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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Publications at this Location » Publication #151915
Title: EVALUATION OF ORNAMENTAL SUNFLOWER CULTIVARS FOR DISEASE RESISTANCE AND OIL CHARACTERISTICS

Author
item GULYA JR, THOMAS
item VICK, BRADY

Submitted to: European Conference on Biotechnology
Publication Type: Abstract Only
Publication Acceptance Date: 9/5/2003
Publication Date: 10/1/2003
Citation: Gulya Jr, T.J., Vick, B.A. 2003. Evaluation of ornamental sunflower cultivars for disease resistance and oil characteristics [abstract]. European Conference on Biotechnology.

Interpretive Summary: Commercial ornamental sunflower (Helianthus annuus) cultivars and USDA sunflower accessions with ornamental characteristics were evaluated for resistance to several diseases and for fatty acid composition to determine if ornamental types might serve as an untapped source of genes for oilseed improvement. All 80 commercial cultivars were susceptible in greenhouse tests to the most prevalent races (300, 700 and 733) of downy mildew (Plasmopara halstedii), with only three cultivars displaying resistance to race 100, the least virulent race. When tested with multiple races of rust (Puccinia helianthi), three commercial cultivars were uniformly resistant to races 700 and 733 in greenhouse trials. Ten of the 51 USDA sunflower accessions with ornamental characteristics (ray petal color, petal number) had resistance to one or more rust or downy mildew races, but all accessions were segregating for resistance. In field tests in South Africa, one USDA ornamental accession was immune to white rust (Albugo tragopogonis) out of 1100 Plant Introductions tested. None of the ornamental-type cultivars showed any usable level of resistance to Sclerotinia stalk rot or Phomopsis stem canker. Twenty-seven of the commercial cultivars and 51 USDA Plant Introductions were also analyzed for fatty acid composition, with most of the commercial cultivars having been grown in California, and the USDA accessions grown in Ames, IA. The total saturated fatty acid content of the entries ranged from 8.2% in PI 507906 to 18.7% in the commercial cultivar Lemon Aura, suggesting that there is sufficient genetic diversity among the cultivars to select for high or reduced saturated fatty acid content. In summary, commercial ornamental cultivars do not possess significant resistance to diseases such as rust, downy mildew, Sclerotinia wilt and Phomopsis stem canker, and are unlikely to help improve oilseed germplasm. However, the ornamentals should be considered as potential sources of germplasm for alteration of saturated fatty acid composition.

Technical Abstract: Commercial ornamental sunflower (Helianthus annuus) cultivars and USDA sunflower accessions with ornamental characteristics were evaluated for resistance to several diseases and for fatty acid composition to determine if ornamental types might serve as an untapped source of genes for oilseed improvement. All 80 commercial cultivars were susceptible in greenhouse tests to the most prevalent races (300, 700 and 733) of downy mildew (Plasmopara halstedii), with only three cultivars displaying resistance to race 100, the least virulent race. When tested with multiple races of rust (Puccinia helianthi), three commercial cultivars were uniformly resistant to races 700 and 733 in greenhouse trials. Ten of the 51 USDA sunflower accessions with ornamental characteristics (ray petal color, petal number) had resistance to one or more rust or downy mildew races, but all accessions were segregating for resistance. In field tests in South Africa, one USDA ornamental accession was immune to white rust (Albugo tragopogonis) out of 1100 Plant Introductions tested. None of the ornamental-type cultivars showed any usable level of resistance to Sclerotinia stalk rot or Phomopsis stem canker. Twenty-seven of the commercial cultivars and 51 USDA Plant Introductions were also analyzed for fatty acid composition, with most of the commercial cultivars having been grown in California, and the USDA accessions grown in Ames, IA. The total saturated fatty acid content of the entries ranged from 8.2% in PI 507906 to 18.7% in the commercial cultivar Lemon Aura, suggesting that there is sufficient genetic diversity among the cultivars to select for high or reduced saturated fatty acid content. In summary, commercial ornamental cultivars do not possess significant resistance to diseases such as rust, downy mildew, Sclerotinia wilt and Phomopsis stem canker, and are unlikely to help improve oilseed germplasm. However, the ornamentals should be considered as potential sources of germplasm for alteration of saturated fatty acid composition.