Dissecting the genetic architecture of sunflower disc diameter using genome-wide association study

Area of Science:

• Plant genetics
• Agricultural science
• Crop improvement

Background:

• Sunflower (Helianthus annuus L.) is a vital global source of edible oil.
• Seed yield in sunflowers is influenced by various component traits, including disc diameter.
• Understanding the genetic basis of disc diameter is key to enhancing sunflower oil yield.

Purpose of the Study:

• To assess phenotypic variation in sunflower disc diameter over multiple years.
• To estimate the heritability of the disc diameter trait.
• To identify genetic loci and candidate genes associated with sunflower disc diameter using genome-wide association studies (GWAS).

Main Methods:

• Phenotypic data collection for disc diameter from 342 sunflower accessions over three years (2019, 2020, 2022).
• Genotyping of 274 accessions using tunable genotyping-by-sequencing (tGBS), generating 226,779 single nucleotide polymorphisms (SNPs).
• Genome-wide association study (GWAS) employing mixed linear model (MLM) and fixed and random model circulating probability unification (farmCPU) approaches.

Main Results:

• Broad-sense heritability (H²) for disc diameter was estimated at 0.88.
• GWAS identified 106 significant SNPs (MLM) and 8 significant SNPs (farmCPU) associated with disc diameter.
• Significant signals were detected on chromosomes 10 and 16, implicating specific genetic loci and candidate genes.

Conclusions:

• Sunflower disc diameter is a highly heritable trait.
• Identified genetic loci and candidate genes provide a foundation for marker-assisted selection and breeding strategies.
• This research offers potential for improving sunflower oil yield through genetic enhancement of disc diameter.