Abstract

Increasing yield resiliency to water deficits remains a high priority for crop improvement. Two facts are often overlooked when considering the yield benefit of a plant trait modification. (1) The total amount of water available to a crop through a growing season ultimately constrains growth, and yield cannot exceed what is possible with the limited amount of available water. (2) Soil water content is always changing over time so plant response needs to be considered within a temporally dynamic context of day-to-day variation in soil water status. Many previous evaluations of drought traits have implicitly considered water deficit from a ‘static’ perspective. While the static approach of stable water-deficit treatments is experimentally congruous, the results are not realistic representations of real-world drought where soil water levels are always changing. The response to trait modification depends on the temporal dynamics of soil water content through the growing season.  Consequently, no trait always results in a positive response under all drought scenarios. In this seminar, I will focus on the sensitivity of crop growth and yield to atmospheric vapor pressure deficit (VPD) and a water conservation trait resulting in partial stomata closure at elevated VPD and its possible implication in breeding programs.