In vitro and genetic diversity studies of twelve accessions of aerial yams (D. bulbifera and D. alata) in Ghana

Aerial yams (D. bulbifera and D. alata) are usually among the dioscoreaceae, in that they are cultivated not only for their tubers but also for the bulbils that develop at the leaf axils of the vine. Twelve accessions collected from five geographic regions were evaluated for morphological characteristics. The results indicate that the 12 accessions exhibited similarity with respect to 11 traits but were variable with respect to 5. Bulbils from the twelve accessions of aerial yams collected from the experimental field, were analysed for proximate composition including moisture, crude protein, crude ash, crude fat, crude fibre and carbohydrate content using the Association of Official Analytical Chemist (AOAC) method. Elemental composition of the bulbils was also determined through instrumental neutron activation analysis (INAA). Accession S recorded the highest crude protein (6.77 %), crude fibre (3.38 %) and carbohydrate (25.39 %) contents. Bulbils from D, G and T recorded the highest crude fat (0.56 %), moisture (72.97 %) and crude ash (7.96 %) content respectively. Accession V recorded the highest amount of magnesium (143.43 mg/100g), potassium (2644.4 mg/100g), chlorine (3272.2 mg/100g) and copper (1.116 mg/100g). Bulbils from accession F also recorded the highest amount of aluminum (5.26 mg/100g) and manganese (0.43 mg/100g), while accession B, C, E and R also recorded highest percentages of vanadium (0.037 mg/100g), sodium (26.63 mg/100g), calcium (333.5 mg/100g) and zinc (4.53 mg/100g) respectively. Nodal explants of 12 accessions of the aerial yam were cultured in vitro on Murashige and Skoog (MS) medium supplemented with varying concentrations of kinetin with or without activated charcoal, as assessed for ability to regenerate plantlets with distinct shoots, leaves and roots. The highest regeneration of plantlets was achieved at kinetin concentration of 2.0 mg/l with activated charcoal. Kinetin concentration beyond 2.0 mg/l proved to be phytotoxic and therefore reduced both shoot and leaf formation. (au)