Winter Wheat Blends as a Potential Method of Enhancing Genetic Diversity, Pest Tolerance, and Yield Stability, thus reducing Farmer Risk

Project Overview

Project Type: Research and Education
Funds awarded in 2003: $126,000.00
Projected End Date: 12/31/2006
Region: North Central
State: Nebraska
Project Coordinator:
Lenis Nelson
University of Nebraska

Annual Reports


  • Agronomic: wheat


  • Education and Training: demonstration, on-farm/ranch research
  • Farm Business Management: feasibility study
  • Natural Resources/Environment: biodiversity
  • Production Systems: general crop production


    Wheat varieties which contain complementary genetic traits but similar phenotypic traits were blended together in equal proportions and compared to the variety components grown separately. Six blend combinations were tested in 50 trials over a three-year period. All six blends were superior to the average of their components when averaged over the 50 trials. Nearly 50% more individual locations/blend combinations showed increases than decreases of blends vs. components. Yield increases were up to 1.7 bushels per acre for the best blend.


    Organic and low input production of winter wheat is dependent on varieties that are adapted to a given region, that maintain high end-use quality, resist diseases and insects, and have a high yield level. Most wheat varieties cannot meet all these requirements of pest resistance, yield potential, and end-use quality. A highly successful winter wheat variety has its usage rapidly expand over a large geographic area of the wheat producing part of the Great Plains, dramatically reducing bio-diversity. When a variety begins to occupy over 20% of the area from Oklahoma to South Dakota, the resistance to diseases and insects quickly breaks down. This makes the most successful varieties more susceptible than less successful varieties. Thus, the yield stability is decreased across the whole region. The quick demise of a variety causes more strain on the wheat production system because of the time it takes to get a new variety with new sources of resistance into new varieties. Unfortunately, there is a lag of several years before enough seed of a new variety can be developed. Winter wheat production would be more sustainable and profitable if the most successful varieties could be sustained at a high yield level for more years. Several area farmers have asked if blends could be used to maintain bio-diversity and maintain high yield potential. This presents several beneficial effects. It presents the attacking organisms with a more diverse target, which makes it more difficult for them to mutate and build up a high number of tolerant types. Blends also give the opportunity for varieties to complement each other making them more stable from one year to the next. It may be possible to modify the blends by using a widely adapted variety as a base and adding locally adapted varieties which would change from one area to the next.

    Farmers in China have used blends of rice for many years. A study of this practice by scientists shows that blends of rice have stabilized yields by eliminating disease and insect catastrophes. They have also eliminated the use of fungicides while maintaining yields. Blends have also been used successfully in peanut in Florida and soybean in India. Wheat blends have been used in Tunisia. Kansas State University has tested winter wheat blends for several years. Our Nebraska variety tests have only included pure lines and many times the highest yielding variety one year is not the highest yielding the next year. However, usually the top three varieties continue to perform in the top three the next year. Thus, by using blends, we can gain make better use of the top yielding varieties.

    Much research and fine tuning is necessary to obtain the greatest advantage from blends. From a theoretical approach, a number of blends could be proposed which take advantage of genetic diversity while maintaining similar maturity and height characteristics. Another advantage can be traced to end-use quality. Since nearly all varieties have some quality weaknesses, the use of blends could improve the overall quality of the crop. Once several blends have been made based on the theoretical advantages, they would need to be field tested. In order to determine the potential for blends, tests need to be conducted over a large number of farms for three years. The blends would also need to be compared with a large number of the best varieties for each part of the region. All of the blends would consist of hard red winter wheat so the blends would not encounter marketing problems for the buyers of the grain.

    Project objectives:

    The first goal was to publicize the concept of wheat variety blends, demonstrate the feasibility of blends to compete with pure lines, and learn about the behavior of various blends compared to their pure line components.

    The second goal was to help producers utilize wheat blends to increase the bio-diversity of their farms and the region. Annual survey of wheat varieties planted will be used to monitor this. The target area is the wheat production region of Nebraska (1.5 million acres).

    The third goal was to have acceptance of variety blends on producer's farms. Acceptance could change the emphasis of the wheat breeding program and improve economic conditions for rural communities as well as individual farmers.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.