The 2012 ASHS Annual Conference

Isothiocynates derived from glucosinolates in brassica vegetables have been reported to induce quinone reductase activity, an important cancer chemopreventative biomarker. Methyl jasmonate (MeJA) has been shown to increase glucosinolates and reduce insect damage in broccoli. For these reasons we have conducted several studies to determine application protocols that maximize glucosinolate accumulation in broccoli florets. We investigated the effect of varying MeJA application concentrations (0, 62.5, 125, 250, and 500 µM), number, and application date in days prior to harvest of broccoli florets of the cultivar ‘Green Magic’. A single application of 250 µM of MeJA maximized glucosinolate concentration in broccoli florets. Two days of consecutive treatments of 250 µM MeJA further increased total glucosinolate concentrations (primarily gluconasturtiin and neoglucobrassicin) four days prior to harvest. In addition to glucosinolate levels the flavonoids, quercetin and keampferol, were observed to show significant increases when 62.5 µM MeJA was applied four days prior to harvest. These application protocols were found to maximize glucosinolate concentrations and putatively enhance the health promoting properties of broccoli florets.