A simple empirical model for predicting development and dry matter partitioning in cauliflower (Brassica oleracea L. botrytis)

An empirical model derived from data of field experiments is presented that predicts development and dry matter partitioning in cauliflower under cond itions of unrestricted nutrient and water supply. The model is a combinatio n of an empirical relationship between temperature sum and leaf number, a v ernalisation model, an allometric approach of dry matter partitioning betwe en leaf and stem and an empirical logistic function describing the fraction of dry matter allocated to the curd depending on the temperature sum after the end of the vernalisation process. This model was incorporated in a sim ple dry matter production model which calculated dry matter production usin g the product of intercepted photosynthetic active radiation and light use efficiency. However, the parameter values light use efficiency and specific leaf area of the model had to be fitted to every experiment in order to ge t an acceptable description of cauliflower dry matter production. Applied t o an independent data set the model was able to predict measurable paramete rs like leaf number (r(2) = 0.73), the proportion of leaf, stem and curd on total dry matter (r(2) = 0.55, 0.08 and 0.77) and the length of the growin g season (r(2) = 0.69). (C) 1999 Elsevier Science B.V. All rights reserved.