Barley (Hordeum vulgare L.) producers in northern, marginal agricultural areas require cultivars that are both early maturing and high yielding. However, negative relationships between these two characteristics limit their simultaneous improvement. A better understanding of the relative contribution of the developmental stages to grain yield would assist breeders' selection. This study was undertaken to assess the relationships between patterns of phenological development and grain yield in barley grown in a subarctic environment. Sixteen genetically diverse spring barley cultivars were grown for 3 yr at Palmer, Alaska, and evaluated for grain fill rate, grain fill period, growing degree days (GDD) to heading, GDD from heading to physiological maturity, and GDD from physiological maturity to ripe maturity. Cultivars developed in temperate regions tended to have slower grain fill rates than those developed in subarctic regions. Rapid grain fill rate was associated with high kernel weight, but not with grain fill duration or grain yield. Increasing GDD to heading would result in higher grain yield, while increasing grain fill duration would have little effect. These results indicate that northern-adapted cultivars should have pre-heading periods lasting as long as possible, followed by short grain-fill periods. Simultaneous selection for early maturity and relatively long time to heading is recommended for the development of early-maturing, high-yielding cultivars adapted to northern conditions. Key words: Barley, Hordeum vulgare L., phenology, development, yield
A Novel QTL for Powdery Mildew Resistance in Nordic Spring Barley (Hordeum vulgare L. ssp. vulgare) Revealed by Genome-Wide Association Study