SUNFLOWER GERMPLASM DIVERSIFICATION AND CHARACTERIZATION UTILIZING WILD SUNFLOWER SPECIES, CYTOGENETICS, AND APPLIED GENOMICS
Location: Sunflower Research
Title: Progress on the introgression of Sclerotinia resistance genes from wild perennial Helianthus species into cultivated sunflower
Submitted to: ARS Sclerotinia Initiative Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: December 17, 2011
Publication Date: January 19, 2011
Citation: Liu, Z., Cai, X., Seiler, G.J., Gulya, T.J., Rashid, K.Y., Jan, C. 2011. Progress on the introgression of Sclerotinia resistance genes from wild perennial Helianthus species into cultivated sunflower. ARS Sclerotinia Initiative Annual Meeting, January 19-21, 2011, Bloomington, MN. p. 25.
The necrotrophic fungus Sclerotinia sclerotiorum (Lib.) de Bary attacks sunflower (Helianthus annuus L.) causing root, stalk, and head rot, and is one of the most damaging and difficult-to-control sunflower diseases. Some wild perennial Helianthus species have been identified to contain abundant resistance genes to this fungus. The objectives of this project were to transfer Sclerotinia head and stalk rot resistance from resistant wild perennial haxaploid and diploid Helianthus accessions, and interspecific amphiploids into cultivated sunflower, via the traditional backcross method. BC4F3 plants (2n=34-37) of H. californicus/HA 410 crosses were obtained with improved pollen fertility and seed set in 2008 for hexaploid species. The backcrossing of hexaploid H. schweinitzii with HA 410 obtained more than 40 BC3F2 and BC4F1 plants in 2010. Five amphiploids with high resistance to stalk and head rot were crossed with HA 410, and BC2F2 /BC3F1 plants (2n=34-36) were obtained in the greenhouse in 2008, and with further backcrossing and selfing in 2008 and 2009 produced seed for the 2009 and 2010 field evaluations. For Sclerotinia resistant diploid perennial species, H. maximiliani, H. giganteus, H. grosseserratus, and H. nuttallii, selfed and/or backcrossed progenies with 2n=34-35 chromosomes were obtained in 2008 with seed increased in the field in 2009 and 2010. In 2009, replicated field tests with 163 and 313 progeny families screened for head and stalk rot resistance at Carrington, ND, respectively, showed good introgression of resistance genes. These materials were planted 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 309 and 413 progeny families were screened for head and stalk rot resistance, respectively. However, due to unexpected midge damage and adverse environmental conditions at Carrington, most of the tests for head rot failed to produce usable results in 2010. For stalk rot, 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 crosses with HA 410 and HA 451. HA 451 is tolerant to both head and stalk rot. These new crosses will provide more diverse resistance genes for developing Sclerotinia resistant germplasm.