Ndiang Zenabou^1,, Semboung Lang Firmin¹, Ngo Nkot Laurette¹, Wafo Fosso Daniel¹, Tchinda Ninla Laurianne¹, Bell Joseph Martin²

Vigna subterranea (L.) Verdc., which is the third most important food legume in terms of production and consumption after peanuts (Arachis hypogeae L.) and cowpeas (Vigna unguiculata Walp.) with a very high nutritional value, remains a neglected and underutilized specie. Some morphotypes of Bambara groundnut were surveyed in order to constrain their nodulation potential six weeks after sowing. Nodules of fifteen plants per morphotype per replication were determined under pot experiment in non-sterile soil in Yaounde. The effectiveness of N-fixation was determined by measuring the above-ground plant size (PH) and biomass (SDW). All plants nodulated. Nodule number (NN = 11 - 108), nodule dry weight (NDW = 0.04-0.26 g), shoot height (SH = 20.48 - 30.96 cm), root length (RL = 34.6 - 52.1 cm), shoot dry weight (SDW = 2.45 - 7.08 g) and root dry weight (RDW = 0.34 - 1.28 g) vary from one morphotype to another. NN correlated positively and highly to the RDW (r = 0.75; p < 0.001) and NDW (r = 0.89; p < 0.001) revealing the root biomass as an indicator of good nodulation. SDW correlated positively and highly to the RDW (r = 0.70; p < 0.001) too, showing that the root biomass resulted from a good shoot system as NOR2Y morphotype. SDW shows positive and imperfect correlation with NDW (0.41) and NN (0.32) indicating that shoot biomass was not always the result of good nodulation. The nodulation potential of studied Bambara groundnut evidences their infectivity by indigenous rhizobacteria. It seems to be a good criterion for predicting high productive species and a selection marker for breeding programs.

morphotypes, nodules, plant biomasses, Vigna subterranea