*2.6. Development of Omics Research*

Advances in techniques and reduced costs of high-throughput next- and third-generation sequencing have brought high-throughput tools for genomic-related studies and the improvement of broccoli. In 2014, *B. oleracea* draft genome-based short reads of the next generation were released [124,125]; in 2018, the first broccoli (HDEM) reference genome, a high-quality daft genome based on third-generation nanopore long reads and optical maps, was accessible [85]. These studies provided information on genome duplication and gene divergence and the direct prediction of genes related to phytochemicals and morphological variations and, as mentioned above, provided a reference for high density marker development [97,116,118]. Bulked-segregant analysis combined with whole genome resequencing (BSA-seq) for rapid gene/QTL mapping and candidate searching [13,32] and omics-related studies exploring differentially expressed genes/miRNAs related to important traits [26–30,121–123]. In addition, high-throughput strategies promote KASP marker-based fingerprinting for the essential

broccoli germplasm [126], genetic diversity and population structure analysis for broccoli cultivars [11,127], and the genomic and morphological domestication syndrome of broccoli calabrese landraces, hybrids and sprouting broccoli [11].
