Breeding soybeans for the tropics capable of nodulating effectively with indigenous Rhizobium spp.

Kueneman, E.A., Root, W.R., Dashiell, K.E. & Hohenberg, J. (1984). Breeding soybeans for the tropics capable of nodulating effectively with indigenous Rhizobium spp. Plant and Soil, 82, 387-396.

Most soybean varieties fail to nodulate effectively in tropical soils unless inoculated with a competitive strain of Rhizobium japonicum. Developing countries in the tropics, with few exceptions, lack inoculant industries to produce and distribute viable inoculants to small farmers and extension programs to teach them to use inoculant. Several soybean genotypes have been identified that nodulate effectively with many strains of the “cowpea” inoculation group which is ubiquitous in tropical soils of Africa. Soybean genotypes that nodulate and grow well without inoculant application are called “promiscuous”. Methodologies for incorporation of the promiscuity character into high-yielding backgrounds are discussed.