In vitro Regeneration of Two Local Bambara Groundnut Landraces [Vigna subterranea (L.) Verdc.] in Kenya

Bambara groundnut [Vigna subterranea (L.) Verdc.] is a climate-resilient and nutrient-dense legume with limited genetic improvement in Kenya due to the absence of efficient in vitro regeneration systems. This study evaluated regeneration responses of two Kenyan landraces, Cream with Black Eye and Yellow with White Eye, using different explant sources and plant growth regulator regimes. Callus induction was achieved in all explants, with frequencies reaching 100% under 2,4-dichlorophenoxyacetic acid and 50-100% under naphthaleneacetic acid. Direct shoot regeneration from embryo axes cultured on Murashige and Skoog medium supplemented with 0.25 mg/L 6-benzylaminopurine produced the highest proliferation, yielding mean shoot numbers of 34.8 and 37.2 per explant in the two landraces. No shoot regeneration was observed from callus under any treatment. Rooting frequency reached 80-93% at 0.2 mg/L indole-3-butyric acid. Direct organogenesis proved more reliable than callus-mediated regeneration. These findings establish a reproducible regeneration protocol for Kenyan Bambara groundnut and provide a basis for propagation and future biotechnological applications.