Genotyping analysis demonstrates variable predictive accuracy of downy mildew resistance markers across Brassica genebank accessions, indicating genetic background dependency.
Key Points
To assess whether previously identified SSR markers linked to downy mildew resistance reliably predict resistance phenotypes across diverse Brassica oleracea genebank accessions.
Analyzed 313 individual plants representing 115 Brassica accessions with documented cotyledon-stage resistance phenotypes following Hyaloperonospora parasitica inoculation.
Screened five simple sequence repeat (SSR) markers (CB10028, CB10139, BoGMS0900, BoGMS0486, and BoGMS0624) linked to resistance loci Pp 523, Ppa 207, and Ppa3.
The five SSR markers amplified a total of 29 alleles across the tested accessions.
Marker-phenotype associations were inconsistent across different crop types and accessions, with CB10028 and BoGMS0900 showing the highest informativeness.
Other markers demonstrated strong dependency on genetic background, preventing their use as universal predictors of cotyledon-stage downy mildew resistance without population-specific validation.