Induced mutations in winged bean (Psophocarpus tetragonolobus L. DC) with low tannin content

Four mutants of winged bean (Psophocarpus tetragonolobus (L.) DC) with altered tannin content were selected among the M3 seeds present on M2 plants following mutagenic treatment of seeds of cvs UPS 122 and Kade 6/16 using gamma radiation from a Co60 gamma source. These mutants were selected from the most chimeric parts of the M1 plant, which had earlier been identified to be the first mature pods on the M1 plant and the earliest formed M2 seeds in the M1 pods. The indirect selection of tannin mutants was based on searching for seed coat colour changes in M3 seeds. Cv UPS 122 yielded the mutants 3/1-10-12 and X22 from 1958 and 1883 M2 plants respectively. Cv Kade 6/16 yielded the mutants 3/9-0-12 and 3/4-10-7 from 1442 and 1011 M2 plants respectively. One of the mutants, 3/4-10-7, which was the only desirable one, had a level of tannin of about 25% of the wild type cv. Kade 6/16. The other three mutants had similar or increased tannin levels.