The effect of water and nitrogen availability during grain filling on the timing of dormancy release in malting barley crops

Abstract

Pre-harvest sprouting (PHS) causes immediate loss of seed viability, making barley (Hordeum vulgare L.) grains worthless for malting purposes. Grain dormancy release rate in barley crops is genetically and environmentally controlled. A 2 year experiment was conducted to evaluate the effect of soil nitrogen and water availability during grain filling on the dormancy release pattern (and then on the PHS susceptibility) for five malting barley commercial cultivars. Drought and well-irrigated control treatments were imposed from anthesis onwards, and contrast nitrogen fertilization treatments were applied at tillering. Nitrogen availability showed no effects on dormancy release. Drought during grain filling accelerated dormancy release with respect to well-irrigated control in 2004, but not in 2005 year. Mean temperatures during the last stages of grain filling were much higher (ca. 6°C) in 2005 than in 2004, indicating that high-dormancy loss promoting temperatures had masked drought effects on dormancy release.