Winter camelina seed yield and quality responses to harvest time

Winter camelina [Camelina sativa (L.) Crantz] is an winter-annual oilseed crop that offers the potential for producing a second crop in the Upper Midwest. However, little is known about changes in oil, fatty acid (FA) composition and protein content as seeds mature in the field, nor the best harvest time to maximize winter camelina seed yield and quality. Therefore, a study was conducted in 2016–2017 at two locations Morris and Rosemount, Minnesota, to determine the changes in seed yield and quality from the beginning of seed-set to full maturity in winter camelina. Plant growth, seed yield and seed quality traits were evaluated over eight harvest dates ranging from early June through early July. Seed yield and oil content at both locations did not change significantly after mid-June corresponding to 1200–1300 °C d cumulative growing degree days, which resemble closely with maximum seed carbon and protein content. As the harvest date progresses, contents of seed linoleic, oleic and palmitic acids declined, while that of linolenic and eicosenoic acids increased, reaching their stable levels by physiological maturity. At maximum seed mass (i.e., physiological maturity), moisture content was estimated to be 410 g kg⁻¹, which could be used as an indicator of when to swath or desiccate to hasten harvest. Results indicated that seed yield and oil content of winter camelina maximized by mid-June, before the crop reached physiological maturity in Minnesota. However, an additional 150–250 °C d was required to dry seed enough for ease of harvesting.