A MODEL OF EXPANSION AND SENESCENCE OF INDIVIDUAL LEAVES OF FIELD-GROWN MAIZE (ZEA-MAYS L)

Estimation of leaf area is a major component of plant growth models. I n this study, a model was developed to calculate field-grown maize lea f area expansion and senescence on an individual leaf basis. The model began with an equation, based on cumulative growing degree-days from emergence, to initiate leaf area development. The model required daily values of maximum and minimum air temperature, solar radiation and pr ecipitation, had essentially a daily time step with day and night mode s, and could be run on commonly accessible computers (micros to mainfr ames). The objective of the development of the model was to assist pla nt breeders in optimizing leaf number and shape for adaptation to spec ific environments.