Importance of Variety Selection

Variety selection will dictate many of the decisions made in producing a wheat crop. Reactions to foliar diseases or insects, for example, will determine which pesticides are needed and when. Therefore, wheat farmers should carefully review variety characteristics and choose varieties that match their management style. This publication is designed to help wheat farmers make educated decisions about which varieties to grow. Additional information on yield potential of varieties can be found at OSU Department of Plant and Soil Sciences. 

Variety Developer and Licensee

The variety developer listed in this fact sheet indicates the breeding program that released the variety. This may or may not be the same organization marketing the variety (i.e., the licensee). The Oklahoma Crop Improvement Association (www.okcrop.com) can be contacted to obtain a listing of certified seed producers in Oklahoma. 

Lodging

Lodging ratings are based on a 1 to 5 scale with 1 indicating good straw strength and 5 indicating a greater propensity for lodging. This rating represents the genetic propensity for lodging and does not account for environmental factors, such as excessive nitrogen fertilization, which can also lead to lodging.

First Hollow Stem

First hollow stem is the growth stage when cattle should be removed from dual-purpose wheat pasture. A variety with a very late (VL) rating would offer one to two weeks more grazing in most years than a variety with a very early (VE) rating. 

Maturity

Maturity ratings are primarily based on observations within the OSU wheat breeding and variety testing programs. Spreading acreage among a range of wheat maturities is a good way to hedge against spring freeze injury, some wheat diseases and to spread harvest workload.

High Temperature Germination Sensitivity

Some varieties do not germinate well in hot soils and are not good candidates for early sowing. This chart uses a 1 to 5 scale to rate varieties with a 1 indicating a variety that will germinate well in hot soils and a 5 indicating a variety that does not germinate well in hot soils and should not be sown before October 1. For more information on this topic, consult OSU Extension Fact Sheet
PSS-2256 'Variation in Heat-Sensitive Germination Among Contemporary Hard Winter Wheat Varieties, 2019–2024.'

Coleoptile Length

The coleoptile is a rigid, protective structure that covers the emerging shoot to aid it in reaching the soil surface. If the coleoptile does not reach the soil surface, the plant will die. Therefore, coleoptile length should dictate planting depth. Coleoptile length is highly correlated to plant height at maturity and is shortened by hot soil conditions. In this chart, a rating of 1 indicates a relatively long coleoptile and a rating of 5 indicates a relatively short coleoptile. For more information on this topic consult OSU Extension Facts PSS-2256 'Factors Affecting Wheat Germination and Stand Establishment in Hot Soils.'

Hessian Fly

Hessian fly is a troublesome problem in some Oklahoma wheat fields. Hessian fly overwinters and oversummers in wheat residue, so it is most prevalent in, but not restricted to, continuous no-till wheat fields. Therefore, growers who no-till wheat after wheat should consider sowing varieties that have a resistant (R) or at least partially resistant (PR) rating. Likewise, growers who sow prior to October 1 might benefit from a variety with an R or PR rating, as early-sowing is a risk factor for Hessian fly. For more information on reducing the likelihood of Hessian fly infestation, refer to OSU Extension Fact Sheet EPP-7086 'Hessian Fly Management in Oklahoma Winter Wheat.'

Acid Soil Tolerance

  When soil pH drops below 5.5, essential plant nutrients can become unavailable, while some elements such as aluminum can become toxic. This publication uses a 1 to 5 scale, with 1 being most tolerant to low soil pH and 5 being least tolerant. Table 1 shows acceptable acid soil tolerance ratings for a range of pH conditions and production systems. It is also important to note in-furrow application of phosphorus at planting will increase early-season growth in most low-pH settings regardless of acid soil tolerance.

Wheat Streak Mosaic

Wheat streak mosaic virus is transmitted by the wheat curl mite. Mites oversummer on alternative host crops such as corn, volunteer wheat, and many grassy weeds. Wheat curl mites only live about seven to 10 days, so the best way to combat this virus is to make sure that any host crops are completely dead (not just sprayed) at least two weeks prior to sowing. Tolerance ratings are on a 1 to 5 scale, with 1 indicating tolerance and 5 indicating no tolerance. For more information on wheat streak mosaic virus, refer to OSU Extension Fact EPP-7328 'Three Virus Diseases of Wheat in Oklahoma.'

Wheat Soil-borne Mosaic/Wheat Spindle Streak Mosaic

Wheat soil-borne mosaic is a virus most prevalent in areas east of a line from Altus to Alva. Once a field has been infested with wheat soil-borne mosaic, the only alternative is to plant resistant varieties. Susceptibility ratings are on a 1 to 5 scale, with 1 being the most resistant and 5 indicating susceptibility. Fields with a history of wheat soil-borne mosaic should only be sown to varieties with a 1 or 2 rating. Wheat spindle streak mosaic is another virus disease that can be present with wheat soil-borne mosaic, but typically is not as damaging or as widespread in Oklahoma as wheat soil-borne mosaic. A few varieties are resistant to wheat soil-borne mosaic but susceptible to wheat spindle streak mosaic. These varieties are indicated with an asterisk in the comparison chart.

Septoria Leaf Blotch and Tan Spot

Septoria leaf blotch and tan spot are two foliar diseases of wheat that become more prevalent with adoption of conservation and no-till farming practices that leave wheat residue on the soil surface. These diseases rarely reach economic threshold levels in tilled Oklahoma wheat fields, but growers employing conservation or no-till farming practices should avoid planting varieties highly susceptible to these diseases. Ratings are on a 1 to 5 scale, with 1 indicating the most resistance and 5 indicating the least resistance.

Powdery Mildew

Powdery mildew is a very common foliar disease in Oklahoma, but one that rarely justifies a fungicide application by itself. Powdery mildew is generally most prevalent in early-sown wheat fields with adequate or surplus nitrogen fertility and dense plant canopies. Varieties with a 1 or 2 rating are not likely to be significantly impacted by powdery mildew. Varieties with a rating of 3 can have moderate amounts of powdery mildew if conditions are favorable for disease development. Varieties with a rating of 4 or 5 are most likely to have severe powdery mildew infestations and may require treatment.

Leaf Rust

Leaf rust probably has more impact on wheat yield in Oklahoma than any other foliar disease. While less aggressive than stripe rust, leaf rust occurs more frequently than stripe rust. For this reason, some producers choose to apply fungicides to control leaf rust if the crop yield potential and price warrant control.  Ratings for leaf rust are on a 1 to 5 scale, with 1 representing the greatest resistance to current disease races. It is important to note disease races can shift. Planting a variety with a rating of 1 will not eliminate the possibility of leaf rust, but will greatly decrease the likelihood that leaf rust reaches economic threshold levels. For more information on control of foliar diseases in wheat, consult OSU Extension Current Report CR-7668 'Foliar Fungicides and Wheat Production in Oklahoma.'

Stripe Rust

Stripe rust is the most aggressive of the foliar diseases listed in this publication. Fortunately, stripe rust is not a widespread problem every year, but this does make it difficult to accurately track genetic resistance to stripe rust. Ratings for stripe rust are on a 1 to 5 scale with 1 representing the greatest resistance to current disease races. It is important to note disease races can shift. So planting a variety with a rating of 1 will not eliminate the possibility of stripe rust, but will greatly decrease the likelihood that stripe rust reaches economic threshold levels. For more information on control of foliar diseases in wheat, consult OSU Extension Current Report CR-7668 'Foliar Fungicides and Wheat Production in Oklahoma.'

Variety Protection

Varieties listed as having PVP protection can only be sold as a certified class of seed. For more information on PVP protection laws, visit Farmer's Yield Initiative. 

Acknowledgements

Some variety ratings were adapted from Kansas State Publication MF-991 and 34 Star Publishing, Inc. publication 'Wheat Varieties for Kansas and the Great Plains 2018.' The authors greatly appreciate the input of the following individuals:

• Steve Ahring, AGSECO
• Sarah Battenfield, AgriPro
• Erick DeWolf, Kansas State University
• John Fenderson, WestBred
• Allan Fritz, Kansas State University
• Scott Haley, Colorado State University
• Drew Hendricker, Limagrain Cereal Seeds
• Ryan Klamfoth, Dyna-Gro
• Romulo Lollato, Kansas State University
• Clark Neely, Texas A&M University
• Jackie Rudd, Texas A&M University
• Guorong Zhang, Kansas State University

Tables. 2018 Wheat Variety Comparison Chart

David Marburger
Former Small Grains Extension Specialist

Bob Hunger
Extension Plant Pathologist

Brett Carver
Wheat Breeder

Tom Royer
Extension Entomologist and IPM Coordinator