Genetic Gain and Non-Genetic Loss of Oat Yield in Quebec Oat Variety Trials

New crop cultivars are introduced into production every year, but yield gains in growers’ fields may not materialize due to non-genetic factors such as declining soil fertility or climate change. This study aimed to estimate the genetic gain from new oat cultivar introductions and yield trend in Quebec, using data from the provincial oat variety trials conducted between 2010 and 2024. The estimated genetic gain in both oat sub mega-environments (ME2a: south; ME2b: north) was approximately 39 kg/ha per year. However, this was insufficient to offset the estimated non-genetic losses of 124 kg/ha per year in ME2a and 108 kg/ha per year in ME2b, resulting in a net yield decline over time. The trend of non-genetic loss was accompanied by increased mean temperature at 0.05 °C per year and in total rainfall at 0.9 mm per year in May and June. The possibility of declining soil fertility as a driver of the non-genetic loss was discussed.