Changes in seed composition and germination of wheat (Triticum aestivum) and pea (Pisum sativum) when exposed to high temperatures during grain filling and maturation

International audienceMost studies on the effects of climate change have been conducted on grain yield and composition; few havefocused on seed germination and storage ability, especially in temperate crops. However, projected higher temperaturesat the end of crop cycle are expected to affect not only seed nutritional quality but also seed germination and storage ability.In this study, experiments were conducted on wheat (Triticum aestivum L.) and pea (Pisum sativum L.) in controlledconditions to assess the effects of high maximum daytime temperatures, between 258C and 358C, on mother plants duringgrain filling or only during grain desiccation. Grain composition and seed characteristics related to germination and seedstorage were investigated. When the stress occurred during grain filling, seed dry weight decreased, and protein and totalfatty acid concentrations increased. Higher contents of vicilins in pea and polyunsaturated fatty acids in both cropswere observed. Total starch content decreased in wheat. Sucrose : oligosaccharides ratio decreased, seed conductivityincreased and germination was altered in both crops whenever the stress occurred. All of these modifications weremainly detrimental to the seed nutritional and end-use values. Further investigations should be carried out to assessgenetic diversity, to characterise other species, and to introduce the impact of high temperatures on these seed characteristicsinto crop models