ARS | Publication request: Transferring Sclerotinia stalk rot resistance genes from wild Helianthus species into cultivated sunflower

Submitted to: Sunflower Research Forum
Publication Type: Proceedings
Publication Acceptance Date: March 24, 2011
Publication Date: March 24, 2011
Citation: Liu, Z., Cai, X., Seiler, G.J., Gulya, T.J., Khalid, R.Y., Jan, C.C. 2011. Transferring Sclerotinia stalk rot resistance genes from wild Helianthus species into cultivated sunflower. Proceedings Sunflower Research Forum, January 12-13, 2011, Fargo, ND. Available: http://www.sunflowernsa.com/research/searchable-database-of-forum-papers/default.asp#r

Interpretive Summary: The fungus Sclerotinia sclerotiorum (Lib.) de Bary attacks sunflower (Helianthus annuus) causing root, stalk, and head rot, and is one of the most damaging and difficult-to-control sunflower diseases. Wild perennial Helianthus species have been identified to contain an abundance of resistance genes to this fungus. Genetic analysis has indicated that Sclerotinia resistance is multigenic, and that resistance to basal stalk and head rot are not related. The objectives of this study were to: (1) transfer Sclerotinia stalk rot resistance from resistant wild perennial hexaploid and diploid Helianthus accessions, and interspecific amphiploids into cultivated sunflower, via the traditional backcross method; and (2) evaluate stalk rot resistance via field testing to identify progenies with higher levels of resistance. A two-year field evaluation for stalk rot resistance showed progeny families derived from all the stalk rot resistant sources were performing well, and the lines originally derived from head rot resistant sources also showed good stalk rot resistance. Detailed analysis for the stalk rot resistance of each progeny family and the possible introgression of the wild segments will be studied in future experiments.

Technical Abstract: Replicated field tests of 313 progeny families screened for stalk rot resistance at Carrington, ND in 2009 showed good introgression of resistance genes. These materials were planted again in 2010 for a second year of field evaluation, as well as the new families with seed increased in 2009. In 2010, replicated field tests with a total of 413 progeny families were screened for stalk rot resistance. Two years of data for the 313 entries for stalk rot resistance are reported. We have decided to eliminate the heavily infected families from both years, and further evaluate only the lightly infected families in 2011. Molecular tracking using SSR markers suggested a higher frequency of gene introgression when perennial diploids species were used. In 2010, eight accessions from three diploid and one tetraploid perennial species were established in the greenhouse for crossing with HA 410 and HA 451. The new crosses will provide more diverse resistance genes for developing Sclerotinia resistant germplasm.