Harvest attributes and seed quality predict physiological maturity of pennycress

Authors: CUBINS, JULIJA - University Of Minnesota; WELLS, SAMANTHA - University Of Minnesota; WALIA, MANINDER - University Of Nevada; WYSE, DONALD - University Of Minnesota; BECKER, ROGER - University Of Minnesota; FORCELLA, FRANK - Retired ARS Employee; GARDNER, ROBERT - University Of Minnesota; JOHNSON, GREGG - University Of Minnesota; Gesch, Russell - Russ

Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/28/2021
Publication Date: 2/1/2022
Citation: Cubins, J.A., Wells, S.S., Walia, M.K., Wyse, D.L., Becker, R., Forcella, F., Gardner, R.D., Johnson, G.A., Gesch, R.W. 2022. Harvest attributes and seed quality predict physiological maturity of pennycress. Industrial Crops and Products. 176. Article 114355. https://doi.org/10.1016/j.indcrop.2021.114355.
DOI: https://doi.org/10.1016/j.indcrop.2021.114355

Interpretive Summary: Pennycress is a new oilseed crop related to canola being developed as a feedstock for biofuels and bioproducts. Pennycress can be grown as a winter annual crop between corn and soybean production, and thus, can help diversify cropping systems in the upper Midwest Corn Belt region. Semi-domesticated pennycress still shows the ability to shatter seed (i.e., shed seed at maturity). Therefore, information is needed to make better decisions of when to harvest pennycress to maximize its seed and oil yield. A multi-year multi-location field study was conducted to determine when physiological maturity (maximum dry matter accumulation in seed) for pennycress occurs, the optimum time for harvesting to maximize yield, and the development of seed oil quality as plants mature. Maximum seed dry matter accumulation occurred within the timeframe of maximum seed yield, but maximum oil content occurred later. However, if harvested during the optimum time for yield, there was very little oil loss. The best time to harvest pennycress to maximize yield occurred when seed moisture was still quite high (about = 40%). But, delaying pennycress harvest to when seed moisture was low enough for mechanical harvest, resulted in a 26% loss of seed yield (due to shattering). Developing pennycress varieties with improved seed retention will be an important breeding goal to overcome this problem. In the meantime, using management practices like desiccation and swathing prior to harvest may be necessary. Results will benefit crop breeders who are working on improving pennycress and researchers developing improved harvest management practices. Furthermore, results will benefit the specialty crop industry and other researchers interested in the development of oil quality with crop maturation.

Technical Abstract: In the Upper Midwest, corn (Zea mays L.) and soybean (Glycine max [L.] Merr.) dominate the landscape, but only for six to seven months of the year. Thus, opportunities exist to establish crops that can utilize the remainder of the growing season and contribute to overall farm profitability. One species of interest is pennycress (Thlaspi arvense L.), but a lack of established agronomic best management practices is a barrier to successful crop production. The objectives of this study were to identify a range of cumulative growing degree days (CGDD) corresponding to pennycress physiological maturity, determine the optimal harvest window that maximizes pennycress seed yield and oil content, and characterize changes in pennycress seed attributes over seed maturation. This study was conducted over the 2016-2017 and 2017-2018 growing seasons with "MN106" pennycress at two locations in Minnesota, USA. Seed dry weight stabilized within the window of maximum seed yield, but oil content did not maximize until after this period. However, there was minimal loss of oil content when pennycress was harvested within the seed yield maximization window. Based on these parameters, as well as seed moisture, it was estimated that pennycress reached physiological maturity between 2230 and 2250'C d CGDD, or about a week prior to harvest maturity in terms of crop phenology. Delaying harvest to harvest maturity resulted in a 26% loss in harvestable seed due to seed shatter compared to the average maximum seed yield of 928 kg ha-1. Ensuring maximum pennycress seed yield and oil content at harvest is imperative to successful production and contribution to farm economic viability.