Impact of environmental factors on saffron flowering period in Morocco

Abstract

This research investigates the relationship between climatic variables, altitude and saffron flowering periods, toward predicting the flowering time in saffron as to assist scheduling harvest practices. The study was conducted over 4 years, from 2005 to 2009. Simple predicted models based on some climatic data, occurring during the previous month to critical flowering periods, first flowering date and peak or maximum of flowering, were computed. Four highly significant linear regressions were identified for the two critical dates. The first one include solar radiation and rainfall (R2=1, P‹0.05), and the second one is based on GDD (growing-degree-day) and rainfall (R2=0.99, P‹0.05). The maximum flowering date showed a high correlation with GDD cumulated over the period from 1 to 20 of October (R2=0.998, P‹0.001) for the first model and the solar radiation for the second model (R2=1.000, Pr›0.002). The altitude highly influences the flowering period. A high negative relationship was then observed (R2=-0,76, p‹0.001). Noticing the high year-to-year variability of flowering happenings in the same location and in different altitudes, the models presented could provide an approximate estimation of the flowering dates based on local climatic data and altitude which has to be included in subsequent predictive models.