USDA CSREES Supports National Coordinated Effort in Barley Improvement

With the price of small grains going through the roof, maybe the large seed companies will start thinking about breeding wheat and barley.  But today, the breeding of these crops is still done primarily in the public sector.  Most of the original breeding programs for major crops were established at land grant universities.  Today, however, many of the breeding programs for major crops like corn, soybeans and cotton are done in the private sector where the source germplasm can be kept proprietary and there is substantial profit to be made from derived varieties.

Breeding requires a long-term commitment because it usually takes from 8-12 years to produce a variety from start to finish.  Thus, these programs also require sustained funding commitments, but, unfortunately, support for public-sector breeding has declined dramatically in recent years. Recently, the USDA CSREES (Coordinated State Research, Education and Extension Service) initiated Coordinated Agriculture Projects or CAPs to foster multi-state and multi-institution cooperative projects to support breeding efforts of public sector programs.  The availability of CAP funding creates a means to help support long-term breeding efforts in U.S. institutions. As such, CAPs provide a new streamlined model for a national, not state-oriented, approach to breeding that leverages the efforts of a diverse group of individuals and institutions.  In 2003, US barley researchers competed for and were successful in obtaining a CAP for barley.  The overall theme of Barley CAP, a community of 30 researchers at 19 institutions, is to integrate and utilize state-of-the-art genomic tools and approaches in plant breeding programs, thereby facilitating the development of superior barley cultivars barley for food, feed and brewing.   

Plant breeders respond to the needs of producers and industry by trying to develop new varieties as quickly as possible. The speed by which breeders can release new varieties depends on their ability to identify or select for superior performing lines. Conventional breeding has relied on selection based on phenotype, i.e. the observable qualities of a plant.  Barley CAP is developing selection tools that will enable breeders to select based on genotype or the actual genes contributing to the phenotype in a given breeding line.  The major problem with phenotypic selection is that a breeding line does not always perform or have the same phenotype at different times or in different environments.  For example, the New York Giants front office was probably not very impressed with the phenotype of Eli Manning after the first two games of the season and or playing the Minnesota Vikings! However, his “football” phenotype changed dramatically during the latter part of the season, when he eventually became Super Bowl champion and MVP.  When breeders can use information about the genotype of breeding lines, they can pick the “Eli and Peyton Mannings” more often, even if they are in a temporary slump.

Conventional barley breeding involves collecting lots of phenotypic data on many different traits. For example, in any of the 10 participating Barley CAP breeding programs, data is collected on a breeding line’s performance--its yield, height, heading date, grain plumpness, protein, and resistance to various diseases--through numerous field and greenhouse trials. Breeders can then use this information to select new varieties that have the best combinations of traits for the “complete package”.  But as previously stated, sometimes a breeding line will not always perform the same in all environments.  Thus, a breeder could throw out potentially useful lines based on preliminary data, which are not indicative of their true performance. 

To improve breeding procedures, it is desirable to also select lines based on the particular genes they possess, also known at the genotype.  Through advances in molecular biology, breeders can now use molecular markers, a type of “chemical signpost,” to essentially “barcode” individuals based on their DNA.  An example of genotypic data (“barcode”) for one of the barley chromosomes is given in Figure 1.  The four “columns” of the chromosome represent the barley varieties M133, Lacey, MNBrite and Rasmusson, respectively, while the 69 “rows” of the chromosome represent their “barcode” of molecular markers (e.g. #7193, 8398, 8836, etc.) or genotype.  If you compare the barleys based on their genotype, you can see that for many molecular markers along chromosome 6H, the four varieties are the same.  But in several places, there are important differences.

Figure 1. An example of genotypic data (“barcode”) for a barley chromosome.

We know through previous gene mapping studies that important genes for resistance to Septoria (a foliar fungal disease) and also for grain protein level reside on chromosome 6H. Line M133 can be phenotypically distinguished from Lacey, MNBrite and Rasmusson for its resistance to Septoria after inoculation with fungal spores.  But we can also tell that it is resistant based on its genotype pattern, i.e. at marker 8836.  Similarly, variety MNBrite can be phenotypically distinguished from the other three barleys for its higher grain protein by an expensive laboratory analysis referred to as the Kjeldahl procedure.  As with Septoria resistance, we can also tell that MNBrite has higher grain protein content based on its genotype pattern, i.e. at marker 5910.  Using a combination of phenotype and genotype (molecular marker) information, breeders can develop superior barley varieties faster and more efficiently than in the past.

 Although this actual example includes just two traits of importance, the CAP project will deliver to breeders the tools for genotyping barley lines for a wide array of traits for increased productivity, adaptation, quality, and resistance to biotic and abiotic stresses. 

To find out more about Barley CAP and it achievements, visit www.barleycap.org.

Contributors to this article: Kevin Smith, Brian Steffenson, University of Minnesota; and Peggy Lemaux, University of California at Berkeley.  Graphics assistance provided by Barbara Alonso, University of California at Berkeley.