Application of a Model for Prediction of Mulberry Shoot Elongation to Various Regions

Abstract

A model for prediction of shoot elongation was applied to various regions in Japan, and its fitness was evaluated. In the model, the shoot elongation rate in one arbitrary day was decided by the average temperature and photoperiod on that day and shoot length by those on the previous day. Parameters of the model were determined for shoot elongation data of three cultivars ('Ichinose', 'Kairyou-nezumigaeshi' and 'Shin-ichinose') in four prefectures, Miyagi, Fukushima, Ibaraki and Kagoshima. When the maximal shoot elongation rate (PR_max) was determined independently for all prefectures, root mean square errors of the estimated shoot length were about 9 cm for all cultivars. The values fitted by the model represented actual annual fluctuation of shoot elongation well. Estimated values were also in good agreement with the measured data which were not used for determining parameters. Therefore, the model seemed to represent the response of mulberry vegetative growth to temperature and photoperiod.