SUNFLOWER GERMPLASM DIVERSIFICATION AND CHARACTERIZATION UTILIZING WILD SUNFLOWER SPECIES, CYTOGENETICS, AND APPLIED GENOMICS
Location: Sunflower Research
Title: Developing Sclerotinia Resistant Sunflower Germplasm Utilizing Wild Perennial Helianthus Species
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 11, 2010
Publication Date: March 1, 2010
Citation: Liu, Z., Cai, X., Seiler, G.J., Gulya, T.J., Rashid, K.Y., Jan, C. 2010. Developing Sclerotinia Resistant Sunflower Germplasm Utilizing Wild Perennial Helianthus Species [abstract]. Sunbio 2010. 8th European Sunflower Biotechnology Conference, March 1-3, 2010, Antalya, Turkey. p. 26.
Cultivated sunflower lacks a sufficient level of resistance to both Sclerotinia stalk and head rot, but abundant resistance in perennial Helianthus species has been confirmed. The objectives of this project were to transfer Sclerotinia head and stalk rot resistance genes from wild perennial hexaploid and diploid Helianthus accessions and interspecific amphiploids into cultivated sunflower. Interspecific F1 hybrids were produced between stalk rot resistant hexaploid H. californicus and H. schweinitzii and cultivated inbred line HA 410, and with continued backcrossing of H. californicus crosses with HA 410 and selfing resulting in BC4F3 plants with improved pollen and seed fertility and with 2n chromosome numbers between 34 and 37 in 2008. Further backcrossing and selfing in 2008 increased seed for field evaluation in 2009. Five amphiploids highly resistant to stalk and head rot were crossed with HA 410 in 2006, and BC2F2 /BC3F1 plants with chromosome numbers from 2n=34 to 36 were obtained in the greenhouse in 2008, and further backcrossed and selfed to produce seed for 2009 field evaluation. Crosses between NMS HA89 and head rot resistant H. maximiliani and H. nuttallii were backcrossed with cultivated inbred line HA 441 and advanced to BC1F3 and BC2F3 generation in the field in 2008 and 2009 for seed increase. In 2007, stalk rot resistant diploid perennial H. maximiliani, H. giganteus, and H. grosseserratus were crossed with HA 410 and their BC1F2 /BC2F1 progenies with 2n=34 to 35 chromosomes were obtained in 2008. Their selfed BC1F3 and BC2F2 progeny were grown in the field in 2009 for seed increase. Replicated field tests with 163 and 313 progeny families were screened for head and stalk rot resistance in 2009, respectively. The results indicated moderate to good head and stalk rot resistance, suggesting successful gene introgression. Molecular tracking studies using SSR markers indicated high polymorphism between wild resistant donors and the cultivated recurrent parents, and the retention of markers specific to resistant donors was higher for progenies from diploid perennials than from hexpaloid or interspecific amphiploids, suggesting a higher frequency of gene introgression when perennial diploids species were used. Resistant lines identified in 2009 will be retested in 2010 and the results will be used to select lines for germplasm release, providing new resistance genes to further enhance Sclerotinia resistance in the sunflower crop. Selected resistant lines from each source will be used to develop QTL mapping populations with the ultimate goal of identifying major QTLs for use in future marker-assisted-selection. New crosses between additional resistant sources of hexaploid and diploid perennial Helianthus accessions with cultivated sunflower will be initiated in 2010. Protocol of genomic in situ hybridization (GISH) distinguishing chromosomes of perennial Helianthus species and cultivated sunflower has been established, providing an additional tool for studying gene transfer.