|Gulya Jr, Thomas|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/28/2007
Publication Date: 1/18/2008
Citation: Jiuhuan, F., Liu, Z., Seiler, G.J., Gulya, T.J., Jan, C.C. 2008. Introgressing Sclerotinia stalk rot resistance from diverse wild perennial species into cultivated sunflower. 6th Annual Sclerotinia Initiative Meeting, January 23-25, 2008, Bloomington, MN. p. 14.
Technical Abstract: Cultivated sunflower lacks a sufficient level of resistance to Sclerotinia stalk rot, but high levels of resistance have been reported in perennial Helianthus species. The objectives were to 1) reconfirm the resistance in perennial Helianthus species and in previously developed interspecific amphiploids, and 2) transfer the resistance genes into a cultivated background. We have completed a 3-year project funded by the Sclerotinia Initiative and are proposing a new 4-year project based on the progress of the past 3 years. In the first two years of the previous project, field and greenhouse evaluations indicated excellent stalk rot resistance in six amphiploids. Resistant amphiploids were crossed with HA 410 in 2006, and BC2F1 plants with chromosome numbers ranging from 2n=34 to 41 were established in the greenhouse for further backcrosses or seed increase for field evaluation. In addition, interspecific F1 progeny were produced between stalk rot resistant hexaploid H. californicus and H. schweinitzii and HA 410. The F1 plants were resistant to stalk rot and had good backcross seed set. Continued backcrossing with HA 410 resulted in BC4F1 plants with improved pollen and seed fertility and with 2n chromosome numbers between 34 and 40. These progenies can be further backcrossed or seed increased for field evaluation. In the third year (2007), stalk rot resistant diploid perennial H. maximiliani, H. giganteus, and H. grosseserratus were crossed with HA 410 and F1 progeny obtained via embryo rescue. A sufficient number of backcrossed seeds were obtained to continue the project. In summary, wild perennial Helianthus species and interspecific amphiploids involving wild perennial Helianthus species were found to be highly resistant to Sclerotinia stalk rot. Embryo rescue proved to be essential for the establishment of the F1 interspecific hybrids. F1 hybrids had low pollen and seed set fertility but sufficient backcrossed seed were obtained for most crosses. Backcrossed progeny with 2n=34 were obtained from all selected resistant sources and selfed to produce seed for replicated field tests. The continuation of this project will produce a large number of segregating families for selecting resistance to the most devastating disease of sunflower. In addition, understanding the genetics of the resistance and the follow-up QTL molecular mapping will provide useful tools for marker-assisted selection for Sclerotinia resistance breeding.