title: Review: An integrated framework for crop adaptation to dry environments: Responses to transient and terminal drought.
abstract: As the incidence of water deficit and heat stress increases in many production regions there is an increasing requirement for crops adapted to these stresses. Thus it is essential to match water supply and demand, particularly during grain-filling. Here we integrate Grime's ecological strategies approach with traditional drought resistance/yield component frameworks describing plant responses to water deficit. We demonstrate that water use is a function of both short and longer term trade-offs between competing demands for carbon. Agricultural crop adaptation is based on escape. Rapid growth rates and high reproductive investment maximize yield, and stress is avoided through a closely regulated, climate-appropriate annual phenology. Crops have neither the resources nor morphological capacity to withstand long periods of intense water deficit. Thus, under terminal drought, yield potential is traded off against drought escape, such that drought postponing and/or tolerance traits which extend the growing season and/or divert source from reproductive sinks are maladaptive. However, these traits do play a supporting role against transient water deficits, allowing longer season cultivars to survive by mining water through deeper roots, or restricting transpiration. Recognizing these trade-offs made within escape-strategy limits will allow breeders to integrate complementary adaptive traits to transient and terminal water deficits.
authors.affiliation: CSIRO Agriculture, Private Bag No. 5, Wembley, WA 6913, Australia. Electronic address: Jens.Berger@csiro.au.
authors.forename: Jens
authors.initials: J
authors.lastname: Berger
authors.affiliation: CSIRO Agriculture, Private Bag No. 5, Wembley, WA 6913, Australia.
authors.forename: Jairo
authors.initials: J
authors.lastname: Palta
authors.affiliation: ICRISAT, Crop Physiology Laboratory, Patancheru, 502 324 Telangana, India.
authors.forename: Vincent
authors.initials: V
authors.lastname: Vadez
mesh_terms: D000222:Adaptation, Physiological; D018556:Crops, Agricultural / Q000502:physiology*; D055864:Droughts; D013312:Stress, Physiological; D014867:Water / Q000502:physiology*
chemical_list: D014867:Water
keywords: Crop adaptation; Drought escape/postponement/tolerance; Trade-offs; Transient and terminal water deficits