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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 #430901

Research Project: Evaluation of Sunflower Experimental Germplasm to Identify and Characterize Novel Sources of Resistance to Sclerotinia Head and Stalk Rot

Location: Sunflower and Plant Biology Research

Project Number: 3060-21220-031-17-S
Project Type: Non-Assistance Cooperative Agreement

Start Date: Aug 1, 2016
End Date: Jul 31, 2021

Objective:
The overall objective of this project is to improve genetic resistance of sunflower for two major diseases, head rot and stalk rot, caused by the fungal pathogen Sclerotinia sclerotiorum. The project seeks to (1) Identify novel, broad-spectrum sources of Sclerotinia resistance in cultivated sunflower germplasm and interspecific hybrids of Helianthus annuus with wild relative species, (2) map genetic loci contributing to stalk and head rot resistance by phenotyping structured mapping populations, and (3) Introduce new sources of stalk and head rot resistance by conventional breeding and marker-assisted selection into elite USDA oilseed or confection sunflower germplasm for release to the public. Specific goals for this project period are to: (1) Conduct the second year of evaluation of an advanced backcross mapping population for resistance to Sclerotinia head rot (388 total rows) in an inoculated, mist-irrigated disease nursery; (2) Evaluate testcross hybrids and advanced breeding materials for basal stalk rot (~700 rows) 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; (3) Conduct the second year of evaluations for early generation germplasm from interspecific crosses to identify new lines with superior resistance to basal stalk rot (~ 120 rows).

Approach:
To facilitate project objectives, we will establish inoculated disease nurseries for both stalk and head rot to evaluate: (1) Interspecific hybrids of H. annuus with wild sunflower species at various stages of backcrossing; (2) Structured mapping populations from crosses of resistant cultivated H. annuus or resistant interspecific hybrids for mapping of genomic regions contributing to resistance to facilitate marker-assisted selection; (3) Advanced breeding program materials to confirm improved resistance and collect phenotyping data to facilitate development of genomic selection models; These evaluations must be done at research sites having irrigation facilities and Central Lakes College is one of the closest such sites.