Published online by Cambridge University Press: 27 March 2009
In an experiment to determine the effect of photoperiods of 11, 13 and 15 h on the floral development of five determinate varieties of Phaseolus vulgaris it has been shown that long photoperiods bring about the abscission of flower buds on the main axis and secondary branches of three varieties native to South America. On the basis of these results it is concluded that under field conditions it is the long photoperiods of the British summer which are largely responsible for the poor development and eventual abscission of flower buds in these varieties for most of the growing season.