Registration of Oilseed Sunflower Germplasms RHA 461, RHA 462, RHA 463, HA 465, HA 466, HA 467, and RHA 468 with Diversity in Sclerotinia Resistance, Yield, and Other Traits

Sclerotinia head and stalk rots are among the most devastating diseases in sunflower (Helianthus annuus L.). Breeding for resistance to these diseases while maintaining or improving yield and quality is complicated by the quantitative inheritance of the resistance, for which there are few genes of major effect. The objective of this work was to provide new diversity to sunflower breeding organizations for yield and Sclerotinia resistance, together with other useful agronomic and end user traits. Four restorer germplasms, RHA 461 (Reg. No. GP-337, PI 655012), RHA 462 (Reg. No. GP-338; PI 655013), RHA 463 (Reg. No. GP-339; PI 655014), and RHA 468 (Reg. No. GP-341; PI 667184), and three maintainer germplasms, HA 465 (Reg. No. GP-342; PI 670488), HA 466 (Reg. No. GP-340; PI 667183), and HA 467 (Reg. No. GP-343; PI 670489) were developed by the USDA-ARS and the North Dakota Agricultural Experiment Station, Fargo, ND. Testcrosses with these germplasms had yield similar to high-yielding commercial checks and Sclerotinia resistance similar to the highly resistant check Northrup King 277'. Some of the lines also have high oleic acid in the seed oil, downy mildew resistance, and tolerance to imidazolinone herbicides. The lines are available for sunflower breeders to integrate into their breeding programs for additional diversity.