Projects

Crop responses to global increase in evaporative demand: opportunities for improving yields in a dryer world

VPD increase

Global increases in vapor pressure deficit (VPD) or 'atmospheric drought' are driving yield decreases in several key production environments across the globe. One way to mitigate such penalties is to design crop cultivars that either conserve water as VPD increases (drought-prone environments) or overcome unnecessary restrictions to crop water use under high VPD (well-watered environments). However, the genetic basis of such traits and where to precisely deploy them (geographically) remains unknown, resulting in a major bottlenecks to improving yields under climate change. In this research, we address this challenge by combining eco-physiological dissection, physiological phenotyping of mapping populations and crop simulation modeling.

Funding: NSF, CRDF GLOBAL, Minnesota Wheat Research & Promotion Council, Minnesota Soybean Research & Promotion Council | Collaborators: Aaron J Lorenz & Robert M Stupar (soybean breeding), James A Anderson & Brian J Steffenson (wheat breeding), Thomas R Sinclair (crop modeling). 

representative publicationS

Monnens, D., and W. Sadok. 2020. Whole-plant hydraulics, water saving, and drought tolerance: a triptych for crop resilience in a drier world. Annual Plant Reviews Online (in press)

Sadok, W., Schoppach, M.E. Ghanem, C. Zucca, and T.R. Sinclair. 2019. Wheat drought-tolerance to enhance food security in Tunisia, birthplace of the Arab Spring. European Journal of Agronomy, 107: 1–9.

Tamang, B.G., R. Schoppach, D. Monnens, B.J. Steffenson, J.A. Anderson, and W. Sadok. 2019. Variability in temperature-independent transpiration responses to evaporative demand correlate with nighttime water use and its circadian control across diverse wheat populations. Planta, 250 (1): 115–127.

Sadok, W. and B.G. Tamang. 2019. Diversity in daytime and nighttime transpiration dynamics in barley indicate adaptation to drought regimes across the Middle-East. Journal of Agronomy and Crop Science, 205(4): 372–384.

Sadok, W. and R. Schoppach. 2019. Potential involvement of root auxins in drought tolerance by modulating nocturnal and daytime water use in wheat. Annals of Botany, 124 (6): 969–978.

Schoppach, R., D. Fleury, T.R. Sinclair and W. Sadok. 2017. Transpiration sensitivity to evaporative demand across 120 years of breeding of Australian wheat cultivars. Journal of Agronomy and Crop Science, 203(3): 219–226.           

Schoppach, R., J.D. Taylor, E. Majerus, E. Claverie, U. Baumann, R. Suchecki, D. Fleury and W. Sadok. 2016. High resolution mapping of traits related to whole-plant transpiration under increasing evaporative demand in wheat. Journal of Experimental Botany, 67 (9): 2847–2860.

Nocturnal transpiration in crops: magnitude, genetic variability and response to nighttime warming 

Nighttime5

Global warming is taking place more aggressively during the nighttime. In fact, nighttime temperatures are rising at a rate that is 1.4 times that of daytime temperatures. Such warming is likely to be associated with increases in nighttime evaporative demand, which induces seemingly 'wasteful' nighttime water losses through transpiration. Because no photosynthesis occurs during the night, high nocturnal transpiration could be aggravate the severity of drought events. The goal of this research is to quantify the extent of nighttime transpiration in crops, its mechanistic basis and its relationship to yield under various water availability regimes. 

Funding: Minnesota Wheat Research & Promotion Council, Minnesota Soybean Research & Promotion Council, University of Minnesota | Collaborators: Thomas R Sinclair (crop modeling), Krishna SV Jagadish (heat stress and grain development)

representative publicationS

Sadok, W. and S.V.K. Jagadish. 2020. The hidden costs of nighttime warming on yields. Trends in Plant Science (in press)

Schoppach, R, T.R. Sinclair and W. Sadok. 2020. Sleep tight and wake-up early: nocturnal transpiration traits to increase wheat drought tolerance in a Mediterranean environment. Functional Plant Biology (in press)

Sadok, W, J. López, Y. Zhang, B.G. Tamang, and G. Muehlbauer. 2020. Sheathing the blade: significant contribution of sheaths to daytime and nighttime gas exchange in a grass crop. Plant, Cell and Environment (in press)

Tamang, B.G., R. Schoppach, D. Monnens, B.J. Steffenson, J.A. Anderson, and W. Sadok. 2019. Variability in temperature-independent transpiration responses to evaporative demand correlate with nighttime water use and its circadian control across diverse wheat populations. Planta, 250 (1): 115–127

Tamang, B.G., and W. Sadok. 2018. Nightly business: links between daytime canopy conductance, nocturnal transpiration and its circadian control illuminate physiological trade-offs in maize. Environmental and Experimental Botany,148: 192–202.  

Claverie, E., F. Meunier, M. Javaux, and W. Sadok. 2018. Increased contribution of wheat nocturnal transpiration to daily water use under drought. Physiologia Plantarum, 162(3): 290–300.  

W. Sadok. 2016. The circadian life of nocturnal water use: when late night decisions help improve your day. Plant, Cell and Environment, 39(1): 1–2

 

The physiological basis of freezing tolerance in winter crops grown in northern climates 

barley cold2

Enhancing winter hardiness of emerging Minnesota-grown crops such as barley and pea is critical to diversifying cropping systems of the upper Midwest and to sustain vibrant local industries such as plant protein- and beer-making. So far, phenotypic selection via survival rates is the only viable approach to breeding. The goals of this project are to identify ecophysiological traits that are associated with freezing survival and to use such traits to develop a phenotyping pipeline to support barley and winter pea breeding programs for enhanced winterhardiness.

Funding: Minnesota Department of Agriculture-Forever Green Initiative | Collaborators: Kevin P Smith & Brian J Steffenson (barley breeding), Gary J Muehlbauer (barley genomics), Aaron K Lorenz (pea breeding), Robert M Stupar (pea genomics). Photo Credit: Brian Steffenson.

representative publication

Wiering, N.P., C. Flavin, C.C. Sheaffer, G.C. Heineck, W. Sadok, and N.J. Ehlke. 2018. Winter hardiness and freezing tolerance in a hairy vetch collection. Crop Science, 58 (4): 1594–1604.

 

The physiological and genetic bases of heat stress tolerance in oat

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Minnesota is also subject to heat stress in the summer. Evidence shows that historical increases in temperature during the summer drove yield decreases of locally grown oat, which prompted growers to look for more profitable crops such as corn and soybean. This project aims at identifying oat heat stress tolerance traits and genetic markers that will be leveraged in an ongoing breeding program to release more resilient oat varieties towards heat stress events that are expected to increase in frequency and intensity in Minnesota.

Funding: Minnesota Department of Agriculture | Collaborator: Kevin P Smith (oat breeding). Photo Credit: José López.

representative publication

Sadok, W. and S.V.K. Jagadish. 2020. The hidden costs of nighttime warming on yields. Trends in Plant Science (in press)

 

Parsing the environmental and physiological drivers of inter-annual yield depression in intermediate wheatgrass

Kernza2

Intermediate wheatgrass is a new perennial grain crop that is currently being domesticated across Minnesota and the U.S. This crop holds promise thanks to its numerous ecosystem services in additional to its ability to produce food-grade seeds. However, a challenge with this new crop is that it exhibit a large yield depression particularly following the first year, which may decrease its attractiveness to risk-averse farmers. The goal of this program is to identify the environmental and physiological drivers of this phenomenon, as an approach to inform breeding and agronomics programs to enable minimizing this interannual yield decline.

Funding: Minnesota Department of Agriculture-Forever Green Initiative | Collaborators: Jacob Jungers (intermediate wheatgrass agronomics), James A Anderson (intermediate wheatgrass breeding). Photo Credit: University of Minnesota.