How can I obtain SNP VCF.gz files from hybrid populations and parental populations generated by the Genotyping-By-Sequencing (GBS) approach in publicly available databases like ERA or others?

I am working on a breeding project using SNP data to map them to specific QTL to construct linkage maps. However, before proceeding, I need to verify if the hybrids are true hybrids. I intend to use publicly available data, but I am unsure how to obtain VCF files. Any help would be highly appreciated.