Submitted to: Molecular Breeding of Forage and Turf Conference
Publication Type: Book / chapter
Publication Acceptance Date: 11/1/2007
Publication Date: 6/11/2008
Citation: Brummer, E.C., Casler, M.D. 2008. Improving Selection in Forage, Turf, and Biomass Crops Using Molecular Markers. In: Yamada, T., editor. Molecular Breeding of Forage and Turf: The Proceedings of the 5th International Symposium on the Molecular Breeding of Forage and Turf. New York, NY: Springer. p. 193-209. Interpretive Summary: As DNA markers (small sequences of DNA that can be used to "fingerprint" plants) have become less expensive, more repeatable, and more universally applicable, their value in selecting better forage crop varieties has increased rapidly. Our paper explores several methods for incorporating DNA marker information into selection programs to produce improved varieties of forage crops. We provide specific details to demonstrate to forage breeders exactly how to combine plant-measurement data with DNA-marker data to improve the efficiency of selection and the rate of progress. These results will be of potential value to any forage breeder.
Technical Abstract: Selection of improved forage, turf, and bioenergy crops is optimized measurement of phenotype is rapid, inexpensive, and repeatable. Phenotyping remains the most difficult issue to resolve for many important traits, including biomass yield, abiotic stress tolerance, and long-term persistence. The identification of molecular markers may augment phenotypic selection if markers are identified that are closely linked to or at genes controlling the traits of interest. Simply inherited traits can be easily manipulated with marker assisted selection (MAS), but using markers in more complex situations requires additional thought. In this paper, we put the use of molecular markers into the context of typical perennial forage and turf breeding programs. Identifying markers based on bi-parental mapping populations is likely not the best way to implement a MAS program, although this approach is useful to introgress alleles from wild germplasm. Instead, a more practical approach may be the use of association mapping, measuring both phenotypes and markers directly on the plants in the breeding nursery. Complications of this method include the limited amount of information on linkage disequilibrium that is available for breeding populations, but the increasing availability of gene identification methods and the use of single nucleotide polymorphism (SNP) markers may enable the use of as-sociation mapping in many cases. Applying the information to breeding may be done to assist selection, to prescreen plants to determine those on which field-based phenotypic data will later be collected, and to make rapid off-season selections. The practical application of markers to the breeding program are discussed.