Factors to consider when selecting a wheat variety
In recent years, wheat producers are faced with a blessing, which some may also consider a curse: too many varieties from which to choose. One of the reasons behind having so many available varieties is that many public institutions and private companies are in the business of wheat breeding in the Plains: Colorado State University, Kansas State University, Oklahoma State University, Texas A&M University, University of Nebraska, AgriPro/Syngenta, Limagrain, and WestBred/Monsanto.
Figure 1. Producers have many wheat varieties to evaluate at 2016 wheat tours in Kansas. Photo by Romulo Lollato, K-State Research and Extension.
As a result, several new varieties are released each year. And this is a reality that not only has come to stay but will intensify in the near future. With the double haploid technology being used by many breeding programs now, varieties will tend to be released at a faster pace. This technology can reduce the time needed to release a wheat variety from 10-12 years to as few as 6 years from the time of the first cross. We are just now starting to see the first commercially available varieties resulting from the use of double haploid technology.
Having so many varieties to choose from is a blessing, and the advantages are countless. Producers can use different tools and publications to study each variety’s strengths and weaknesses, selecting varieties that best match their needs. Some of these tools are listed later in this article.
Having many varieties to choose from also gives producers the luxury of being able to avoid planting a given variety because of very specific concerns that may have arisen in certain locations in previous years. One example is the unusual temperature drop in November 2014, when temperatures fell from 80’s °F to 10’s °F overnight, and remained very cold for the following few days. That was an odd event that did not give varieties the chance to acclimate to cold conditions and become winter-hardy. Still, while some varieties showed leaf burn and normal levels of winter injury, others did not survive the event and entire fields were almost wiped out. Producers can choose not to plant those varieties for that one specific reason, and still have several excellent options to choose from.
The downside of having so many varieties are few, but some may argue that they exist. The curse of the rapid pace of variety release resulting from double haploid technology is that a newly released variety is evaluated over fewer growing seasons before it is released. As a result, some weakness that may only be expressed in one given growing season, and which would otherwise preclude the release of that variety, may be missed.
One example was a K-State line slated to be released many years ago as a variety named Sumner. This line was not released because of its stem rust susceptibility, which showed up on its very last growing season before its release as a variety. If that line had not been tested in that specific growing season, it would have been released before that weaknesses was known and it could have been a disaster.
A fast variety release process gives researchers and Extension specialists less time to understand a variety’s agronomic characteristics prior to its release. From the producer’s perspective, it takes longer to walk through all the available options and weigh the possibilities. Producers are generally busy and may not have the time to understand each variety and make a good, informed selections. Having too many options also makes selecting one or a few varieties more complicated, for the simple fact that no variety is perfect and all have different strengths and weaknesses.
Overall, the “curses” of having such a large number of available varieties are very few, but it does mean that it might take longer to select a variety nowadays than it did in the past.
Making a better decision: steps to select a wheat variety
The following information provides a step-by-step guideline, as well as relevant resources, to help producers make a better decision when selecting one or a few varieties to plant in their operation.
- Select several varieties that are adapted to your region of the state.
Regardless whether you intend to plant one variety or several on your farm, it is important to start out with a list of several good candidate varieties. The final product of interest is grain yield and therefore, it is crucial to select varieties that have shown consistent performance in the region. Varieties that worked well for you and your neighbors in the past should be considered, but also make sure and check yield results from nearby K-State variety performance tests and demonstration plots. When looking at these results is very important that results from more than a single year, and possibly more than a single nearby location, are taken into consideration.
A few great resources to consult are:
- K-State variety performance test: Start searching by year, narrow down your search by region and finally by site. Choose the site(s) nearest to you and look for varieties that are consistently toward the top. Repeat the procedure for different years to check the consistency of the variety performance. Click the link above to access the K-State variety performance test results.
- OSU variety performance tests: If you are in southern Kansas or in Oklahoma, this is also an excellent resource. Click “Variety Testing” in the link above and then “Grain Yield” to have access to similar information to the one offered by K-State, but for variety performance tests from Oklahoma. Follow the steps described above. Click the link above to access the OSU variety performance test results.
- Colorado Wheat Variety Database: This database encompasses replicated trial results from Colorado, Kansas, Oklahoma, and several other public state trials, so producers throughout the Plains can benefit. It is an excellent, easy-to-use resource that allows you to dig into data from single location, multiple locations, multiple years, and also allows for head-to-head variety comparisons. We suggest to start looking at “Single Location Trial Data”, selecting the location nearest to you, and repeating this step for several years of data for that location. Check for varieties that tend to be consistently toward the top. Afterwards, look at “Multiple Location Trial Data,” which will allow you to look at yields spanning a wider geographical region instead of a single location for one, two, three, or four years combined. Depending on region and number of years selected, you might be looking at more than 15 replicated trials combined. Thus, if a given variety remains a top yielding variety across all these replicated trials, it is a pretty good argument that you should at least look at that variety’s characteristics and consider it in your farming operation. Click the link above to access the Colorado database.
- Narrow down the number of varieties in your list to a few solid candidates.
After selecting several varieties that have shown good adaptability and stability in your region, the list needs to be narrowed down to the number of varieties you intend to plant. Ideally, at least two or three varieties (or a blend of two or more varieties) should be planted to spread the risk on your acres. Select varieties that are adapted and resistant/tolerant to the major concerns in your operation, but that have contrasting characteristics such as different maturities or disease resistance characteristics. This will help buffer the risk of a single event compromising production of the whole operation. Some factors to consider include:
- Production system: For producers who graze their wheat before taking it for grain (dual-purpose producers), selecting a variety with good forage yield: medium to late first hollow stem: Hessian fly, barley yellow dwarf, and wheat streak mosaic resistance; and good recovery from grazing is very important. Another consideration is whether the crop will be irrigated or dryland. Wheat varieties differ in their straw strength. There are a few varieties that should be restricted to dryland use, due to their high lodging potential. A history of feral rye in the field would dictate the need for a Clearfield variety and this also plays an important role in variety selection. Double-cropping wheat following soybeans may require varieties with excellent tillering potential and possibly early- to medium-early maturity to compensate for the delayed development due to late planting. No-till producers in western Kansas might be looking for tall varieties with good straw production potential to help improve water retention in the soil, so this could also play a role in selecting a variety.
- Tolerance to abiotic factors: Depending on the region of the state where your farm is located, it will be subjected to different abiotic stresses. Acid soils are a major concern in south central, central, and north central Kansas, and varieties that have good low soil pH tolerance are warranted. Meanwhile, drought is a dominant factor in western Kansas, and varieties with better drought tolerance should be favored there. Varieties differ in their tolerance to abiotic stresses, and selecting a variety with better tolerance to the major limiting factor in your operation will allow the variety’s potential to be more easily achieved.
- Disease resistance: Producers who are willing to spray a foliar fungicide have more variety options to choose from than those who are not. Some varieties have many very good characteristics and yield potential, but may have lost their resistance to some major fungal diseases and thus require a fungicide. For example, Everest has many good characteristics, such as intermediate head scab resistance, some of the best barley yellow dwarf resistance available, and acid soil and Hessian fly tolerance; however, it is very susceptible to stripe rust. If a producer is willing to spray a foliar fungicide, Everest is still an excellent option. This is also true for varieties such as Byrd, TAM 111, TAM 112, Avery, etc. Diseases such as leaf or stripe rust can be controlled with a foliar fungicide and producers have the option to budget for it in their operation. Meanwhile, other diseases require more of a systems management approach and cannot be controlled after they are established. These include virus diseases such as wheat streak mosaic and barley yellow dwarf, and can also include a fungal disease such as Fusarium head blight, which is not always successfully controlled with fungicide spraying. If these diseases are common concerns in your region, evaluate each variety’s ratings against these constraints and selecting the ones that provide better levels of resistance.
- Maturity: Selecting several varieties with differing maturities is a great tool to spread risk as well as to optimize harvest timing. You don’t want to have too many acres ready for harvest at once and then have to wait for harvest for lack of combine capacity. Early-maturing varieties will most likely have a yield advantage over later-maturing varieties in years such as 2012 when the grain filling period turns hot and dry. Also, from a historical perspective, early-maturing varieties have been more successful in the southern portion of the state, especially south central Kansas, due to the typical hot weather pattern toward the end of the growing season. On the other hand, medium-late maturing varieties will benefit from growing seasons with an extended grain filling period, such as 2015 and 2016. It is important to keep in mind that recent years favored later-maturing varieties throughout the state. If we only look at the most recent years it will be tempting to plant later-maturing varieties, even in south central Kansas. However, nothing guarantees that the next growing season will be similar. At planting time, we don’t know how the weather will turn out during grain fill. Therefore, spreading the risk in your operation by selecting varieties with differing maturities is always a good idea. In other words, you can plant a medium or medium-late maturing variety in south central Kansas, but keep it to a fraction of your acres.
A few great resources to help you walk through each variety’s characteristics as far as maturity, disease ratings, drought and soil pH tolerance, date of first hollow stem, and other agronomic characteristics are:
- K-State Wheat variety Disease and Insect Ratings 2016: This comprehensive guide to wheat varieties will allow you to compare different varieties in their agronomic and disease resistance characteristics in detail. Many varieties are individually described, others are shown in a table format which allows for easy and fast comparison. It is available online on the link above or in your county Extension office in Kansas.
- Wheat Varieties for Kansas and the Great Plains by Layton Ehmke: This private-sector book is also an excellent, comprehensive source of information regarding different varieties and their characteristics. It provides detailed ranking of varieties by traits of interest, making it easy to use. It also has a good summary of several variety performance tests in the Great Plains. While not available online, producers can purchase it in the link above if interested.
- K-State Wheat Variety Date of First Hollow Stem, Fall Forage Yield, and Grain Yield 2016: This new K-State publication compare several varieties in their fall forage production, date of first hollow stem, and grain yield under dual-purpose versus grain-only management in south central Kansas. It is a good resource for producers who graze their wheat before taking it for yield. It is available online at the link above or in your county Extension office in Kansas.
- OSU Fall forage production and date of first hollow stem in winter wheat varieties during the 2015-2016 crop year: similarly to the publication above, this OSU publication compares varieties’ forage yield and date of first hollow stem for north central and central Oklahoma. Available online at the link above or in your county Extension office in Oklahoma.
Romulo Lollato, Wheat and Forages Specialist
Erick DeWolf, Extension Plant Pathologist