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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower Improvement Research » Research » Publications at this Location » Publication #435657
Research Project: Improvement of Sclerotinia Disease Resistance and Management

Location: Sunflower Improvement Research

Title: Parallel mapping of Sclerotinia basal stalk rot resistance and oxalic acid tolerance in sunflower.

Author
item ZAMAN, ISRAT - North Dakota State University
item ANGIDI, SRUSHTIDEEP - North Dakota State University
item PASCHE, JULIE - North Dakota State University
item DEL RIO MENDOZA, LIUS - North Dakota State University
item Underwood, William

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/1/2026
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Sclerotinia basal stalk rot (BSR) of sunflower (Helianthus annuus L.), caused by the necrotrophic fungal pathogen Sclerotinia sclerotiorum, causes significant yield losses in the U.S. Management of this disease is challenging because resistance to BSR is quantitative and no complete resistance has been identified. The fungus produces oxalic acid (OA), a key virulence factor, and tolerance to OA has been suggested as a potential indicator of resistance to BSR. Treatment of sunflower roots with OA mimics BSR symptoms, suggesting OA may contribute to disease development. Additionally, some sunflower lines with strong resistance to BSR exhibit tolerance to OA. However, whether OA tolerance contributes to BSR resistance remains unknown. To examine this relationship, a recombinant inbred line population derived from a cross between a BSR-resistant and OA-tolerant line and a BSR-susceptible and OA-sensitive line was evaluated for both BSR and OA responses. Preliminary BSR phenotyping of the population showed a mean response of 14.2 days to plant mortality and transgressive segregation consistent with quantitative resistance, whereas OA tolerance of the same population had a mean of 20.04 days to mortality. No significant correlation was detected between BSR resistance and OA tolerance, suggesting that OA tolerance does not meaningfully contribute to stalk rot resistance in this population. Quantitative trait locus mapping for both traits is ongoing. This study will identify loci governing BSR resistance and clarify whether OA tolerance plays a role in resistance to this disease.