Scholarly Work - Land Resources & Environmental Sciences
Permanent URI for this collectionhttps://scholarworks.montana.edu/handle/1/8680
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Item Impact of growing conditions on the competitive ability of Camelina sativa (L.) Crantz (Camelina)(2013-03) Davis, Phillip B.; Maxwell, Bruce D.; Menalled, Fabian D.It has been claimed that Camelina sativa, a recently introduced crop in the northern Great Plains, is a highly competitive species. However, this issue has not been formally tested. Utilizing replacement series diagrams, we assessed the importance of growing conditions in the competitive ability of C. sativa. Results indicated that canola and Bromus tectorum were superior competitors in both loam and sandy soils, thus providing evidence that C. sativa may not be as competitive as previously indicated.Item Impact of Biotic and Abiotic Stresses on the Competitive Ability of Multiple Herbicide Resistant Wild Oat (Avena fatua)(2013-05) Lehnhoff, Erik A.; Keith, Barbara K.; Dyer, William E.; Menalled, Fabian D.Ecological theory predicts that fitness costs of herbicide resistance should lead to the reduced relative abundance of resistant populations upon the cessation of herbicide use. This greenhouse research investigated the potential fitness costs of two multiple herbicide resistant (MHR) wild oat (Avena fatua) populations, an economically important weed that affects cereal and pulse crop production in the Northern Great Plains of North America. We compared the competitive ability of two MHR and two herbicide susceptible (HS) A. fatua populations along a gradient of biotic and abiotic stresses The biotic stress was imposed by three levels of wheat (Triticum aestivum) competition (0, 4, and 8 individuals pot−1) and an abiotic stress by three nitrogen (N) fertilization rates (0, 50 and 100 kg N ha−1). Data were analyzed with linear mixed-effects models and results showed that the biomass of all A. fatua populations decreased with increasing T. aestivum competition at all N rates. Similarly, A. fatua relative growth rate (RGR) decreased with increasing T. aestivum competition at the medium and high N rates but there was no response with 0 N. There were no differences between the levels of biomass or RGR of HS and MHR populations in response to T. aestivum competition. Overall, the results indicate that MHR does not confer growth-related fitness costs in these A. fatua populations, and that their relative abundance will not be diminished with respect to HS populations in the absence of herbicide treatment.