Large‐scale characterization of drought pattern: a continent‐wide modelling approach applied to the Australian wheatbelt – spatial and temporal trends

TLDR

Plant responses to drought are complex, so traits adapted to one drought type can be disadvantageous in another, making it essential to identify which drought types to target for crop improvement. The study proposes using environment characterization to guide breeding and research toward germplasm, traits, and genes suited to target drought environments. The authors modeled seasonal drought patterns across the Australian wheatbelt using 123 years of weather data for multiple locations and managements, simulated maturity effects with two additional genotypes, and applied the method continent‑wide, enabling extension to other crops and drought‑prone regions. Four major drought environment types were identified, with severe pre‑flowering stress occurring in 44 % of cases, relief during grain filling in 24 % or 20 %, high inter‑annual and regional variability, and all four types present across most seasons, locations, management systems, and genotypes.

Abstract

Summary Plant response to drought is complex, so that traits adapted to a specific drought type can confer disadvantage in another drought type. Understanding which type(s) of drought to target is of prime importance for crop improvement. Modelling was used to quantify seasonal drought patterns for a check variety across the Australian wheatbelt, using 123 yr of weather data for representative locations and managements. Two other genotypes were used to simulate the impact of maturity on drought pattern. Four major environment types summarized the variability in drought pattern over time and space. Severe stress beginning before flowering was common (44% of occurrences), with (24%) or without (20%) relief during grain filling. High variability occurred from year to year, differing with geographical region. With few exceptions, all four environment types occurred in most seasons, for each location, management system and genotype. Applications of such environment characterization are proposed to assist breeding and research to focus on germplasm, traits and genes of interest for target environments. The method was applied at a continental scale to highly variable environments and could be extended to other crops, to other drought‐prone regions around the world, and to quantify potential changes in drought patterns under future climates.