Submitted to: Crop Science Congress
Publication Type: Abstract Only
Publication Acceptance Date: June 28, 2004
Publication Date: September 26, 2004
Citation: Arelli, P.R., Diers, B.W., Concibido, V.C., Young, L.D. 2004. Progress in genetics and mapping for resistance in soybean [glycine max (l.) merril] to cyst nematode (hetrodere glycines ichinohe).. Crop Science Congress. p.129-131. 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 crop. The annual yield losses in 2002 are estimated to be nearly 9 million metric tons (2 Billion US $). Resistant cultivars reduce losses to SCN and are most cost effective and environmentally safe. Genetics of resistance are quantitative and complex. 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 mapped several major resistance quantitative trait loci in soybean germplasm including rhg1, Rhg4 and Rhg5. Predominantly, QTL for SCN resistance are mapped to linkage Groups A, G and J. Recently, rhg1 and Rhg4 have been reported to be cloned. Additional sources of resistance have been reported. Based on cluster analyses several genetically diverse lines have been identified. Unique QTL for SCN resistance are uncovered in diverse lines. These on-going efforts should reduce yield losses in soybean to SCN. Progress will be discussed.