|Gulya Jr, Thomas|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 1/4/2007
Publication Date: 1/10/2007
Citation: Feng, J., Seiler, G.J., Gulya, T.J., Li, C., Jan, C.C. 2007. Sclerotinia stem and head rot resistant germplasm development utilizing interspecific amphiploids. 5th Annual Sclerotinia Initiative Meeting, January 17-19, 2007, Bloomington, MN. p. 32. Interpretive Summary:
Technical Abstract: How to control Sclerotinia, a major fungal disease in cultivated sunflower, has always been a major concern for sunflower producers, breeders, and researchers. A considerable effort has been made to discover resistance genes in wild species and transfer them into the present-day hybrids, which are considered to possess insufficient resistance genes to Sclerotinia. Interspecific amphiploids of crosses between wild perennial Helianthus species and cultivated line P21 have been produced and used to provide resistant genes to a newly evolved race F of broomrape (Orobanche) in Spain. Similarly, these amphiploids, with their good backcross seed set, can quickly be utilized for pyramiding of Sclerotinia resistance genes, if they prove to be resistant. In 2005, seven interspecific amphiploids were evaluated at Fargo, ND, and all were found to be highly resistant to Sclerotinia stem rot compared to the tolerant check HA 410. In 2006, we repeated the evaluation of the same amphiploids for their resistance to Sclerotinia stem rot at Mapleton, ND, and head rot at Fargo, ND, using artificial inoculation in the field. Meanwhile, resistant amphiploid plants were crossed to stem rot tolerant HA 410 and head rot tolerant HA 441 for stem and head rot resistance gene pyramiding, respectively. Interspecific amphiploids have been confirmed as useful sources of resistance genes for both Sclerotinia stem rot and head rot based on our evaluation 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 result indicated that most amphiploids have better stem rot and head rot resistance than the tolerant check 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 chromosome number of cultivated sunflower. Based on our earlier success of transferring resistance genes from amphiploids for the broomrape resistance, we believe similar results can be achieved by using these amphiploids to develop sunflower germplasms superior to HA 410 and HA 441 for stem rot and head rot resistance, respectively.