Pennycress ( Thlaspi arvense L.) Seed Persistence in the Field After Two Years

Field pennycress ( Thlaspi arvense L.), is a new oilseed winter annual crop being investigated as a source of biofuel in the United States. The purpose of this study is to assess long term survivability and dormancy of both wild-type pennycress and gene-edited golden pennycress seed. Seeds from one wild type and three gene-edited golden types that carried an edit to TT8 gene were buried at 2 cm and 15 cm depths under well-drained and poorly-drained field conditions. The seeds were exhumed at 2, 4, 6, 12, 18, and 24 months after burial and germinated to determine the viability of the seed over time. All golden seeded gene-edited lines decreased to 0% germination by 6 months while the wild black seeded variety ‘ARV1’ retained almost 60% germination after 2 years. A significant difference was seen in the ‘ARV1’ survival in the well- drained field but not in the poorly-drained field. However, there was no significant difference in seed viability for burial depth in the well-drained field but there was significant difference for burial depth in the poorly-drained field. These results indicate that gold seeded varieties carrying the edit to TT8 through gene-editing have dramatically decreased the survivability of the seed in the seedbank. Reduced survivability will greatly assist in the adoption of golden pennycress as a new viable off-season crop in the Midwest without concerns of adding to the seedbank or serving as weed pressure in primary crops.