摘要：Recent theoretical work suggests that government policies may in°uence the quality mix of a commodity. This paper provides empirical evidence of quality responses to government policies for wheat policy implemented in France. Analysis is conducted using a detailed data set that includes the class, a measure of varietal importance (area of land used for seed multiplication), quality measures, and experimental yields for each wheat variety grown in France between 1973 and 1999. Results show statistically signi¯cant changes in the distribution of wheat produced across quality classes, and in quality and yield indexes, occurring at times of important policy changes.
