Agronomic and symbiotic performances of common bean varieties inoculated with Rhizobium species under nitrogen fertilizer

Abstract

Common bean [Phaseolus vulgaris (L)] is an important source of income and protein for farmers in developing countries, including Ethiopia. However, inadequate information about agronomic practices, especially the use of N-source fertilizers, limits its production and productivity. Because of this, a field experiment was conducted in the Meskan district during the 2018 cropping season to evaluate the effect of bio/inorganic fertilizers on growth, nodulation, yield, and yield components of common bean varieties. Factors studied included four common bean varieties [Hawassa Dume, Gegeba, Rori, and Ibado], and four levels of bio/inorganic fertilizers [Control, inoculation with Rhizobium strain HB-429, 46 kg N ha^-1, inoculation + 46 kg N ha^-1]. The experiment was laid out in a randomized complete block design in factorial arrangements with three replications. The results showed significant varietal differences in crop phenology, growth, nodulation, yield, and yield components. Hawassa Dume exhibited superior growth, nodulation, and yields among the varieties except for the hundred seed weight. Similarly, the application of bio/inorganic fertilizers showed significant effects on most studied plant parameters. A higher number of pods plant^-1, seeds pod^-1, and grain yield were recorded from the combined application of Rhizobium strain HB-429 + 46 kg N ha^-1. The interaction effect of bio/inorganic fertilizers with varieties significantly affected nodule number plant^-1 and straw yield. The highest nodule number plant^-1 and straw yield were recorded from the Rhizobium inoculation, and the combined application of Rhizobium strain HB-429 inoculation+46 kg N ha^-1 with variety Hawassa Dume. Grain yield was positively and significantly correlated with plant growth, nodulation, and yield-related parameters. Based on the current findings, the combined application of Rhizobium strain HB-429 + 46 kg N ha^-1 was found to be suitable for the common bean variety Hawassa Dume production in the study site and similar agro ecological areas.