Submitted to: The Plant Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/13/2006
Publication Date: 1/1/2007
Citation: McGrath, J.M., Trebbi, D., Fenwick, A.L., Panella, L.W., Schulz, B., Laurent, V., Barnes, S., Murray, S.C. 2007. An open-source first-generation molecular genetic map from a sugar x table beet cross and its extension to physical mapping. The Plant Genome. 47(1):S27-S44.
Interpretive Summary: Genetic maps are essential for modern breeding because the genes controlling the expression of agronomic traits are most often found on chromosomes linked with many other characters such as molecular markers. Many molecular marker maps are available for sugar beet, but their utility is low because the markers themselves have not been released to the public, necessitating a public effort to map the sugar beet genome. This work describes the development of the first sharable molecular marker map and publishes the sequence of a number of these molecular markers for general use by sugar beet scientists. These markers now allow more in depth investigations on the inheritance and linkage of agronomic traits important to sugar beet growers.
Technical Abstract: In sugar beet, many linkage maps have been constructed, but the availability of markers continues to limit utility of genetic maps in public domain programs. Here a framework genetic map is presented that is expandable and transferable to research programs interested in locating their markers on a consensus map. In its current framework, the primary markers used were Amplified Fragment Length Polymorphisms and these were anchored to Butterfass chromosome-nomenclature linkage groups using linkage group specific Simple Sequence Repeat (SSR) markers. Thus, a common framework has been established that anchors 319 markers, including 10 newly described SSR markers, over a total 512.1 cM among the nine beet linkage groups. The source of the mapping population was a sugar X table beet population, and this is the first report of a map constructed with a relatively wide cross in Beta vulgaris. Two linkage groups showed segregation distortion, predominantly in favor of the maternal sugar beet parent, suggesting functional genetic divergence between crop use types. Physical segments of the beet genome that carry mapped markers have been identified, demonstrating that physical and genetic mapping are facile and complementary applications for beet improvement.