Crop modeling suggests limited transpiration would increase yield of sorghum across drought-prone regions of the United States

Abstract

Breeding sorghum for drought adaptation is pivotal to secure crop production in drought-prone regions. Limited transpiration (LT) restricts water demand at high vapor pressure deficit, saving water for use in critical periods later in the growing season. Here we evaluated the hypothesis that LT would increase sorghum grain yield in the United States. We used a process-based crop model, APSIM, which simulates interactions of genotype, environment, and management (G x E x M). In this study, the G component includes the LT trait (GT) and maturity group (GM), the E component entails water deficit patterns, and the M component represents different planting dates. Simulations were conducted over 33 years (1986-2018) for representative locations across the US sorghum belt (Kansas, Texas, and Colorado) for three planting dates and maturity groups. The interaction of GT x E indicated a higher impact of LT sorghum on grain for LD, MD, and ED (8%), than on WW environments (4%). Thus significant impacts of LT can be achieved in western regions of the sorghum belt. Otherwise, the lack of interaction of GT x GM x M suggested that an LT sorghum would increase yield by around 8% across maturity groups and planting dates. Although the interaction GM x M revealed that specific combinations are better suited across geographical regions. Overall, the findings suggest that breeding for LT would increase sorghum yield in the drought-prone areas of the US without tradeoffs.

Practical Considerations and Limitations of Using Leaf and Canopy Temperature Measurements as a Stomatal Conductance Proxy: Sensitivity across Environmental Conditions, Scale, and Sample Size

“…At some critical point, this stomatal closure can restrict the flow of CO 2 into the plant such that rates of photosynthesis, and ultimately growth and yield, are negatively affected, which is commonly termed “water stress.” Some plants possess an adaptation known as the “limited transpiration trait,” which allows them to limit water loss through transpiration at a high vapor pressure deficit (VPD). This trait contributes to early-season water conservation and can ultimately lead to improved yield under drought conditions [ 3 – 5 ]. While there are other nonstomatal factors, such as Rubisco activity and carboxylation efficiency, that can negatively affect plant productivity in the presence of drought [ 6 ], stomatal conductance ( g s ), which quantifies the rate of gaseous exchange between the interior of the leaf and the surrounding air through stomata, is often used as a convenient indicator of the degree to which plant productivity is limited by insufficient water supply or excessive evaporative demand.…”