Developing a Growth Model to Predict Dry Matter Production in Broccoli (Brassica oleracea L. var. italica) ‘Ohayou’

Abstract

The demand for broccoli (Brassica oleracea L. var. italica) is increasing for use as fresh produce and for use in the processing industry. Therefore, growth prediction technology is required for its stable production. In this study, several cultivations of experiments were conducted to clarify the critical characteristics of the parameters needed to predict the growth of broccoli in a dry matter production model. The extinction coefficient was determined based on the leaf area index and intercepted solar radiation rate. Radiation-use efficiency was demonstrated using a linear function of the accumulated solar radiation intercepted amount and the total dry weight above-ground. The distribution of dry matter to the head and stem was indicated by the sigmoid function of the accumulated average temperature. The dry matter percentage of the leaf, dry matter percentage of the head and stem, and the ratio of leaf area to the fresh weight of the leaf were represented by a power function with dry weight above-ground. The fresh weight above-ground (R² = 0.92) and the fresh weight of the head and stem (R² = 0.98) were highly correlated with the estimated and observed values. Verification was performed using the developed growth model. As a result, the error between the harvest date and the predicted harvest date could be forecasted to within 4 days and the error in the fresh weight of the head could be predicted with an accuracy of −0.3 ~ +7.7 g·plant⁻¹.