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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Research Project #437104

Research Project: Field Evaluation of Sclerotinia Head and Stalk Rot of Sunflower for Genetic Mapping and Germplasm Development

Location: Sunflower and Plant Biology Research

Project Number: 3060-21220-031-26-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Aug 1, 2019
End Date: Jul 31, 2021

The overall objective of this project is to facilitate genetic improvement of sunflower for Sclerotinia stalk and head rot through genetic mapping and germplasm characterization. Specific objectives for the 2020 project period are to: 1. Conduct the second year of multi-year, multi-location field evaluations of an advanced backcross mapping population for Sclerotinia head rot resistance to facilitate genetic mapping efforts. 2. Conduct the second year of evaluations for early generation germplasm lines derived from interspecific crosses to identify new lines with superior resistance to basal stalk rot. 3. Evaluate testcross hybrids and advanced germplasm lines for basal stalk rot to determine performance of new, potentially resistant inbred lines when utilized for hybrid production, to evaluate newly developed lines for prospective public release, and to collect data for development of genomic selection models.

Field phenotyping for both head rot and stalk rot resistance will be performed on sunflower research materials. In 2019, we will establish an inoculated, mist-irrigated head rot nursery at Carrington, ND as well as an inoculated stalk rot nursery at Carrington. The head rot nursery will be inoculated with a suspension of Sclerotinia ascospores at 20% bloom to establish disease and evaluated for head rot approximately 6 weeks after inoculation. The stalk rot nursery will be inoculated with Sclerotinia-infested millet approximately 6 weeks after planting and evaluated for disease at plant maturity. This project, in addition to developing cultivated sunflower germplasm with improved Sclerotinia resistance, also involves identifying Sclerotinia resistance in wild annual and perennial Helianthus species and interspecific hybrids between these species and cultivated Helianthus annuus to increase diversity in sources of resistance to Sclerotinia diseases. Additionally, advanced backcross mapping populations derived from crosses of cultivated H. annuus with wild sunflower species possessing Sclerotinia resistance will be phenotyped to facilitate genetic mapping. The personnel on this project are responsible for maintaining the research plots, setting up the mist irrigation system for head rot screening, and assisting with inoculation for head rot screening of a diverse group of wild interspecific and cultivated sunflower germplasm lines.