Skip to main content
ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower Improvement Research » Research » Publications at this Location » Publication #421852
Research Project: Sunflower Yield, Crop Quality, and Interactions with Biotic and Abiotic Stressors

Location: Sunflower Improvement Research

Title: Understanding genetic architecture overcomes tradeoffs between seed quality and insect resistance

Author
item WHITE, JOSEPH - University Of Colorado
item McNellie, James
item KEEPERS, KYLE - University Of Colorado
item SMART, BRIAN - North Dakota State University
item PORTLAS, ZOE - Arundel Metrics (WILL BE EVOLVING INTO DATA MAVEN)
item Prasifka, Jarrad
item KANE, NOLAN - University Of Colorado
item Hulke, Brent

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/23/2025
Publication Date: N/A
Citation: N/A

Interpretive Summary: In sunflowers, the outer portion of a seed is called a pericarp. This portion of the seed keeps insect pests from eating the seeds, but the genes involved in making it stronger or thicker were previously unknown. It is also unknown why oil content of the seeds is reduced with thicker pericarp. In this study, we found the genetic regions in sunflower that correspond to these traits, including insect resistance. We found that thickness, and other traits independent of thickness, are involved with making stronger pericarps. While thickness has this unfortunate correlation with lower oil, the other strength-related traits do not. Therefore, we conclude that it is possible to make sunflowers with high oil, strong pericarps, and increased insect resistance.

Technical Abstract: Crop damage from insect herbivory is a pervasive and persistent problem faced in nearly all crops, including sunflower (Helianthus annuus). The sunflower pericarp protects the seed within from both abiotic and biotic stresses. Achenes with stronger pericarps are less susceptible to damage from insect feeding. Complicating the genetic improvement of pericarp strength is the negative correlation between pericarp thickness (a component of strength) and oil content. As breeding efforts have increased oil content, there has been a concomitant decrease in pericarp thickness. A logical sunflower improvement goal is to improve oil content while preserving pericarp strength through genetic mechanisms independent of pericarp thickness. To determine the genetic basis of oil content, pericarp strength, and thickness, we identified QTL in two populations; the Sunflower Association Mapping panel (Mandel et al., 2011) and a recombinant inbred line (RIL) population derived from a thin pericarp oilseed inbred (HA 467) crossed to a thick pericarp open pollinated variety from Türkiye (PI 170415), mapping QTL for pericarp strength, pericarp thickness, pericarp strength independent of thickness (residual of strength regressed on thickness), banded sunflower moth damage, and oil content. A QTL on chromosome 15 was associated with insect resistance, oil content, and pericarp strength, apparently underlying the trade-offs among these traits. Additional QTL on chromosome 5 and 14 for pericarp hardness provide fewer trade-offs with oil content. QTL for pericarp strength on chromosome 5 and pericarp thickness on chromosome 16 were associated with inversions, with candidate gene presence/absence variation between the haplotypes on chromosome 5. Understanding the origin and nature of phenotypic tradeoffs is beneficial not only to sunflower breeders, but to plant biologists more generally as they seek to understand the origin and genetic architecture of maladaptive traits.