In vitro plant regeneration from seed explants of wild groundnut species (Genus Arachis, Section Extranervosae)
In vitro regeneration of wild groundnut species from Section Extranervosae (Arachis villosulicarpa, A. macedoi, A. retusa, A. burchellii, A. pietrarellii, A. prostrata, A. aff. prostrata and a new species) was examined for the purpose of germplasm renewal and conservation. Seeds of different ages, stored at the seed bank of CENARGEN/EMBRAPA were either inoculated on culture medium or used as a source of embryo axis and cotyledon explants. Whole seeds failed to germinate on MS either without growth regulators (MS0) or supplemented with 10 μM TDZ. Embryo axes cultured on MS0 produced only single plants. In the presence of 8.8 μM BAP these explants showed multi-shoot formation. Cotyledons cultured on MS supplemented with 110 μM BAP developed adventitious shoots through direct organogenesis. Plant regeneration was obtained from A. villosulicarpa, A. macedoi, A. retusa, A. burchellii and A. pietrarellii both from embryo axes and cotyledons. Explants from A. prostrata and A. aff. prostrata did not produce regenerants. Rooting of shoots was induced in the presence of 5.4 μM NAA. Primary plants derived from these explants were further multiplied by culturing nodal segments on MS medium plus 2.7 μM NAA.