A simulation model of climate effects on plant productivity and variability in cauliflower (Brassica oleracea L-botrytis)

The paper describes a model of cauliflower (Brassica oleracea L. botrytis) growth and development under conditions where water and nutrients are not l imiting. The model consists of four linked processes: crop development, lea f area expansion, increase in curd diameter and growth of dry matter. The m odel aims to describe variability between plants in time of curd initiation and harvest. Crop development is described as a function of temperature on ly. Leaf area expansion is described by a logistic function where growth ra te depends on temperature. Temperature and available carbohydrates control the rate of increase in curd diameter. Dry matter assimilation is a functio n of intercepted radiation and of demand for dry matter growth. The assimil ates are distributed among the organs in proportion to their demand. The mo del was calibrated for the cultivar Plana using data from a growth chamber experiment and from a field experiment. A verification of the model against field data showed that the model was able to reproduce variability in curd diameter, indicating that variability in curd size is caused by variabilit y in time of curd initiation. (C) 2000 Elsevier Science B.V. All rights res erved.