Creating your own winter wheat variety mixtures – methods and experiences

The Innovation Center for Organic Farming, in collaboration with two organic farmers, tested two methods for creating custom winther wheat variety mixtures.

By Karen Munk Hansen

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Variety mixtures are generally more robust than pure stands with regard to disease resitance and yield. If the varieties in a mixture differ in growth habits, the mixture may also provide better weed suppression than the same varieties grown as pure stands.

Commercially prepared variety mixtures are available, but if you have specific requirements, you can also create your own. When purchasing a commercial variety mixture, the component varieties have been evaluated for their suitability in mixtures, and the seed is supplied as a single blended product. If you prepare the mixture yourself, you have greater flexibility in selcting the varities, but you are also responsible for evaluating their suitability and managing multiple seed deliveries.

Three varieties in the mixture

In a on-farm demonstration trial conducted with two organic farmers, mixtures of the winther wheat varieties Pondus, Pacman and Fritop were sown in equal proportions (1:1:1). The varieties were selected for the following reasons:

Pondus is marketed for both conventional and organic production and has consistently achieved high yields in the Danich National Variety Trials® over the past five years under conventional management. It has a prostate growth habit, which may provide good ground cover and suppress weeds effectively during autumn.
Pacman has produced top yields in the Danish National Variety Trials® in recent years. As of September 2025, it has been reclassified into susceptibility group 3 for yellow rust.
Fritop has a relatively modest yield potential when grown as pure stand, but it is taller than the other two varieties. This provides better weed suprpression but also increases the risk of lodging. It is awned, making it easy to identify from the heading stage onwards.

At both sites, the variety mixture was sown using a 6-metre Väderstad Spirit seed drill. The demonstration strips were 30-36 metres wide.

The seed can be delivered directly to the field, with the varieties loaded into the seed drill in alternative layers

The varieties can also be mixed on the barn floor using a front loader. This method produces a uniform mixture.

Experimental design

On-farm demonstration trials at two locations
Two treatments: Seed mixed on the barn floor before sowing, and seed mixed by layering the varieties in the seed hopper
Plots: Four to six drill widths of each treatment, with two replicates at each location
Target plant population and sowing depth were according to the normal practice of the host farmers.

Two mixing methods tested under practical farming conditions

The variety mixtures were prepared using two different methods:

One involving mixing the seed on the barn floor with a front-end loader before loading it into the seed drill
The other involved placing the three varieties directly into the seed hopper in alternating layers and allowing the them to mix during sowing

The performance of the two methods was assessed by evaluating the crop in the field.

The first method is more labour-intensive and requires transport ing seed when refilling the seed drill. The second method can be carried out directly in the field. However, experience showed that the seed drill had to travel approximately 100 metres before a funnel effect develops in the seed hopper, resulting in an even distribution of the varieties.

Advantages and disadvantages of the two methods

Both mixing methods worked in practice with three varieties, apart from the somewhat uneven establishment at the start when the seed was layered in the hopper. If a larger number of varieties is to be mixed, preparing the mixture on the barn floor is likely to produce the most uniform result in the field.

Both methods have advantages and disadvantages, and each of the two host farmers preferred a different method.

Mixing on the barn floor

Mixing in seed drill

Additional mixing operation required before sowing

Transport required when refilling the seed drill

Greater risk of seed spillage

Suitable for mixing a larger number of varieties

Simple and labour-efficient

Seed can be delivered directly to the field

Lower risk of seed spillage

The mixture becomes uniform only after approximately 100 metres of sowing

The seed hopper should be refilled before it is completely empty

The seed rate should be recalibrated after the first few passes, once the mixture has become uniform

The variety Fritop has awns and is taller than the other varieties in the mixture. These distinct varietal differences make it easier to assess the quality of the seed mixture in the field

The grain in the first drill pass with seed mixing directly in the seed hopper is slightly lighter in colour. The variety Fritop was at the bottom of the hopper, resulting in an overrepresentation of this variety until the air-assisted mixing process became fully effective

National Variety Trials provide further knowledge

The variety mixtures performed very well at both demonstration trials. Overall, the incidence of fungal diseases was low, and no differences between the mixing methods were observed.

The demonstration trial design does not allow definitive conclusions to be drawn regarding the health status or weed competitiveness of the variety mixtures. However, additional evidence is expected from the Danish National Variety Trials conducted in 2025 and 2026, in which different variety mixtures and pure stands have been evaluated for yield, weed suppression, and disease susceptibility.

See the results from the 2025 Danish National Variety Trials (in Danish)

Technical note: Experiences with mixing winter wheat varieties for custom variety mixtures (PDF 15 pages) (in Danish)