Abstract
The ability to avoid dehydration is a drought resistance mechanism becoming increasingly more important even in temperate regions. In wheat, dehydration avoidance can be associated with a maintained canopy cooling during dry periods. However, in an average year under temperate conditions, drought periods are rather short which makes it difficult to routinely screen for drought avoidance using canopy temperature (CT). Furthermore, confounding factors such as differences in height, shoot biomass, canopy structure and phenology complicate the interpretation of differences in CT. We aimed to use temporal trends in CT and canopy greenness during short-term drought and heat events in the early grain filling phase to circumvent these problems. During this phase, evaporative demand is high and phenology-driven senescence has yet little effect on CT. Diverse sets of 354 and 71 wheat genotypes where grown in the field phenotyping platform of ETH Zurich in 2018 and 2019, respectively. CT was repeatedly measured during early grain filling by means of drone-based imaging. The temporal trends in CT during early grain filling showed a moderate to high within-year heritability (h2 = 0.35 and h2 = 0.88 in 2018 and 2019, respectively). These trends were largely independent of confounding factors when compared to single time point measurements and likely represent genotype-specific reactions to decreasing water availability more directly than absolute CT. CT trends were also largely independent of the temporal trends in stay-green indices. Therefore, we used a combination of time-resolved CT and stay-green trends to identify genotypes combining both traits. Significant differences were observed in the combined time-resolved index among three replicated check varieties. We therefore propose to use the combined time-resolved index to identify genotypes with improved drought avoidance and functional stay green.
Highlights
Drought is a major factor limiting wheat (Triticum aestivum L.) pro ductivity in rain-fed production systems around the world
Measured canopy temperature (CT) co-varied with air temperature but exceeded air tem perature by about 10 degrees (Fig. 3)
As air temperature is a constant subtracted from all measured canopy temperatures, the size and direction of this offset is irrelevant in the context of this study
Summary
Drought is a major factor limiting wheat (Triticum aestivum L.) pro ductivity in rain-fed production systems around the world. In Europe, increased climatic variability, in particular the occurrence of heat and drought in high-yielding regions, has recently counter-balanced genetic progress in yield potential (Bris son et al, 2010; Oury et al, 2012). As a result of climate change, heat and drought periods are predicted to further increase both in frequency and in severity (Calanca, 2007; Lehner et al, 2006; Trnka et al, 2015). In regions with predictable early-season rainfall, heat and drought occurring during the late growing season may be ‘escaped’ by speeding up crop phenology (Shavrukov et al, 2017). Developmental adaptation will have to be complemented with genetic progress in plant performance under heat and drought stress (Lobell et al, 2011; Tester and Langridge, 2010)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
