Quantifying phenotypic plasticity using genetic information for simulating plant height in winter wheat

A challenge for crop simulation modelling is to incorporate existing and rapidly emerging genomic information into models to develop new and improved algorithms. The objective of this effort was to simulate plant height in winter wheat (Triticum aestivum L.) across a range of environments in Nebraska using genetic information. Plant height is influenced by major genes that are discrete and well characterized genetically and phenotypically. Although plant height is a complex trait, it is far simpler than many other traits. Two datasets were used in this study, one from a study where final plant heights were measured at five locations across Nebraska in two years (dataset 1) and another study where plant height was measured 13 times before anthesis in one year at one location for one genotype (dataset 2). The crop simulation model CropSyst was modified by incorporating a different phenology algorithm and adding a plant height algorithm. The plant height algorithm was based on the ratio of the mean optimum final height of a height class (tall semi-dwarf, semi-dwarf, short semi-dwarf) to the mean optimum final heights for two tall cultivars, an environmental index based on the fraction of transpirable soil water, and the development stage. Final plant heights were simulated reasonably well for the different height classes with a root mean square error (RMSE) of 7.3 cm (dataset 1). For dataset 2, the simulated plant height of a short semi-dwarf line was always greater than the observed plant height, resulting in observed and simulated final plant heights of 82 and 88 cm, respectively (RMSE = 8.8 cm). The least accurate simulations, in which heights were overpredicted, occurred when precipitation during the growing season was above average.