Location: Sunflower and Plant Biology Research
Project Number: 3060-21220-034-006-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2021
End Date: Jul 31, 2022
This project will contribute to genetic improvement of sunflower resistance to three major diseases that limit sunflower production in the north central US growing region. The project will: (1) Evaluate interspecific hybrids of cultivated sunflower (Helianthus annuus) and related wild Helianthus species for resistance to Sclerotinia basal stalk rot and Phomopsis stem canker in field nurseries to identify new sources of resistance derived from crop wild relatives; (2) Evaluate an advanced backcross genetic mapping population for Sclerotinia head rot resistance over multiple years in inoculated field nurseries to facilitate mapping of disease resistance quantitative trait loci (QTL) introgressed from the wild sunflower species Helianthus nuttallii; (3) Develop new sunflower germplasm resources with novel and/or improved Sclerotinia and Phomopsis resistance in agronomically acceptable germplasm for release to the public.
Inoculated disease nurseries will be established annually to evaluate experimental sunflower materials for resistance to Sclerotinia basal stalk rot and head rot. Basal stalk rot nurseries will be planted in plots with pivot irrigation and plants will be inoculated with Sclerotinia sclerotiorum-infested millet seed deposited in furrows next to plant rows. Inoculated plants will be scored for disease at the end of the growing season. Head rot nurseries will be planted in plots with overhead mist irrigation and plants will be inoculated by spraying with a Sclerotinia sclerotiorum ascospore suspension during bloom. Inoculated plants will be scored for disease prior to plant maturity. Phomopsis stem canker nurseries will be planted adjacent to basal stalk rot plots with pivot irrigation and will rely on natural disease pressure that is generally high at this location. Plants will be scored for stem canker lesions at the end of the growing season. These disease evaluations must be conducted at research sites with irrigation facilities.