Degree Days to 50% Flowering for 12 Cultivars of Spring Canola-Like Mustard

Abstract

Modeling efforts for simulating canola have been based on growth parameters previously established in the Northern Great Plains. However, with advances in canola (Brassica sp.) genetics, establishing parameters for newly developed cultivars are essential for the best modeling projections. Accurate simulation of crop phenology, especially flowering dates, is critical for determining the duration of vegetative growth and when seed yield is most sensitive to stress. If measured flowering dates are not available, process-based models can be used to predict the flowering time based on available temperature data. In the present study, the predicted flowering date was compared to actual measured flowering data. The summed degree days (SDDs) to 50% flowering (hereafter referred to simply as “flowering”) were collected from twelve different types of cultivars planted across multiple locations. For each location predicted SDDs were computed based on temperature data from planting to the date of flowering. The measured and predicted data showed a similar pattern for SDDs to flowering for all cultivars, except for three.  Thus SDDs to flowering were relatively stable across a wide range of latitudes. Furthermore, the SDDs for most cultivars were similar to the potential heat unit sum (450) previously established for Brassica rapa (Polish canola).