This relationship functioned well, particularly on release of drought stress. Both clocks are influenced by temperature and water status, while reproductive development is also influenced by photoperiod. Fitting the standard model for photoperiod response to observed reproductive branching data gave a minimum optimum photoperiod of 15.5 h and a sensitivity of 0.25 h-1, assuming the crop was sensitive to photoperiod from emergence. However, an improved fit was obtained by also assuming branching is inhibited when the rate of change of photoperiod was above 0.01 h d-1. However, the importance of some characters changes under drought, such as the date at which the maximum leaf size occurs.
Further validation is necessary, however, before widespread application.
The factors controlling leaf size and times of branching were identified as areas in which there is a scarcity of knowledge, and to which future cassava physiology research should be directed. The model simulates competition for light, water and nitrogen. The model is still under development and not yet ready for general release.