Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/9/2018
Publication Date: 11/1/2018
Publication URL: http://handle.nal.usda.gov/10113/6145395
Citation: Walia, M.K., Wells, M.S., Cubins, J., Wyse, D., Gardner, R.D., Forcella, F., Gesch, R.W. 2018. Winter camelina seed yield and quality responses to harvest time. Industrial Crops and Products. 124(15):765-775. https://doi.org/10.1016/j.indcrop.2018.08.025.
DOI: https://doi.org/10.1016/j.indcrop.2018.08.025

Interpretive Summary: Winter camelina is a new winter annual oilseed crop that has gained popularity in recent years as a crop that can be used for food and industrial uses, while providing critical environmental benefits. Our research has shown that winter camelina can be double- or relay cropped with traditional summer food crops like soybean in the Upper Midwest, which is entirely new for this region. However, little is known about the best time to harvest winter camelina to maximize its seed yield and quality. Even less is known about the development of its seed storage oil as seeds mature under the field conditions. Therefore, we ran a field experiment at two locations to determine the best harvest time to maximize seed yield and quality. Plant growth, yield, and seed quality were evaluated over eight harvest dates ranging from early June through early July. Seed yield and oil content maximized around mid-June and did not change much later. Camelina seeds accumulated oil that was rich in the heart-healthy polyunsaturated fatty acids linoleic and alpha-linolenic, which represented about 55-60% of the total fatty acids making up its oil. Also, we showed that maximum seed and oil production of winter camelina occurred when seeds were fully mature but their moisture content was too high to mechanically harvest (around 41%). An additional one to two weeks were required for the seeds to dry on plants in the field before they could be harvested. However, our results show that one could apply a desiccant to the plants or swath them when their seeds are at 41% moisture. This method could speed up the drying process and allow earlier harvesting by a week or more than normal, without losing yield. This could allow the earlier planting of a second crop in a double-cropping system. As a result, this could improve the overall production economics in in the Upper Midwest. This information will help farmers interested in growing winter camelina and benefit extension specialists and consultants advising farmers growing camelina. The information on seed oil development will benefit both the specialty seed industry and scientists researching camelina.

Technical Abstract: Winter camelina [Camelina sativa (L.) Crantz] is a winter-annual oilseed crop that allows 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 optimum harvest times to maximize winter camelina yield, and seed quality. Therefore, a study was conducted in 2016-2017 at two locations Morris, and Rosemount, Minnesota, to determine the development of 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 about mid-June corresponding to 1200-1300 cumulative growing degree days (CGDD), which associated closely with maximum seed dry weight, carbon, and protein content. Seed oil content of linoleic, oleic, and palmitic acids declined; while that of linolenic, and eicosenoic acids increased with harvest date, reaching stable levels by physiological maturity. At maximum seed mass (i.e., physiological maturity), moisture content was estimated to be 41%, which could be used as an indicator of when to swath or desiccate to hasten harvest. Results indicate that seed yield, and oil content of winter camelina maximized by mid-June, i.e. even before the crop reached physiological maturity in Minnesota. However, an additional 150-250 CGDD were required to dry seed enough for ease of harvesting.