Efforts to accelerate domestication of winged bean (Psophocarpus tetragonolobus (L.) DC.) by means of induced mutations and tissue culture

This thesis describes mutation breeding and tissue culture techniques developed for accelerated domestication of winged bean ( <em>Psophocarpus</em><em>tetragonolobus</em> (L.) DC.). The tissue culture techniques, which are the first steps towards genetic transformation of the crop, include: (1) direct adventitious shoot formation from the axes of cotyledon explants; (2) direct simultaneous regeneration of adventitious shoots and somatic embryos; and (3) direct somatic embryogenesis on the wounds of cotyledon explants. An optimised mutation breeding technique for economic significance, based on the early selection of chlorophyll mutations generated from gamma-radiated seeds, has been developed. The use of this scheme has resulted in the recovery of seed coat colour mutants which have succesfully served as an indirect method for selecting changes in tannin content and nodulation. A desired mutant with reduced tannin content and improved nodulation was selected