Increasing impact of plant breeding on barley yields in central Norway from 1946 to 2008

With 4 figures and 4 tables Spring barley (Hordeum vulgare L.) is the most important cereal crop in Norway. The northernmost area of barley cultivation is located in Trøndelag, which is a geographically confined agricultural area in central Norway (63–65°N). The objectives of this study were to study the barley yields in this region over the time period 1946–2008, and to estimate the impact of genetic improvements. The analysis was based on the official yield statistics and historical data from a total of 890 variety trials conducted in the region. During the period 1946–2008, an overall yield increase of 70% could be observed in farmers’ fields, of which 48% could be attributed to the introduction of new varieties. Splitting the studied time frame into the three subperiods 1946–1960, 1960–1980 and 1980–2008, new varieties accounted for 29%, 43% and 78% of the observed yield increase, respectively. As farmers have responded to environmental levies on fertilizers and other agricultural policy measures with less intensive production practices, the continued yield increase in barley has relied heavily on plant breeding.