IS IT FAIR TO COMPARE? ISSUES REGARDING THE TESTING OF GLYPHOSATE-TOLERANT SOYBEANS IN UNIVERSITY VARIETY PERFORMANCE TRIALS

ABSTRACT

With the introduction of herbicide-tolerant crop varieties, there is concern that university variety performance trials conducted under conventional herbicide programs may be biased in terms of yield potential. Experiments on dryland and irrigated glyphosate-tolerant soybean (Glycine max) varieties conducted at two Arkansas locations in 1998 and 2000 provide evidence there are no differences in plant height or yield potential across herbicide regimes if effective weed control is established. The research compared conventional herbicide programs to various glyphosate products. While the evidence suggests that university trials are an appropriate means of determining the yield potential of glyphosate-tolerant varieties, producers are still advised to evaluate whether effective weed control will be better attained with a glyphosate or conventional herbicide program.

ACKNOWLEDGMENTS

The authors are appreciative of the assistance from Jennifer Lafferty and Monty Malone, University of Arkansas, Cooperative Extension Service, Little Rock, AR.