SIMULATION OF SHOOT VEGETATIVE DEVELOPMENT AND GROWTH OF UNSTRESSED WINTER-WHEAT

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 stimulated 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.