Integrating Genomics, Physiology, and Field Experiments for Modeling Crop Water Deficits in Winter Wheat.

Ecophysiological models are necessarily greatly simplified abstractions of complex plant systems. Given the large number of genotypes that exist, and continue to be developed, determining plant parameters for these models has been difficult. Serious challenges also exist for quantifying phenotypic plasticity in whole-plant ecophysiological models based on genomic knowledge and how genes respond to varying environments. Additional complications arise in that phenotypic plasticity varies among genotypes (i.e., the ever-present genotype by environment interaction). With the explosion of information (noise?) coming from genomic and molecular biology work, plant physiology, and general agronomy, much potential exists to help with model parameterization and characterizing phenotypic plasticity. Various efforts are underway to begin to meet this potential, often examining traits that are relatively well understood genetically and controlled by a few genes. Complex traits related to whole-plant response to varying water deficits seem more intractable as gaps in our genomic and physiological knowledge limit our understanding. The objectives of this paper are to: 1) provide observations from field experiments where 24 winter wheat (Triticum aestivum L.) genotypes are grown under varying levels of water deficits, and 2) explore possibilities for how we might better integrate genomic information into our crop models. A case study examining how wheat semi-dwarfing genes respond to varying soil water availability will be presented.