Strategy for Selecting the Best Performing Varieties

NDSU Extension Service, ND Agricultural Experiment Station, NDSU College of Agriculture
http://www.ag.ndsu.nodak.edu/

What is the best strategy for selecting a new, or the best, variety? A simple enough question, but one in which too little attention is given, in my opinion. There are a few basic principles that should be remembered.

First, pest resistance, marketing factors (test weight and protein) yield and other agronomic characteristics should not be dealt with in the same manner. Let's use pest resistance for example. We want a variety in many growing areas with good resistance to scab. So let's say we find a variety trial table from one year near our farm that lists yield, test weight, protein and includes a scab rating. A tendency might be to view this information as though it is sufficient to select the variety that best meets our needs. Not necessarily, however.

Keep in mind that this was a variety trial; someone noted that scab was present and rated the trial. A close examination may reveal that few varieties in the table rated poorly under FHB pressure. Since none of the varieties were rated as poor, they apparently must perform well under FHB, right? Well, the fact is that the disease level in this particular plot trial may have been insufficient to differentiate among varieties. Thus, it is important to look and compare elsewhere for a rating among varieties. This information can be found in the variety description tables found in each of the small grain variety selection guides.

Varieties should meet minimum requirements

When looking at the variety description tables you will note that several newer varieties are not rated for some disease. This is because there is too little information was available to rate them. This lack of information should be viewed as a precautionary statement.

This same type of scenario can be described for lodging and other traits that are influenced by various plant stresses. In each variety description table are relative ratings for each variety. Judiciously using this information to eliminate varieties that do not meet minimum requirements should be the first step in selecting a variety.

Ratings for specific varieties are changed periodically. This is most frequent for leaf rust resistance. Prevalent races of leaf rust are continually changing, and when a new race appears that is virulent on a variety previously listed as resistant, the rating is changed.

Moisture, temperature, solar radiation, pest pressure and soil conditions to name a few are never the same from year to year, even at the same location. A variety that performs very well at a single location in one year may look appealing. Before choosing such a variety, look at its performance at other locations. If it performs well at other locations, it is likely a good choice, but if it is poor at other locations then its performance is suspect. Variety trials summarized over multiple locations and years provide the most reliable way to differentiate among varieties. The top performing variety from this type of summary is the most adapted. On average, it has performed better under a range of environmental conditions. Single year, single-location data provides the least reliable comparisons among varieties.

Each year there were new varieties of wheat, durum and barley released that may look promising. Again, review the performance data properly on these new varieties before growing them. Frequently I get a call from an individual looking for information about a particular variety that I have not heard of. If you can't verify the relative performance of a variety with multiple locations and years worth of data, either experiment with it on a limited acreage next year, or don't gamble on it at all.

By Dr. Michael D. Peel, former NDSU Small Grains Extension Agronomist