Dr. Joe Lauer, UW-Madison Agronomy and Extension State Corn Specialist
Plant breeders and agronomists test thousands of commercial and new experimental hybrids and varieties for several years at many locations over a range of plant populations, other management practices and environments. These crop performance trials determine which hybrids/varieties have yielding ability superior to current commercial hybrids/varieties and estimate disease resistance and other important characteristics.
For a copy of the 2019 crop performance trials see the following links:
Corn: http://corn.agronomy.wisc.edu/HT/2019/2019Text.aspx
Soybean: https://coolbean.info/soybean-research/variety-trial-results/
Barley, Oat, and Wheat: https://coolbean.info/small-grains/variety-trial-results/
These results are a good place to start when evaluating hybrids and varieties to grow during 2020. Certainly, an on-farm test in conjunction with seed company trials, and University trials would probably give the best information, if all hybrids/varieties of interest were in the trials. Since most farmers do not have the resources to conduct on-farm trials at several locations, using unbiased results from other trials to supplement on-farm yield results can increase the chance of picking a hybrid that will do well next year.