Tritordeum, barley landraces and ear photosynthesis are key players in cereal resilience under future extreme drought conditions

16 páginas, 9 figuras

Drought is the main factor limiting cereal production in the Mediterranean basin and Climate Change will exacerbate its effects. Among the strategies to mitigate Climate Change impact on cereal production, we highlight the development of drought-resilient crops better adapted to future extreme conditions, either by i) using heritage germplasm (e.g., landraces) or ii) developing novel species (e.g., crop hybrids). Our study aimed to identify key functional traits and stress-tolerant germplasm to contribute to designing drought-resilient crops under future Mediterranean climatic conditions. For that, we conducted an innovative approach combining a late-sowing field trial with two contrasting water regimes to simulate future extreme drought conditions, the use of high-throughput phenotyping devices and an infrared gas analyser to characterise leaf and ear photosynthesis, biochemistry, growth, and stress responses during the reproductive stage, and a novel linear mixed-effects model to integrate these results with final agronomical data. Modern durum wheat and barley, barley landraces and tritordeum varieties were grown and evaluated as individual plants. Our results identified barley landrace SBCC010 and tritordeum Coique as promising resilient germplasm. These genotypes showed a grain set maintenance and a higher allocation of resources to the ears compared to modern varieties, higher leaf and ear greenness, and ear photosynthesis and thermostability during the reproductive stage, particularly under stress conditions. We conclude the necessity of including ear photosynthesis in the breeding programs relying on adaptive germplasm as barley landraces and novel cereal hybrids as tritordeum to design drought-resilient cereals for future extreme Mediterranean environments.

This study was funded by the FCT – Fundaçao para a Ciencia e a Tecnologia, I.P., through the GREEN-IT –Bioresources for Sustainability R&D Unit [Base funding, UIDB/04551/2020 and Programmatic funding, UIDP/04551/2020], and the LS4FUTURE Associated Laboratory (LA/P/0087/2020), as well as by the Basque Government through the grant GRUPO Gobierno Vasco-IT1682-22. A.Y.A. was the recipient of a postdoctoral fellowship funded by the Basque Government, and A.A was the recipient of a predoctoral fellowship from the same institution. R.V. and O.V.D. were supported by FCT through the Program “Concurso de Estímulo ao Emprego Científico” [CEECINST/00102/2018/CP1567/ CT0039 to R.V. and 2022.07839.CEECIND/CP1725/CT0022 to O.V.D.] and by the Spanish Ministry of Science, Innovation and Universities through a Ramon y Cajal research contract (RYC2022-037887-I to R.V.). R.V. also acknowledge support from the Scientific Network “WheatNet”, funded by the Spanish National Research Council (CSIC).

Peer reviewed