Geographic variations in the flowering and ripening behaviors of amphicarpaea edgeworthii benth

Abstract

Strains of yabumame (Amphicarpaea edgeworthii Benth.), an edible resource of geocarpic wild legume, were collected from various stands in Japan and grown to investigate the geographic variations in its flowering and ripening behaviors. Northern strains needed fewer days after sowing to flower. The flowering period lasted longer for northern strains, where the duration varied among strains. Significantly negative correlation existed between days after sowing to flowering and flowering duration. The average 1,000-seed weight including all strains was 22 g for aerial seeds and 143 g for subterranean seeds. The former was a hard seed since scratching the seed coat increased the germination percentage sharply, whereas the latter germinated at high percentage without any pretreatment. The 1,000-seed weight did not correlate with the latitude of home habitat. Subterranean pod including 2 mature seeds, twin bean, was produced at a higher probability in the case of the strains which had a heavier 1,000-seed weight. The degree of subterranean seed to the total of its number and weight correlated vaguely to the latitude of each strain's home habitat. The deviation of the rate among strains was wider in southern strains.