Published online by Cambridge University Press: 03 October 2008
Various sequences of different daylength regimes were given to five potentially tropically-adapted soyabean and three cowpea cultivars, to establish the duration of the photoinductive period which is necessary for their subsequent satisfactory development for experimental trials in the U.K. in long summer days. Genotypic differences in response to photoperiodic delay of flowering were clearly distinguished, but unless these soyabean and cowpea cultivars were kept in short photoperiods for at least 49 days, flower retention and pod development were adversely affected when they were subsequently planted in natural U.K. long summer days. The developmental stages from juvenility to flowering are discussed.