Growth environment but not seed position on the parent plant affect seed germination of two Thlaspi arvense L. populations

• Differences in apical and basal seed germination of Thlaspi arvense were determined.
• Physicochemical attributes of seed were not related to germination differences.
• Growth environment rather than seed physicochemical attributes affected germination

Thlaspi arvense L. is a common weed found in most temperate regions throughout the world that also shows excellent potential for domestication as an oilseed crop. The complexity of T. arvense seed dormancy presently makes it difficult to predict its emergence and manage it as an oilseed crop. Therefore, a better understanding of factors controlling seed dormancy will help develop strategies for managing its weediness and facilitate development of crop genotypes. T. arvense has semi-indeterminate growth and seeds developed at the base of the inflorescence (basal) generally mature sooner than those near the top (apical). However, little is known about the maternal influences on the level of dormancy and germination of basal and apical seeds. To study this, two T. arvense populations, one from Spain and another from USA, were both grown at field sites in Almenar, Spain and Morris, Minnesota, USA during the same growing season (autumn 2012-summer of 2013). Basal and apical seeds collected at maturity were analyzed for mass, total protein and carbon content, oil content, and fatty acid profiles. Under controlled environment conditions, seed germination was measured at 5, 8, 11, 14, 17, and 20 °C and germination rate estimated at 8 °C. Seed position on the inflorescence did not affect germination consistently nor were there clear differences in seed attributes between positions. However, seeds of both populations produced at Almenar had lower germination and were consistently larger and contained higher oil and carbon content than seeds produced at Morris. Results indicate that environmental influences at each growth location played a larger role in influencing dormancy and germination of seeds produced than did the seed attributes measured or position of seeds on the inflorescence.