ARS | Publication request: Thlaspi arvense (Pennycress) germination, bolting and mechanical harvest seed loss

Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: September 11, 2011
Publication Date: September 11, 2011
Citation: Isbell, T., Cermak, S.C., Evangelista, R.L. 2011. Thlaspi arvense (Pennycress) germination, bolting and mechanical harvest seed loss [abstract]. Association for the Advancement of Industrial Crops Conference. p. 5.

Technical Abstract: Pennycress is being developed as an off-season rotation crop between annual corn and soybean production. This rotation scheme may offer distinct advantages to farmers by providing additional farm income from an otherwise fallow season with little impact on the subsequent soybean production. The seed contains up to 36% oil with the major fatty acid as erucic (38.1%). The fatty acid composition in thlaspi has been shown to have physical properties suitable for biofuels like biodiesel and hydro-treated renewable jet fuel (HRJ). Like many developing new crops, many aspects of pennycress growth and development have yet to be fully characterized. Even rudimentary conditions for germination, seed storage and bolting are lacking. A standard germination protocol was established for evaluating the germination rates of thlaspi germplasm. Ideal conditions for germination were found to be a 12 hour photo period with a diurnal temperature variation of 27 deg C daylight and 11.5 deg C dark. Germination rates were determined at 14 days with initial germination of most of the seeds occurring by 7 days. Using these germination conditions, a long term seed storage study was undertaken. Freshly hand harvested seed from 2009-2010 plots of the Beecher line were placed in a number of storage conditions; sealed containers, breathable containers, near constant temperature and fully exposed to outdoor temperature fluctuations. Germination rates were determined at 1 month intervals up to 6 months then at 3 month intervals thereafter. Seeds stored in the freezer failed to germinate at any time during the study. Seeds exposed to outdoor temperature variations developed the best germination rates early in the study but the rates quickly diminished upon exposure to cold winter temperatures. Seed stored near constant room temperature developed the best germination with the highest rates observed (85%) after one year of storage. A set of experiments were conducted in the growth chamber to determine the impact of temperature and day-length on bolting within pennycress. The experiments demonstrated that changing day-length from 12 hours to 7 hours then back to 16 hours at constant temperature did not induce bolting. Conversely, under constant 12 hour day-length, all the plants bolted after exposure to temperatures near 0 deg C for 14 days followed by several weeks of temperatures at 15 deg C. One tenth acre field plots with densities ranging from 14-270K plants per acre were established and allowed to reach full maturity. Immediately prior to combine harvest, 10 weigh boats with a total area of 1.74 ft2 were placed in the field. Immediately after the combine harvested the standing crop, the weigh boats were collected and seed loss due to mechanical harvest was evaluated. Seed loss ranged from 27-97 lbs/acre with the highest densities yielding the highest loss rates. A qualitative evaluation of the plots prior to harvest indicated that more seed was dispersed on the ground than was collected in the weigh boats after mechanical harvesting, indicating that weather induced shattering could be a problem.