Wheat: Canada Prairie Spring Wheat

The Canada Prairie Spring (CPS) class of wheat was established in 1985 as a lower protein alternative to the Canada Western Red Spring (CWRS) class. The CPS class was originally known for its medium protein, medium kernel hardness and medium dough strength properties, which was desirable for special end uses. Furthermore, due to its higher starch content and lower protein concentration in comparison to CWRS wheat, CPS wheat has recently become recognized as a viable feedstock for ethanol production.

CPS wheat yields up to 20 per cent higher than current CWRS wheat varieties, but there is a wide range in each class. The economic advantage of growing the high-yielding varieties of the CPS class will depend upon delivery opportunities and its comparative price to other classes of wheat. The price of CPS wheat has traditionally been lower than the price of top grades of CWRS.

The CPS class has two sub-classes based on red and white kernel colour:

1. Canada Prairie Spring Red (CPSR)
2. Canada Prairie Spring White (CPSW)

Canada Prairie Spring Red (CPSR)

Current varieties in the CPSR sub-class have:

• Medium to strong dough strength properties;
• Medium protein content; and
• Hard kernels.

CPSR can be used alone or in blends for a wide range of products, including flat breads, crackers and noodles. CPSR has good milling characteristics and bread-making properties.

Canada Prairie Spring White (CPSW)

Current varieties in the CPSW sub-class have:

• Medium to strong dough strength properties;
• Low to medium protein content; and
• Medium-hard kernels.

CPSW wheat provides high flour extraction rates. CPSW can be used for a wide variety of low volume breads. Some markets prefer the whiter flour colour produced from milling white wheat.

Varieties

In recent years, production of CPSW has been extremely low. Continued breeding and variety development have resulted in increased yield, earlier maturity, improved resistance to pre-harvest sprouting, and enhanced disease resistance. The Varieties of Grain Crops publication no longer reports on varieties of CPSW. Please contact the ministry's Provincial Specialist, Cereal Crops for more information.

Seeding date

The best seeding date for CPS wheat is similar to that for CWRS wheat. However, the maturity of CPS varieties is one to four days later than many CWRS under normal conditions. Therefore, earlier seeding is recommended where the growing season is shorter, because early fall frosts are a risk for the later-maturing CPS varieties. When seeding is delayed, the maturity difference between the CPS and CWRS varieties may increase, which increases CPS cultivars' risk to early fall frost damage.

Seeding rate

Aim for the same plant population as CWRS varieties (20 to 25 plants per sq. ft. or 215 to 270 plants per sq. m). CPS kernels are larger than CWRS kernels and weights typically range between 40 and 43 grams per 1,000 kernels (TKW). Seed weight can vary, depending on the source. Therefore, it is strongly recommended that seeding rates are determined on the basis of intended plant density, TKW and the per cent survival. The formula below provides an approximate seeding rate calculation.

Seeding rate (lb. per acre) = plants per sq. ft. x TKW (g) x 10 (conversion factor*) ÷ per cent survival

(*The conversion factor is used to convert to appropriate units.)

Example: 25 (plants per sq. ft.) x 43 (g) x 10 ÷ 85 (per cent survival) = 126 lb. per acre (seeding rate).

Per cent survival is the percentage of seeds planted that germinate and emerge into vigorous seedlings. Note that it is important to determine kernel weight and know the germination status of your seed.

The seeding rate calculator on the Alberta Agriculture and Forestry website provides an easy method to determine appropriate seeding rates.

Higher plant densities are typically used when moisture conditions are good. That's why seeding rates in the Black soil zone tend to be higher than those in the drier Brown soil zone. Seeding on the high end of the recommended range may reduce the number of tillers and shorten time to maturity under sub-optimal conditions.

Ensure that seed is tested not only for purity, germination and vigour, but also for seed-borne diseases. Those CPS varieties rated "poor" for loose smut in the current Varieties of Grain Crops should be treated for the control of this disease. See the Guide to Crop Protection for more information on seed treatments.

Seeding

Seeding depth should be approximately four to six cm (1.5 to 2.5 in.). Shallow seeding can speed up emergence, reduce common root rot infection and reduce the competitive stresses from weeds.

Fertility

Wheat yield will depend primarily on the amount of moisture and nutrients available to the crop, as well as growing conditions. Soil testing and subsoil moisture measurement are useful tools for determining a realistic target yield and type and amount of nutrients needed to achieve the realistic target yield for each field. Typically, a 40 bushel per acre wheat crop will take up about:

• 76 to 93 lb. (34.6 to 42.3 kg) per acre of N;
• 29 to 35 lb. (13.2 to 15.9 kg) per acre of P₂O₅;
• 65 to 80 lb. (29.6 to 36.4 kg) per acre of K₂O; and
• eight to 10 lb. (3.6 to 4.5 kg) per acre of S.

When applying the fertilizer in the seed row, follow the Guidelines for Safe Rates of Fertilizer Applied with the Seed.

Weed control

Implementing an integrated weed management strategy throughout the rotation will help to reduce the impact and costs due to weeds on an ongoing basis. CPS and CWRS wheat types are not usually differentiated on herbicide labels. When using a herbicide for the first time on a new variety, the application should be limited to a small acreage to evaluate tolerance if the herbicide indicates a varietal sensitivity, or is not recommended for durum.

Only use herbicides that are registered for use on spring wheat when spraying CPS varieties for weed control.

Refer to the Guide to Crop Protection for registered herbicides for wheat, as well as re-cropping restrictions.

Insect management

Grasshoppers, wheat stem sawfly, and wheat midge are all potential insect pests of CPS wheat. Damage will vary depending on the level of infestation in a field, climatic conditions, and crop stage.

Like other cereal crops, CPS wheat will be affected by grasshopper feeding on green tissue. All crop stages are susceptible. If grasshopper populations exceed economic thresholds, insecticides may be considered.

Some CPS wheat varieties are also susceptible to wheat midge damage, through a reduction in yield or grade. There are a few CPS varieties that have tolerance to wheat midge and are sold as varietal blend (VB). As with other wheat varieties, CPS wheat is susceptible to midge from when the head becomes visible as the boot splits, until anthesis (flowering). Insecticides are available for the control of wheat midge if required.

CPS wheat is susceptible to wheat stem sawfly cutting. Sawfly management is through non-chemical methods. If wheat is grown in heavily infested areas, solid-stemmed varieties are the best management option. Unfortunately, no solid-stemmed CPS wheat varieties are currently available.

Disease management

Diseases affecting other classes of wheat may also be a problem on CPS wheat, including:

• Root rots:
• Tan spot;
• Septoria leaf blotch;
• Rusts;
• Ergot;
• Smuts; and
• Fusarium head blight.

Breeding efforts are continuously developing improved varieties. Refer to the Varieties of Grain Crops for the latest disease resistance ratings.

Seed treatment is recommended to control loose smut and to protect against rots caused by soil-borne diseases. Foliar fungicides are available to protect against leaf diseases. Begin scouting the field at the tillering stage to monitor early leaf disease development. Apply a fungicide at flag leaf emergence if disease symptoms are spreading. Foliar fungicides do not usually provide sufficient control of fusarium head blight. No fungicide options exist for ergot.

Harvest

CPS varieties should be swathed at the same maturity stage as CWRS varieties. It is usually safe to begin swathing when kernel moisture content is 35 per cent or less. Straight combining can reduce sprouting damage in wet harvest conditions.

Irrigation

Lodging and disease resistance are important considerations for production under irrigated conditions. Typically, you should seed before May 7, because CPS wheat takes longer to mature (120 days or longer under irrigation). Target population is 31 plants per sq. ft. (334 plants per sq. m). Critical stages for moisture are at tillering (four to five leaf stage) and at flowering. Maintain soil at more than 50 per cent available moisture. Aim for 40 mm (1.5 in.) per week from flag leaf to soft dough.