Phenotypic characterization of diverse Bambara groundnut (Vigna subterranea [L.] Verdc.) germplasm collections through seed morphology

Bambara groundnut (Vigna subterranea [L.] Verdc.) is an important grain legume native to Africa. Unlike other legumes, the crop has been largely neglected by science and is part of the so-called neglected and underutilized plant species of Africa. In Africa, farmers currently grow unimproved and heterogeneous landraces in seed mixtures that hold distinctive and divergent genetic attributes. The systematic selection of Bambara groundnut landraces into defined homogenous groups of seed morphotypes for effective breeding would boost crop productivity and quality, and improve food security. Systematic pre-breeding of Bambara groundnut is a starting point to enhance the productivity of the crop. The objective of this study was to characterize a wide range of germplasm of Bambara groundnut collections using seed morphology to classify and identify unique germplasm. Bambara groundnut seed collections (58 seed lots) from seven diverse geographic origins were phenotyped using visual technique to describe seed morphological features including: seed coat colour and pattern, seed eye colour and pattern and hilum colour and pattern. The study generated baseline seed morphology diversity information, and 353 different seed morphotypes of the crop were distinguished for field production of true to type lines and further genetic improvement.