Development of a maize 55 K SNP array with improved genome coverage for molecular breeding

Area of Science:

• Plant Genomics
• Agricultural Science
• Molecular Breeding

Background:

• Single nucleotide polymorphisms (SNPs) are widely used in genotyping due to their abundance and even distribution.
• High-throughput SNP analysis is crucial for molecular breeding in crops like maize (Zea mays L.).
• Existing SNP arrays may have limitations in genome coverage and performance, especially for diverse germplasm.

Purpose of the Study:

• To develop a high-density maize 55K SNP array with enhanced genome coverage for molecular breeding.
• To evaluate the performance of the new 55K SNP array compared to existing platforms.
• To assess the utility of the 55K array for germplasm evaluation, genetic diversity analysis, and breeding applications.

Main Methods:

• Development of a 55,229 SNP array on the Affymetrix® Axiom® platform.
• Genotyping of 593 diverse inbred maize lines.
• Comparative analysis with the Illumina® MaizeSNP50 BeadChip.
• Population structure and genetic diversity analyses.

Main Results:

• The 55K SNP array exhibits improved genome coverage, including exonic, intronic, and unassigned markers.
• It shows lower missing and heterozygous rates and captures more low-frequency SNPs in tropical maize compared to the MaizeSNP50 array.
• The array effectively resolves heterotic groups and performs fine germplasm fingerprinting.

Conclusions:

• The maize 55K SNP array is a powerful tool for molecular breeding and genetic studies in both tropical and temperate maize.
• It facilitates in-depth analysis of genetic variation, including rare variants in tropical germplasm.
• The array supports germplasm evaluation, marker-assisted breeding, and genome-wide association studies (GWAS).