Effect of sowing rate on yields and grain quality of new cultivars of spring barley

Microplot experiments with spring barley were carried out on an experimental fi eld IUNG-PIB in Pulawy. They involved 3 sowing rates: 250, 350 and 450 seed m -2 . In 2004- 2005 the cultivars Nadek, Sebastian, Widawa and Kirsty were investigated, and in 2006-2007: Toucan, Mauritia, Nagradowicki and Tocada. The experiments were conducted on good wheat complex soils (heavy loamy sand on light loam). All cultivars of spring barley responded with yield increase to the increase of sowing rate from 250 to 450 seed m -2 . Widawa, Mauritia, Nagra- dowicki and Tocada showed a higher yield increase in response to high sowing rate compared to medium rate of 350 grains m -2 . The increase of grain yield showed by all cultivars at high sowing rate was the result of an increase in the number of ears per unit area (to the highest degree in the cultivar Mauritia). Grain weight per ear (averaged across cultivars) was signifi cantly higher at low sowing rate. The increase in the protein content in grain at high sowing rate was recorded for the cultivars Widawa, Kirsty, Nagradowicki and Tocada. Signifi cantly positive effect of high sowing rate on grain plumpness was found in: Nadek, Sebastian, Toucan and Mauritia cultivars.