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Changes in seed composition and germination of wheat and pea when exposed to high temperatures during grain filling and maturation
Most studies on the effects of climate change have been conducted on grain yield and composition; only few have focused on seed germination and storage ability, especially in temperate crops. However, projected higher temperatures at the end of crop cycle, are expected not only to affect seed nutritional quality but also seed germination and storage ability. In this study, experiments were conducted on wheat and pea in controlled conditions to assess the effects of high maximum day temperatures between 25°C and 35°C applied on mother plants (i) during grain filling or (ii) only during grain desiccation. Grain composition and seed characteristics related to germination and seed storage were investigated. When the stress occurred during grain filling, seed dry weight decreased, protein and total fatty acid (FA) contents increased. Higher contents of vicilins in pea and polyunsaturated FAs in both pea and wheat were observed. Total starch content decreased in wheat. The sucrose/oligosaccharides ratio and seed conductivity decreased, germination was altered in both crops whenever the stress occurred. All of these modifications were mainly detrimental to the seed nutritional and end-use values. Further investigations should be carried out to assess genetic diversity, to characterize other species and to introduce the impact of high temperatures on these seed characteristics into crop models.
CP17397 Accepted 09 January 2018
© CSIRO 2018