Use of hydraulic traits for modeling genotype‐specific acclimation in cotton under drought

Diane R Wang,Martin D Venturas,Douglas J Hunsaker,Kelly R Thorp,Duke Pauli,Michael A Gore,D Scott Mackay

doi:10.1111/nph.16751

Abstract

Summary Understanding the genetic and physiological basis of abiotic stress tolerance under field conditions is key to varietal crop improvement in the face of climate variability. Here, we investigate dynamic physiological responses to water stress in silico and their relationships to genotypic variation in hydraulic traits of cotton (Gossypium hirsutum), an economically important species for renewable textile fiber production.In conjunction with an ecophysiological process‐based model, heterogeneous data (plant hydraulic traits, spatially‐distributed soil texture, soil water content and canopy temperature) were used to examine hydraulic characteristics of cotton, evaluate their consequences on whole plant performance under drought, and explore potential genotype × environment effects.Cotton was found to have R‐shaped hydraulic vulnerability curves (VCs), which were consistent under drought stress initiated at flowering. Stem VCs, expressed as percent loss of conductivity, differed across genotypes, whereas root VCs did not. Simulation results demonstrated how plant physiological stress can depend on the interaction between soil properties and irrigation management, which in turn affect genotypic rankings of transpiration in a time‐dependent manner.Our study shows how a process‐based modeling framework can be used to link genotypic variation in hydraulic traits to differential acclimating behaviors under drought.

Highlights

Rising incidence of extreme drought and heat events in combination with diminishing freshwater resources associated with climate change threatens the global security of plant-based food, fiber and feed production (Coumou & Rahmstorf, 2012; Elliott et al, 2014; Foster et al, 2015; Lesk et al, 2016)
Clay had the highest coefficient of variation across grid cells compared to sand or silt (Table S3), and so it was used as the determinant to select contrasting cells, each composed of 10 plots (Table S4)
There were no significant differences in root vulnerability curves (VCs) parameters across genotypes (P > 0.05 for each parameter; oneway analysis of variance), there were for genotype-specific curves of stems; we report significant differences in the b parameter and Pressure at 50% loss of conductivity (P50) for stem curves (P = 0.003 and 0.007, respectively)

Summary

Introduction

Rising incidence of extreme drought and heat events in combination with diminishing freshwater resources associated with climate change threatens the global security of plant-based food, fiber and feed production (Coumou & Rahmstorf, 2012; Elliott et al, 2014; Foster et al, 2015; Lesk et al, 2016). Despite strong interest in developing crop cultivars that are resilient to water deficit, there remain many challenges to breeding and deployment of such varieties (Atlin et al, 2017). Across years and sites, managed drought trials vary in the frequency and amount of precipitation, soil texture and its related water transport characteristics, and other environmental factors such as solar radiation, temperature, and wind speed. These parameters affect processes that drive the dynamic perception and response of plants to water deficit (Campbell & Norman, 2012), and varieties considered tolerant in one set of conditions may underachieve in others. The meaning of ‘drought tolerance’ is incomplete without adequate understanding of its environmental context: soil, weather, and management (Tardieu, 2012)

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Discussion

Conclusion