Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/12/2005
Publication Date: 6/24/2005
Citation: Arelli, P.R. 2005. Progress in genetic mapping for resistance to cyst nematode in soybean.. Meeting Proceedings. Published on CD or www.agronomy.org.
Technical Abstract: Soybean [Glycine max (L.) Merrill] seed is a major source of protein for animal feed and oil for human consumption. It supplies approximately 65% of the world's protein meal and 25% of the world's edible oils. Worldwide, soybean cyst nematode (SCN: Heterodera glycines Ichinohe) is the most destructive pest on soybean crops. The annual yield losses due to SCN in 2002 were estimated to be nearly 9 million metric tons (2 Billion USD). Resistant cultivars reduce losses to SCN and are most cost effective and environmentally safe. Five major genes for resistance are designated and include rhg1, rhg2, rhg3, Rhg4 and Rhg5 from two different sources, Peking and PI 88788. Widespread use of these resistance genes caused major shifts in nematode populations and produced more virulent types. Broad-based resistance in soybean will reduce nematode shifts. Breeding for SCN resistance is tedious, time-consuming and inefficient. Genetic mapping and marker-assisted selection will improve the efficiency and provide durable resistance. Molecular markers have been used to map several major resistance quantitative trait loci in soybean germplasm including rhg1, Rhg4 and Rhg5. Predominantly, QTL for SCN resistance are mapped to linkage Groups A2, G and J. Additional sources of resistance have been reported. Unique QTL for SCN resistance occur in diverse lines including PIs 90763, 89772, 438489B, 404198A, and 468916. These ongoing efforts should reduce yield losses in soybean to SCN. Progress will be discussed.