Commercial generations of Brassica napus cause greater yield loss in Triticum aestivum, than volunteer B. napus generations

摘要

Seerey, N. J. and Shirtliffe, S. J. 2010. Commercial generations of Brassica napus cause greater yield loss in Triticum aestivum, than volunteer B. napus generations. Can. J. Plant Sci. 90: 777-783. Volunteer canola (Brassica napus L.) has become a common weed in producer fields, due to the large area cropped, and inherent harvest losses. Commonly grown B. napus varieties which segregate in subsequent generations to create volunteers with unknown competitive capabilities are developed by hybrid genetics. The objective of this study was to evaluate the effect of volunteer B. napus variety and generation on competition yield loss in hard red spring wheat (Triticum aestivum L.). Two hybrid and one open-pollinated B. napus varieties with three consecutive generations produced from each variety were grown at varying densities in a wheat stand over 5 site-years. Yield loss depended on the density of B. napus in relation to total plant density. Generational differences in B. napus seedlings resulted in differences in wheat yield losses. Brassica napus densities at maturity provided a more robust model of wheat yield loss, as there were differences in wheat yield losses due to the interaction of generation and variety of B. napus. Commercial seed generations were the most competitive plants, while volunteer generations were less competitive. The amount of yield loss caused by volunteer B. napus was highly variable. The availability of low-priced herbicides, and the competitive ability of volunteer B. napus may allow for economic thresholds concerning weed control to be surpassed at low densities of volunteer B. napus populations.