Abstract
Arachis pintoi, a perennial peanut native to Brazil, is well nodulated with native rhizobia although the symbiosis is often ineffective. Since this leguminous plant has great potential as a multipurpose forage and cover crop in soils with low fertility, a study was initiated to select and identify effective Bradyrhizobium strains for A. pintoi. Of 230 authenticated bradyrhizobia isolated mainly from centres of diversity of the genus Arachis in South America, only 48 were effective on A. pintoi, although all the isolates nodulated the two genotypes evaluated. A specific host x strain interaction demonstrated a potential for improving the symbiosis. Under greenhouse conditions, several Bradyrhizobium strains proved competitive with the indigenous microflora and produced more dry matter yield and higher N-fixation rates than the native rhizobia.
