Effects of Volunteer Wheat and Barley on the Growth and Yield of Flax

Field experiments were conducted in 1982 and 1983 to determine the effects of increasing densities (0–70 plants m −2 ) of volunteer wheat (Triticum aestivum L. Neepawa) and barley (Hordeum vulgare L. Bonanza) on the growth and seed yield of flax (Linum usitatissimum L. Dufferin). Rectangular hyperbolic models were fitted to data using nonlinear regression analysis. Results indicated that both volunteer cereals severely reduced flax biomass and yield, with volunteer barley interference causing greater losses than volunteer wheat at equivalent densities. From the regression equations it was calculated that an intermediate density of 30 volunteer wheat plants m −2 reduced the yield of flax by 49% in 1982 and 53% in 1983, whereas an equivalent density of volunteer barley plants reduced flax yields by 56% in 1982 and 67% in 1983.