Genome-wide association study and genomic prediction of white rust resistance in USDA GRIN Spinach Germplasm

White rust, caused by Albugo occidentalis, is one of the major yield-limiting diseases of spinach (Spinacia oleracea) in some major commercial production areas. The use of host resistance is the most economical and environment-friendly approach to manage white rust in spinach production. The objectives of this research were to conduct a genome-wide associating study (GWAS), to identify single nucleotide polymorphism (SNP) markers associated with white rust resistance in spinach, and to perform genomic prediction (GP) to estimate the prediction efficiency (PA). A GWAS panel of 346 USDA germplasm accessions was phenotyped for white rust resistance under field conditions and genotyped with 13,235 SNPs postulated from whole-genome resequencing (WGR). The SNP markers and the high PA can provide valuable information for breeders to improve spinach by marker-assisted selection (MAS) and genomic selection (GS).