Wheat (Triticum aestivum) yield reduction from common milkweed (Asclepias syriaca) competition

• Published in: Weed science Vol. 45; no. 1; pp. 127 - 131
• Main Authors: Yenish, J.P, Durgan, B.R, Miller, D.W, Wyse, D.L
• Format: Journal Article
• Language: English
• Published: 01.01.1997
• Subjects: additive models; area of influence; Asclepias syriaca; competitive ability; crop yield; crop-weed competition; grains; mathematical models; population density; Triticum aestivum; yield losses; Minnesota
• ISSN: 0043-1745; 1550-2759
• DOI: 10.1017/S0043174500092572

Yield loss of hard red spring wheat due to competition from common milkweed was measured in grower fields in Minnesota. Wheat yield loss was measured using the area of influence and additive competitive methods. Simple linear regression of wheat yield and percentage wheat yield loss against distance from a common milkweed shoot gave r2 values of 0.013 and 0.015, respectively, indicating limited value of the area of influence model for common milkweed in spring wheat. In an additive competition model, wheat yield was reduced 47% at the highest density of 12 common milkweed shoots m-2. Coefficients of determination for percentage yield loss regressed against common milkweed shoot density were 0.548, 0.547, and 0.529 for simple linear, nonlinear rectangular hyperbolic, and linear square root function models, respectively. Regression of percentage yield loss against common milkweed biomass resulted in r2 values of 0.566, 0.645, and 0.658 for simple linear, nonlinear rectangular hyperbolic, and linear square root function models, respectively. Restrictions of common milkweed density due to factors other than competition limited yield loss response to the simple linear phase of both the nonlinear rectangular hyperbolic and the linear square root function models previously described.