A simple phenological model of muskmelon development

Utilizing information gathered in previous growth chamber and field experim ents, we developed a simple temperature-driven crop phenology model of musk melon (Cucumis melo L.) to help commercial growers time crop phenological e vents and predict harvest dates. The model quantifies vegetative developmen t in terms of main vine node numbers which allows the model to simulate eit her a direct-seeded or a transplanted crop. The model operates on an hourly time-step but requires only daily weather data and a few cultivar-specific parameters including plastochron interval and thermal time requirements to reach six predefined developmental stages. The model was tested against an independent data set consisting of three muskmelon cultivars grown at five transplanting dares. Tests of;he model indicate an average ability to pred ict main vine node numbers to within one to two nodes of observed values. E stimated harvest dale predictions were more variable than those for main vi ne node number but an average model accuracy of 1 to 3 d was obtained in mo del tests with a data set used to construct the model. Procedures for calib rating the model for different cultivars, cultural practices or environment s are outlined.