A TEMPERATURE RESPONSE FUNCTION FOR CORN DEVELOPMENT

Phenological development of corn was studied under field conditions at several locations throughout southwestern Manitoba. Data for 12 location-years were collected from eight sites during 1980-1983. Two early-maturing hybrids ('Pioneer 3995' and 'Northrup King 403') and a medium maturity hybrid ('Pride 1108') were used. A temperature response function that accurately described phenological development under a controlled environment was modified and used to estimate phenological development of field-grown corn. The iterative temperature (IT) model allowed more accurate estimation of the duration from emergence to stem elongation and from stem elongation to silking than corn heat unit (CHU) or growing degree day (GDD) models. The IT model was independent of growth phase duration; this was not the case for CHU and GDD. The model is not suited to hybrid maturity rating, but may be useful for simulation modeling purposes. © 1990.