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ARS Home » Southeast Area » Stoneville, Mississippi » Crop Genetics Research » Research » Publications at this Location » Publication #138669
Title: GENETICS OF RESISTANCE TO SCN

Author
item DIERS, BRIAN - UNIV OF ILLINOIS
item Arelli, Prakash

Submitted to: International Soy Conference
Publication Type: Proceedings
Publication Acceptance Date: 10/10/2002
Publication Date: 12/5/2002
Citation: Diers, B., Arelli, P.R. 2002. Genetics of resistance to scn. International Soy Conference.

Interpretive Summary:

Technical Abstract: Soybean cyst nematode (SCN) (Heterodera glycines Ichinohe) is estimated to cause the greatest yield losses to soybean [Glycine max (L.) Merr.] of any pest worldwide. The most recently published estimate is that SCN caused 7.6 million metric tons in yield losses in the US and almost 9 million worldwide during 1998. The two primary methods for controlling SCN are planting resistant cultivars and rotating to nonhost crops. Plant introductions (PIs) from the USDA Soybean Germplasm Collection have been screened for resistance to SCN and resistant lines have been identified. PIs 437654 and 438489B were found to be resistant to all five SCN races. Breeders have incorporated SCN resistance into most cultivars from only a limited number of PIs and can be traced to Peking, and PI 88788. More emphasis is now being directed to breeding with additional sources of resistance. Caldwell et al. (1960) found that the inheritance of resistance from Peking, an introduction from China, fit a three recessive gene model. Matson and Williams 1965 found a fourth resistance gene, dominant from Peking that is closely linked to the i locus, a gene that controls seed coat color. Genetic marker technology has presented the opportunity to map genes that provide resistance to SCN and other economically important traits, especially simple sequence repeat (SSR) markers. Many SCN resistance genes have been mapped with genetic markers as quantitative trait loci (QTL) from PIs. QTL that has been found across the most resistance sources is rhg1, which maps on linkage group (LG ) G, and has been mapped in PI88788, PI209332, PI437654, Peking, PI90763, and PI89772. A second gene that has been mapped in a number of sources is Rhg4, which maps on LG A. This QTL has been mapped in PI209332, PI437654, and Peking. These QTL can be used in marker assisted selection of SCN resistant varieties with durable resistance.