Impacts of drought and elevated temperature on the seeds of malting barley

High seed quality is key to agricultural production, which is increasingly affected by climate change. We studied the effects of drought and elevated temperature during seed production on key seed quality traits of two genotypes of malting barley (Hordeum sativum L.). Plants of a Hana-type landrace (B1) were taller, flowered earlier and produced heavier, larger and more vigorous seeds that resisted ageing longer compared to a semi-dwarf breeding line (B2). Accordingly, a NAC domain-containing transcription factor (TF) associated with rapid response to environmental stimuli, and the TF ABI5, a key regulator of seed dormancy and vigour, were more abundant in B1 seeds. Drought significantly reduced seed yield in both genotypes, and elevated temperature reduced seed size. Genotype B2 showed partial thermodormancy that was alleviated by drought and elevated temperature. Metabolite profiling revealed clear differences between the embryos of B1 and B2. Drought, but not elevated temperature, affected the metabolism of amino acids, organic acids, osmolytes and nitrogen assimilation, in the seeds of both genotypes. Our study may support future breeding efforts to produce new lodging and drought resistant malting barleys without trade-offs that can occur in semi-dwarf varieties such as lower stress resistance and higher dormancy.

Automated summary

Seed quality is crucial for agricultural production, but it is affected by climate change. This study investigated the influence of drought and elevated temperature on key seed quality traits in two genotypes of barley. The results showed that different genotypes of barley had varying responses to drought and temperature stress, with differences in seed size, weight, and vigor. Transcription factors associated with environmental responses and seed dormancy were found to be more abundant in one genotype. Drought significantly reduced seed yield in both genotypes, while elevated temperature only affected seed size. Metabolite profiling revealed differences in metabolic processes between the embryos of the two genotypes, with drought affecting amino acid metabolism in both genotypes. This study could support future breeding efforts to develop lodging and drought-resistant barley varieties without compromising stress resistance and dormancy.