It's almost become a non-issue unless you know that a specific problem like Race 2 Aphanomyces will limit establishment and plant survival. Variety performance data is very limited for forage quality and only somewhat better for stand persistence. The data is generally reliable, but starting with one of these criteria will severely limit the variety selection pool. Not necessarily the best at every location, but consistently in the top one-third of varieties tested at a given location. This has been proven over and over again by using historical yield data.
Locations are really environments.
Although locations don't change from year to year, environments at the same location always undergo annual changes. If you make selections based on one location and one year, chances are heavily weighed that you won't be making the best selection. Let's look at the performance of a variety named 'Pointer' in the 2000 UW alfalfa variety performance trials. This variety was seeded at three different locations in 1999. Its performance information is presented in Table 1.