Submitted to: Potato Association of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/20/2004
Publication Date: 1/20/2005
Citation: Zhang, R., Haynes, K.G., Christ, B.J. 2005. QTLs for partial resistance to early blight and foliage maturity in a full-sib diploid potato family from Solanum phureja x S. stenotomum. Amer. J. Potato Res. 87:88. (Abstract). Interpretive Summary:
Technical Abstract: Early blight (EB), caused by the fungus Alternaria solani Sorauer, is an important potato disease worldwide. Currently, fungicides are used to manage EB since few commercial cultivars of potato (Solanum tuberosom L.) have high levels of resistance. Those cultivars with moderate resistance are also late maturing. A full-sib family from Solanum phureja S. stenotomum was developed and evaluated for EB resistance as well as foliage maturity. In addition, a genetic map with amplified fragment length polymorphism (AFLP) markers and simple sequence repeat (SSR) markers was constructed for this family. It covered 925 centi Morgans (cM) of the potato genome with an average distance of 4.5 cM between adjacent markers. Quantitative trait loci (QTLs) for partial resistance to EB and QTLs for foliage maturity were mapped using "Multiple-QTL models" (MQM) method with putative QTL markers from interval mapping as cofactors. Five QTLs on chromosome IV, V, IX, XI and XII were identified for EB resistance that collectively explained 62.2% of the total phenotypic variation. Three QTLs on chromosome IV, V and VI were identified for foliage maturity that collectively explained 97.5% of the total phenotypic variation. Two QTLs for EB resistance on chromosome IV and V were mapped in the same or closely linked regions of QTLs for foliage maturity. The other three QTLs for EB resistance on chromosome IX, XI and XII, which accounted for 33.1% of the total phenotypic variation and were not linked to foliage maturity, have the potential to improve early blight resistance using marker-assisted selection.