U.S. Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska


Document Type


Date of this Version

January 1991


Published in Ecological Modelling, 53 (1991) 189-204.


Mechanistic crop simulation models can aid in directing research and improving farm management. Recent research on winter wheat (Triticum aestivum L.) canopy development was consolidated into a model of aboveground vegetative development and growth called SHOOTGRO 1.0. The model assumes that water, nutrients, and light do not limit development and growth. Initial conditions of cultivar type (dwarf, semidwarf, mid-tall, and tall), seeding rate, planting depth and date, and latitude are inputs. Daily temperature, expressed as growing degree-days, drives SHOOTGRO 1.0. Processes are simulated with a daily time step. Computer code is standard Fortran 77.

The morphological nomenclature used allows each leaf and node plus associated internode to be identified and their appearance, development, growth, and senescence to be followed from planting through completion of main stem flag leaf growth (shortly before booting). Three cohorts of plants are simulated based on time of emergence. Simulated growth of leaves and internodes is a function of leaf number and accumulation of thermal time, as is leaf senescence.

The model integrates aboveground vegetative development and growth of individual vegetative components into one simulation. SHOOTGRO 1.0 is useful in estimating potential development and growth, and in predicting stage of vegetative development which may be critical in scheduling cultural practices and assisting breeders in selecting traits.