Seed treatment affected establishment and yield in two pennycress lines

Authors: KOIRALA, NASIB - The Ohio State University; BARKER, DAVID - The Ohio State University; Gesch, Russell - Russ; Mohammed, Yesuf; HELLER, NICHOLAS - Illinois State University; HARD, ALEX - University Of Minnesota; WELLS, SAMANTHA - University Of Minnesota; PHIPPEN, WINTHROP - Western Illinois University; TAS, PAMELA - University Of Wisconsin; LINDSEY, ALEXANDER - The Ohio State University

Submitted to: Frontiers in Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/18/2023
Publication Date: 10/12/2023
Citation: Koirala, N., Barker, D., Gesch, R.W., Mohammed, Y.A., Heller, N., Hard, A., Wells, S.S., Phippen, W.B., Tas, P., Lindsey, A. 2023. Seed treatment affected establishment and yield in two pennycress lines. Frontiers in Agronomy. 5. Article 1205259. https://doi.org/10.3389/fagro.2023.1205259.
DOI: https://doi.org/10.3389/fagro.2023.1205259

Interpretive Summary: Pennycress is an emerging biofuel crop that can be rotated with corn and soybean. Good fall establishment of pennycress by broadcast planting will help farmers to adopt this new crop. However, broadcasting seed can be challenging due to variable seed germination and poor seed-to-soil contact. Seed coatings that improve water absorption, germination consistency, and that inhibit fungal growth may improve pennycress establishment when broadcasting seeds. A study was conducted across nine different field sites in four US states to test the effects of five seed coating treatments on seedling emergence, soil coverage by plants in fall and spring, and seed yield at maturity of two different pennycress lines (a black-seeded and yellow-seed line). The seed coating treatments consisted of various combinations of a fungicide, growth regulator (gibberellic acid; GA), and commercially available pelleting material. Neither pennycress line benefited from pelleting without GA treatment. The black-seeded line had better establishment and yield when planted seeds were treated with GA or coated with GA plus pelleting material than seeds that were untreated. However, the yellow-seeded line did not benefit from any of the coating treatments, and in some instances, yield was reduced as much as 20 to 40% by coating treatments compared with untreated seed. Results will benefit industry partners commercializing pennycress production, farmers interested in growing pennycress, and university extension specialists, agricultural consultants, and other scientists working to improve agricultural management of pennycress.

Technical Abstract: Oilseed pennycress (Thlaspi arvense L.) is an emerging biofuel crop for use in the aviation industry that has potential as a rotational crop in corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] cropping sequences. Ensuring autumn emergence of pennycress after early broadcast seeding may help increase grower adoption. However, broadcasting seeds may result in uneven spatial distribution due to small seed size and variable germination, soil contact and moisture availability. The objective of this research was to evaluate the impact of five seed treatments and enhancements on autumn establishment in two pennycress lines (MN106NS, tt8-t/ARV1) in broadcast seeding compared with no treatment. Tested treatments were i) gibberellic acid (GA) soak, ii) fludioxonil fungicide, iii) pelleting with diatomaceous earth and a commercial binder, iv) fungicide plus pelleting, or v) fungicide plus pelleting with GA added to the binder. Seeds were planted at nine sites in four U.S. states to assess establishment (stand counts and percentage canopy cover) in the autumn and spring and seed yield after maturity. Pelleting treatments without GA were not beneficial for stand establishment of either line. The MN106NS line had greater plants m-2 and percent green cover with treatments that included GA compared to the control. Line tt8-t/ARV1 had reduced stands when pelleted compared to the untreated, and establishment was unchanged when treated with GA compared to the untreated. Seed yield for MN106NS was 20% greater than the untreated when treated with GA or pelleted. Seed yield for tt8-t/ARV1 did not increase over the untreated with any treatment and was reduced by 20-40% when pelleted. Plant establishment and yield were negatively correlated with total precipitation post-planting suggesting excessive rainfall post-planting (>60mm) may impede establishment when broadcast seeded.