Time of wild oat (Avena fatua) panicle clipping influences seed viability
Citation
Tidemann, B.D., Harker, K.N., Johnson, E.N., Willenborg, C.J., Shirtliffe, S.J. (2020). Time of wild oat (Avena fatua) panicle clipping influences seed viability, 68(3), 260-267. http://dx.doi.org/10.1017/wsc.2020.19
Plain language summary
Wild oat is one of the most problematic weed species in western Canada due to widespread populations, resistance to herbicides, and seed dormancy. In wheat, and especially in shorter crops such as lentil, wild oat seed heads become visible over top of the crop and could potentially be cut off to prevent seed production. A two year study in wheat and lentil was conducted in Lacombe, AB and Saskatoon, SK in 2015 and 2016 to looking at clipping of wild oat seed heads to determine when wild oat seeds become viable. Clipping for each crop began when the majority of the seed heads were visible above the respective crops and continued after that at weekly intervals until seeds began to be released from the seed heads. At the start of clipping, between 0 and 10% of the wild oat seeds were viable. By the last clip, 95% of the wild oat seeds were viable. Seed moisture and awn angle weren't effective tools to estimate wild oat seed viability at clipping timings. Based on wild oat seed viability, earlier clipping of wild oat is likely to be more effective in terms of population management and easier to implement in shorter crops such as lentil. Investigations into long-term effects of clipping on wild oat populations are needed to evaluate the efficacy of this management strategy on wild oat.
Abstract
© 2020, Her Majesty the Queen in Right of Canada as represented by the Minister of Agriculture and Agri-Food. Published by Weed Science Society of America.Wild oat (Avena fatua L.) is one of the most problematic weed species in western Canada due to widespread populations, herbicide resistance, and seed dormancy. In wheat (Triticum aestivum L.), and especially in shorter crops such as lentil (Lens culinaris Medik.), A. fatua seed panicles elongate above the crop canopy, which can facilitate physical cutting of the panicles (clipping) to reduce viable seed return to the seedbank. However, the viability of A. fatua seed at the time of panicle elongation is not known. The objective of this study was to determine the viability of A. fatua seed at successive time intervals after elongation above a wheat or lentil crop canopy. A 2-yr panicle clipping and removal study in wheat and lentil was conducted in Lacombe, AB, and Saskatoon, SK, in 2015 and 2016 to determine the onset of viability in A. fatua seeds at successive clipping intervals. Manual panicle clipping of A. fatua panicles above each crop canopy began when the majority of panicles were visible above respective crop canopies and continued weekly until seed shed began. At the initiation of panicle clipping, A. fatua seed viability was between 0% and 10%. By the last clipping treatment (approximately 6 to 7 wk after elongation), 95% of the A. fatua seeds were viable. Seed moisture and awn angle were not good predictors of A. fatua viability, and therefore were unlikely to provide effective tools to estimate appropriate timing for implementation of A. fatua clipping as a management technique. Based on A. fatua seed viability, earlier clipping of A. fatua is likely to be more effective in terms of population management and easier to implement in shorter crops such as lentil. Investigations into long-term effects of clipping on A. fatua populations are needed to evaluate the efficacy of this management strategy on A. fatua.