Using cross-country datasets for association mapping in Arachis hypogaea L

Area of Science:

• Agricultural Science
• Plant Breeding
• Genetics

Background:

• Groundnut (Arachis hypogaea L.) is a vital climate-resilient oil crop in sub-Saharan Africa.
• Significant yield gaps exist due to soil fertility issues, low input use, and biotic/abiotic stresses.
• Cross-country evaluation of breeding lines is crucial for accelerating varietal development.

Purpose of the Study:

• To characterize key groundnut testing environments in Uganda and Malawi.
• To identify genotypes exhibiting stable and superior yields for potential release.
• To analyze population structure and identify marker-trait associations for yield-related traits.

Main Methods:

• Phenotypic data collected for 192 groundnut breeding lines across four locations.
• Genotypic data acquired using skim-sequencing.
• Statistical analyses performed to assess genotype x environment interactions and identify marker-trait associations.

Main Results:

• Significant genotypic variation observed for days to flowering, pod yield, shelling percentage, 100-seed weight, and grain yield.
• Nakabango, Chitedze, and Serere formed a mega-environment, with five genotypes (ICGV-SM 01709, ICGV-SM 15575, ICGV-SM 90704, ICGV-SM 15576, ICGV-SM 03710) showing superior stability.
• Population structure analysis revealed three distinct genotype groups; eight and four marker-trait associations were found for days to flowering and pod yield, respectively.

Conclusions:

• Identified promising groundnut genotypes with stable yields in specific African environments.
• Marker-trait associations provide insights for marker-assisted selection in breeding programs.
• Further studies are needed to confirm genotype stability across seasons and characterize candidate genes for trait improvement.