Location: Sunflower and Plant Biology ResearchTitle: Registration of two confection sunflower germplasms, HA-DM5 and HA-DM6, resistant to sunflower downy mildew
|MA, GUOJIA - North Dakota State University|
Submitted to: Journal of Plant Registrations
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/2/2019
Publication Date: 2/13/2020
Publication URL: https://handle.nal.usda.gov/10113/6949586
Citation: Qi, L.L., Ma, G.J., Seiler, G.J. 2020. Registration of two confection sunflower germplasms, HA-DM5 and HA-DM6, resistant to sunflower downy mildew. Journal of Plant Registrations. https://doi.org/10.1002/plr2.20014.
Interpretive Summary: Downy mildew (DM) is a widespread and devastating disease of sunflower that can cause up to 80% yield loss. The most economic and environmentally friendly way to reduced fungicide use for controlling DM disease is to develop DM-resistant sunflower lines. Due to the lack of DM resistance sources, confection sunflower is more sensitive to DM than oilseed sunflower. In this study, the DM resistance genes (Pl19 and Pl35) from two wild sunflower species were transferred into confection sunflower using backcrossing and marker-assisted selection. Two resulting sunflower lines, HA-DM5 and HA-DM6, were resistant to several modern DM pathotypes, which provides new sources for confection sunflower breeding programs.
Technical Abstract: Downy mildew caused by Plasmopara halstedii (Farl.) Berl. et de Toni is a primary biotic threat to sunflower production worldwide negatively impacting yield. Confection sunflower is more vulnerable to downy mildew than oilseed sunflower due to the lack of resistance sources. Germplasms HA-DM5 (Reg. No. xxxxxx, PI 687025) and HA-DM6 (Reg. No. xxxxxx, PI xxxxxx) were developed and released through the collaboration of the USDA-ARS and the North Dakota State University as new sources of resistance to downy mildew for confection sunflower. The backcross breeding method and DNA marker-assisted selection were used to develop HA-DM5 and HA-DM6. HA-DM5 is a BC2F3-derived BC2F4 maintainer selection from the cross of CONFSCLB1*2/CMS CONFSCLB1/Helianthus annuus accession PI 435414 with the DM resistance transferred from a wild H. annuus PI 435414. Phenotypic/molecular characterizations confirmed the presence of the DM resistance gene Pl19 located on sunflower chromosome 4 derived from PI 435414 in HA-DM5. HA-DM6 is a composite of seed from individual BC2F4 plants from the cross of CONFSCLB1*2/CMS CONFSCLB1/Helianthus argophyllus accession PI 494576. The DM resistance in HA-DM6 is controlled by a single dominant gene Pl35 located on chromosome 1 derived from wild H. argophyllus PI 494576. Both HA-DM5 and HA-DM6 confer resistance to several modern P. halstedii races currently identified in the United States and Europe. They provide new genetic diversity in addition to the few currently used DM-resistant inbred lines in confection sunflower ensuring protection from yield loss.