Variation of glucosinolate contents among domestic broccoli (Brassica oleracea L. var. italica) accessions

A total of 95 broccoli (Brassica oleracea L. var. italica) accessions were evaluated for the identification of desulfo-glucosinolates and their content variation in the flower head using ultra performance liquid chromatography, to select the potentially functional broccoli breeding lines. The six individual desulfo-glucosinolates, including progoitrin, glucoraphanin, sinigrin, gluconapin, glucobrassicanapin, and glucobrassicin, were commonly identified, based on the chromatogram peak comparison with those of the nine individual glucosinolate standards. The total glucosinolate contents varied from 4.2 to 29.0 μmol·g^-1 DW and the glucoraphanin (1.6 to 13.9 μmol·g^-1 DW) was confirmed as a major constituent in the total glucosinolate profile among the six identified individual glucosinolate species, whereas the progoitrin, which was only detected in 13 accessions, showed accession-specific variation and negative correlation with glucoraphanin content. It was also revealed that the four major glucosinolates, such as glucobrassicanapin, glucoraphanin, glucobrassicin, and gluconapin, affected major content variation and showed higher positive inter-correlation. These results might be used for the selection of potential breeding materials as functional broccoli germplasm through the further evaluation on the stability and reproducibility of glucosinolate profile depending on environmental factors or cultural managements using the selected accessions.