2019 ASHS Annual Conference

Heliopsis helianthoides (L.) Sweet (aka false sunflower, heliopsis, smooth oxeye, and sunflower heliopsis) is an herbaceous perennial in the Asteraceae native to the prairies of North America. The combination of drought-tolerance, pest resistance, and long bloom season makes heliopsis an attractive choice for perennial gardens. New character traits in heliopsis have been identified and commercialized during the past 20 years and expands the utility of this species. The authors initiated a heliopsis breeding program in the late 1990s and developed a number of populations useful to document the inheritance of: red petal bases, variegated foliage, number of ray florets per inflorescence, ray corolla width, and overall inflorescence diameter. Variegated foliage is a qualitatively inherited trait controlled by a dominant allele at a single locus. Segregation of F₁ hybrids between ‘Loraine Sunshine’ (first variegated cultivar) with green-leaved selections fit a 1:1 variegated:green ratio, pointing to ‘Loraine Sunshine’ being heterozygous for the trait. Variegated F₁ offspring were planted in isolation (heliopsis possesses sporophytic self-incompatibility) and their offspring fit a 3:1 variegated:green ratio, further supporting the model. Red petal bases is a qualitatively inherited trait controlled by a recessive allele at a single locus. ‘Prairie Sunset’ (first red petal based cultivar) was grown in isolation with solid yellow flowered plants and all seedlings of ‘Prairie Sunset’ were yellow. Segregation in the F₂ generation fit a 3:1 solid yellow:red petal base ratio supporting a single gene recessive allele model. The expression of the intensity of red pigmentation and how far up the corolla it was expressed was variable between the red petal-based genotypes. Ray floret number per inflorescence, ray corolla width, and overall inflorescence width are quantitatively inherited. Three F₁ populations were used to estimate narrow sense heritability using offspring mid-parent regression. Eight diverse F₁ hybrid selections were allowed to open pollinate and their offspring were raised to estimate narrow sense heritability using offspring parent regression. Narrow sense heritability was moderate to high at 0.64, 0.53, and 0.65 using offspring mid-parent regression and 0.41, 0.58, and 0.54 using offspring parent regression for ray floret number per inflorescence, ray corolla width, and overall inflorescence width, respectively. Understanding the inheritance of key character traits in heliopsis is valuable to help breeders strategically and efficiently combine them in new cultivars.