Discussion

            The majority of results from this study concur with previously published data about planting date affects on seed characteristics. Later planting negatively affected grain yield at four locations, percent oil at two locations and percent ALA at four locations and at one location, positively influenced percent ALA. Some cultivars responded to later planting more dramatically than others for grain yield and percent ALA. The cultivars York, Carter and Hanley produced significantly higher grain yield than Bethune and Norlin at two sites. At two sites, Bethune had the highest percent oil and Norlin had the least. Carter and Hanley yielded the highest percent ALA at three sites while Bethune yielded the least.

These results suggest that flax should be planted as early as possible in the spring planting season to obtain the highest yields and oil quality. The optimal planting date for different regions in the upper Midwest will depend on spring soil conditions and competition from other crop needs. It appears that cultivars York, Carter and Hanley will give farmers the highest grain yields in the region and that all varieties can meet the industry total oil requirement of 36%. However, although Carter and Hanley yielded the highest percent ALA, even these cultivars did not meet the industry requirement of 53 % ALA. Additional cultivars will need to be tested to provide producers with additional options.