Cardinal Temperatures for Germination in Three Millet Specieses (Panicum miliaceum, Pennisetum glaucum and Setaria italica)

The purpose of this study was to quantify response of germination rate to temperature and to obtain cardinal temperatures in three millet specieses (Panicum miliaceum, Pennisetum galucum and Setaria italica). An experiment was conducted at the Institue de Agricultura Sostenible (CSIC, Cordoba, Spain) from March to August 2004. In this experiment, germination rate (the reciprocals of time to 50% of germination) was calculated at different constant temperatures (ranging from 5 to 45°C, with 5°C intervals). The experiment replicated once again to ensure about accuracy of results from the first experiment. Cardinal temperatures were obtained by fitting a intersected, non-linear regression model to data of germination rate versus temperatures. Results indicated that cardinal temperatures for germination varied slightly between different specieses. The mean of calculated cardinal temperatures (based on data of both experiments) were 9.9°C for base, 40.2°C for optimum and 47.8°C for ceiling temperature in common millet; these estimates were 7.7, 38.9 and 46.0°C for pearl millet and 9.3, 37.0 and 46.0°C for foxtail millet. This information can be used in evaluation of new areas for introduction of these specieses and selection of appropriate sowing date, or other objectives such as prediction of development stages and etc.