Novel loci and a role for nitric oxide for seed dormancy and preharvest sprouting in barley

• Published in: Plant, cell and environment Vol. 42; no. 4; pp. 1318 - 1327
• Main Authors: Nagel, Manuela, Alqudah, Ahmad M., Bailly, Marlène, Rajjou, Loïc, Pistrick, Sibylle, Matzig, Gabriele, Börner, Andreas, Kranner, Ilse
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.04.2019; Wiley
• Subjects: after‐ripening; Agronomy; Arabidopsis Proteins - genetics; Arabidopsis Proteins - physiology; Barley; Breweries; Brewing; Chemical and Process Engineering; Chromosomes; Crop improvement; DOG1; Dormancy; Engineering Sciences; Flowering; Food engineering; Gene mapping; Genes, Plant - genetics; Genes, Plant - physiology; Genome-Wide Association Study; Genotypes; Germination; Germination - genetics; Germination - physiology; GWAS; Heritability; Homology; Hordeum - genetics; Hordeum - metabolism; Hordeum - physiology; Hordeum vulgare; Life Sciences; Loci; Mapping; Nitric oxide; Nitric Oxide - physiology; Plant Dormancy - genetics; Plant Dormancy - physiology; Ripening; Seeds; Vegetal Biology; germination; after-ripening; GWAS; Hordeum vulgare; DOG1; hordeum vulgare
• DOI: 10.1111/pce.13483
• ISSN: 0140-7791

Barley is used for food and feed, and brewing. Nondormant seeds are required for malting, but the lack of dormancy can lead to preharvest sprouting (PHS), which is also undesired. Here, we report several new loci that modulate barley seed dormancy and PHS. Using genome‐wide association mapping of 184 spring barley genotypes, we identified four new, highly significant associations on chromosomes 1H, 3H, and 5H previously not associated with barley seed dormancy or PHS. A total of 71 responsible genes were found mostly related to flowering time and hormone signalling. A homolog of the well‐known Arabidopsis Delay of Germination 1 (DOG1) gene was annotated on the barley chromosome 3H. Unexpectedly, DOG1 appears to play only a minor role in barley seed dormancy. However, the gibberellin oxidase gene HvGA20ox1 contributed to dormancy alleviation, and another seven important loci changed significantly during after‐ripening. Furthermore, nitric oxide release correlated negatively with dormancy and shared 27 associations. Origin and growth environment affected seed dormancy and PHS more than did agronomic traits. Days to anthesis and maturity were shorter when seeds were produced under drier conditions, seeds were less dormant, and PHS increased, with a heritability of 0.57–0.80. The results are expected to be useful for crop improvement. In barley, dormancy‐related issues affect seed quality, with downstream effects for the malting process. We identified new genetic loci responsible for dormancy and preharvest sprouting, and showed that environmental conditions during seed production alter the genetic control of dormancy.