|Gulya Jr, Thomas|
Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/5/2007
Publication Date: 2/5/2007
Citation: Feng, J., Seiler, G.J., Gulya Jr, T.J., Li, C., Jan, C.C. 2007. Sclerotinia stem and head rot resistant germplasm development utilizing interspecific amphiploids. 29th Sunflower Research Workshop, January 10-11, 2007, Fargo, ND. Available: http://www.sunflowernsa.com/research/research-workshop/documents/Feng_etal_Amphiploids_2007.pdf Interpretive Summary: Sclerotinia sclerotiorum (Lib.) de Bary is a major disease problem in the world's sunflower production. Cultivated sunflower and present-day hybrids lack an acceptable level of resistance to Sclerotinia. However, an abundance of wild Helianthus species are potential sources of genes for disease resistance and Sclerotinia is no exception. Interspecific amphiploids of crosses between wild perennial Helianthus species and cultivated line P21 have been produced and maintained by sib-pollination. These amphiploids, with their good backcross seed set, could be quickly utilized for the pyramiding of Sclerotinia resistance if proven to be resistant. The USDA sunflower breeding program at Fargo has released several inbred lines tolerance to Sclerotinia head rot and stalk rot, with HA 410 moderately resistant to stem rot and HA 441 moderately resistant to head rot. Our objective was to derive Sclerotinia resistance genes from these amphiploids and to pyramid them into the already tolerant HA 410 and HA 441 for stem rot and head rot, respectively. Field experiment with artificial inoculation indicated a high frequency of both stem rot and head rot resistant plants in five interspecific amphiploids, one intercross between two amphiploids, and one backcrossed progeny of an amphiploid, suggesting the existence of good resistance genes in those source material, and high possibility of future successful gene transfer.
Technical Abstract: Interspecific amphiploids have been confirmed as useful sources of resistance genes for both Sclerotinia stem rot and head rot based on our evaluations over two years, 2005 and 2006. The interspecific amphiploids include crosses of wild perennial Helianthus gracilentus, H. hirsutus, H. strumosus, H. grosseserratus, H. maximiliani, and H. nuttallii, crossed with P21, plus one intercrossed amphiploid involving H. divaricatus and H. grosseserratus. The results indicated that most amphiploids have better stem rot and head rot resistance than the tolerant checks HA 410 and HA 441, respectively. The good F1 seed set between the amphiploids and HA 410 or HA 441 provided a sufficient number of plants for further backcrossing and chromosome reduction toward the 2n=34 of the cultivated sunflower.