|Gulya Jr, Thomas|
Submitted to: Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/10/2006
Publication Date: 3/10/2006
Citation: Jan, C.C., Feng, J., Seiler, G.J., Gulya Jr, T.J. 2006. Amphiploids of perennial Helianthus species x cultivated sunflower possess valuable genes for resistance to Sclerotinia stem and head rot. 28th Sunflower Research Workshop, January 11-12, 2006, Fargo, ND. Available: http://www.sunflowernsa.com/research/research-workshop/documents/Jan_Amphiploids_06.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: Field evaluation of stem and head rot resistance using artificial inoculation was conducted using interspecific amphiploids of wild perennials H. grosseserratus, H. hirsutus, H. maximiliani, H. nuttallii, H. strumosus crossed with P21, intercrossed amphiploids involving H. divaracatus and H. grossesserratus, and BC1F1 of amphiploid involving H. strumosus. All the amphiploids had better stem rot resistance than the most stem rot tolerant check HA 410. Due to the late flowering of most amphiploids, head rot resistance was observed only in an amphiploid of H. nuttallii x P21, which segregated 11 resistant and 16 susceptible plants compared to all 17 plants of the tolerant check HA 441 being susceptible. These amphiploids will provide new resistance genes to develop germplasm lines superior to HA 410 and HA 441 for stem rot and head rot resistance, respectively.