizosphere plays a significant role in improving soil fertility and sustainable agricultural production and productivity. This study assessed the effect of selected plant probiotic bacteria (PPB) on the growth and nutrient uptake of three potato varieties (Bete, Gudene, and Bubu) under greenhouse condition. The experiment was arranged in a completely randomized design with seven species of probiotic bacteria: Providencia rettgeri, Enterobacter aerogenes(Kleb.mobilis), Raoultella planticola/ornithicola, Lysinibacillus sphaericus, Serratia marcescens ss marcescens, Lysinibacilus fusiformis, and Bacillus Flexus. and four replicates. The findings revealed that inoculated plant probiotic bacteria improved the surrogate agronomic character of potato varieties by 20-40%, with Providencia rettgeri and Lysinibacillus fusiformis demonstrating best performance. Following innoculation of plant probiotic bacteria, the Bete variety showed to have better number of tubers (TN) and root growth (RDW) than the Bubu and Gudene varieties. Inoculation of potato varieties with Lysinibacillus fusiformis improved average plant and tuber biomass by 30%, followed by Providencia rettgeri(20%). All isolates significantly increased Bete’s tuber N, P, and Fe nutrient content by 76.17%, 72.59%, and 65.44%, respectively. Inoculation of potato varieties with Lysinibacillus fusiformis and Raoultella planticola/ornithinolytica improved nutrient uptake of potato shoots and tuber by 60% and the Bete variety responding better to inoculation.The study also found that shoot dry weight, tuber dry weight, dry matter content, and root dry weight positively correlate with plant growth promotion characteristics. Generally, this study evidenced that the PPB isolates have the potential as bio-inoculants for potato varieties. However, the isolates have to be further testedunder field conditions for subsequent evalutation.