Botany online 1996-2004. No further update, only historical document of botanical science!
The soybean was cultivated under cycles of 10 h light and 8 - 62 h of darkness.
Ordinate: Number of Flowers. The maxima are at 10 h light and 14 h darkness and at 10 h light and 30 h darkness (Periods of light are symbolized by light blue, periods of darkness by red-violet bars). On the abscissa are 6 h intervals marked. (K. C. HAMNER, 1960)