Principles of selecting small grain varieties

The first important consideration when selecting a variety is the mix and match principle. This is because varieties don’t perform the same one year to the next.

You need yield replication trials to get a better estimate of the variety’s true yield potential in a given region. Between and within locations, there are differences. This variation is due to the environment and the variety by environment interaction.

Because yield trial results are for previous years, they’re only an indicator of how a variety may perform in subsequent years. Different weather and/or the occurrence of a disease can change a variety’s performance, and its ranking relative to other varieties.

The best defense is to mix and match a number of varieties rather than using a single variety in all your farm’s fields. This hedging approach is like spreading your financial risk by investing in a mutual fund rather than a single stock. By selecting two or three varieties instead of one, you hedge against potentially negative environmental interactions if one variety falters.

Wheat (spring and winter), barley and oats are cool-season annuals. This means the plants grow optimally in temperatures between 32 and 85 degrees Fahrenheit.

Above 85, photosynthesis—the process that converts light energy into chemical energy—starts to diminish to the point that it takes more energy for the plant to maintain itself than it produces. At temperatures above 90, photosynthesis actually completely shuts down as key enzymes become non-functional.

Because of this upper-temperature limit and the climatic conditions in Minnesota and parts of North Dakota, it’s important that a small grain crop grows and matures before the heat of summer cuts the season short. In the southern counties, the earlier-maturing varieties have a better chance to reach their yield potential by escaping the heat.

Further north, you can relax this standard, as chances for hot temperatures decrease. Early seeding will avoid the summer’s heat during sensitive vegetative and reproductive stages.

Drought stress can be a serious constraint in some years and regions (i.e., western North Dakota). When rotated with crops that use more moisture than the previous year’s rainfall, soil moisture levels can become depleted.

Soybeans, sunflowers, corn, and sugarbeets are examples of full-season crops that generally will use more moisture during the growing season than the annual amount they receive.

In general, earlier-maturing varieties and varieties that are of standard height (rather than of semi-dwarf stature) handle moisture stress better and reduce drought-related losses.

Straw strength and tendency to shatter

Straw strength and tendency to shatter are two important agronomic characteristics that determine whether a variety fits into your production system.

Larger acreage and a desire to straight cut the grain for harvest will favor selecting semi-dwarf varieties with good straw strength and resistance to shattering. This is because it’ll allow you to harvest the crop without worrying about losing yield to either lodging or shattering.

Winter hardiness

When selecting winter wheat varieties, it’s important to consider winter hardiness in addition to other agronomic traits, such as yield and disease resistance.

Only grow the most winter-hardy varieties in Minnesota’s northern regions or if planted into fields with little or no previous crop residue that might catch snow. The most winter-hardy varieties, generally those developed in North Dakota and Canada, have a greater chance of survival when the winter is open (little snow) or when it’s planted with little previous crop residue.

In southern North Dakota, less winter-hardy varieties have been successfully grown in fields where high residue levels are maintained at seeding time.

Diseases of economic importance

The most cost-effective method of disease and pest control is growing varieties that are genetically resistant to the particular disease or pest. View diseases of economic importance.

Varieties aren’t tested and/or selected for resistance to all potential diseases and pests. Diseases of major economic importance are:

• Leaf and stem rust.

• Septoria and tan spot.

• Fusarium Head Blight.

• Root rots.

When selecting varieties, consider the diseases that dominate your area of production and the field’s previous crop, and try to match available genetic resistance with the likelihood of a disease problem developing.

Scab epidemic

For hard red spring and durum wheat, consider all data when choosing wheat varieties. However, the scab epidemic in areas that grow hard red spring wheat has demonstrated a clear need to give greater attention to a variety’s tolerance to this devastating disease.

University evaluations of scab include:

• Disease severity, based on how the disease visually spreads on the spike.

• Grain soundness, which reflects the variety’s ability to maintain plump, sound kernels.

Consider these ratings together to reduce the risk of loss. To further reduce risk, it’s highly recommended to use more than one variety to provide different days to heading and different seeding dates.