Seed pelleting and storage effects on germination of pennycress (Thlaspi arvense L.)

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

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/2/2023
Publication Date: 8/22/2023
Citation: Koirala, N., Barker, D., Gesch, R.W., Heller, N., Hard, A., Wells, S., Phippen, W., Lindsey, A. 2023. Seed pelleting and storage effects on germination of pennycress (Thlaspi arvense L.). Crop Science. 63(5):3025-3036. https://doi.org/10.1002/csc2.21077.
DOI: https://doi.org/10.1002/csc2.21077

Interpretive Summary: Pennycress is a new and emerging bioenergy oilseed crop of interest to farmers. Varieties are being developed with improved agronomic traits such as reduced seed shatter and altered seed coat characteristics. Because pennycress is a small-seeded crop, it presents challenges for field establishment. A growth chamber experiment was conducted to evaluate various seed treatments on the germination and seedling vigor of four different pennycress lines (three black-seeded and one yellow-seeded lines). Seeds were treated with and without the growth regulator gibberellic acid (GA), with or without a seed coating made from a binder solution, and GA plus seed coating. After treatment, seeds were stored for 0, 1, 3, 6, and 12 months at 73°F and 50°F before removal and testing their germination and vigor over 7 days. Compared with the untreated control, germination of the GA-treated, black-seeded lines increased across all storage durations by 5-75%. The seed coating treatment alone increased germination of black-seeded lines 4-30%, but only up to 3 months of storage. Germination of the yellow-seeded pennycress was not improved with GA treatment and was negatively affected by the coating treatment after 3 months of storage. The GA treatment generally improved seedling vigor while the coating treatment generally negatively impacted vigor at 9 and 12 months of storage. Seed treatment can benefit germination and vigor of black-seeded lines within 3 months of storage but may negatively affect performance of golden-seeded lines, or all pennycress seed-types after 9 months of storage. Results will benefit the specialty seed industry and researchers interested in improving planting and seedling establishment of pennycress.

Technical Abstract: Pennycress (Thlaspi arvense L.) is an emerging bioenergy oilseed crop of interest to farmers in the Upper Midwestern United States. Improved lines with beneficial agronomic traits are being developed, including lines with reduced silicle shattering and altered seed coat characteristics. However, fall planting and establishment are still challenging for this small-seeded crop. A controlled-environment experiment was conducted to assess the impact of seed treatment and pelleting on pennycress germination and seedling vigor of four pennycress lines (three black and one golden colored seed) following storage for 0, 1, 3, 9, and 12 months in warm or cold conditions (23 or 10°C, respectively). Seeds were either treated with a gibberellic acid (GA) soak, seed pelleting, or pelleting with GA added to the binder solution in addition to the untreated control. After each storage duration, seeds were germinated in darkness and counted daily for 7 days to obtain total germination. Vigor indices were calculated using changes in daily germination values. Compared with the untreated control, germination percentage increased for the black-seeded lines with treatments containing GA across all storage durations by 5-75%. Pelleting alone increased germination of black-seeded lines 4-30%, but only until 3 months storage. The GA treatments did not increase germination of the golden-seeded line, and germination was negatively affected by pelleting treatments after 3 months of storage. The GA soak treatment was most effective at improving seed vigor indices compared with other treatments, while pelleting negatively affected vigor scores at 9 and 12 months storage. Similar effects on germination from treatment were observed under both warm and cold storage conditions. Results indicate seed treatment can benefit germination and vigor within 3 months of storage for black-seeded lines but may negatively affect performance of golden-seeded lines, or all pennycress seed-types after 9 months of storage.