*3.1. Mining Functional Loci/Genes*

Some linked markers and mapped genes/QTLs for desirable traits have been reported, and with the development of sequencing technology in recent years, candidates have been predicted for mapped genes/QTLs. Omics technologies, such as transcriptomics, proteomics and metabolomics, have been employed to understand the mechanism of desirable traits. Despite efforts, quite a few genes in broccoli have been cloned and functionally verified. Further research should focus on mining and functionally verifying more genes/QTLs for guiding and promoting the breeding work of broccoli: (1) As the most desirable traits in broccoli are controlled by complex QTLs, secondary mapping populations, including near-isogenic lines, introgression lines and chromosome segment substitution lines, should be developed for fine mapping and isolation of these genes; (2) by reverse genetics approaches, released databases and advanced sequencing technology can be used to identify more functional genes; and (3) the obtained target genes, neither from fine mapping nor homology cloning, should be verified by transient expression or genetic transformation.
