Predicting growth and development of pigeonpea: flowering response to photoperiod

Data from sowing-date and other experiments conducted for nine cultivars at three locations ranging from 1 degrees 30'S to 27 degrees 15'N were analysed for photoperiod response. All cultivars were found to have a qualitative response to photoperiod. The results of the analysis show that cultivars previously reported to be "relatively insensitive" to photoperiod were, in fact, highly sensitive. Flowering in short-duration cultivars was delayed by up to a 100 days when daylength in the photoperiod-inductive phase exceeded a critical value. Medium- and long-duration cultivars delayed flowering by over 150 days in response to photoperiod. A model was able to predict this wide range in flowering dates. (C) 2001 Elsevier Science B.V. All rights reserved.