The invention relates to a method for producing Brassica oleracea with elevated anticarcinogenic glucosinolate derivatives. The elevated levels are obtained by crossing wild Brassica oleracea species with Brassica oleracea breeding lines, and subsequently selecting hybrids with levels of 4 -methylsulfinylbutyl and/or 3-methylsulfinylpropyl glucosinolates elevated above that initially found in Brassica oleracea breeding lines. The invention also relates to edible Brassica plants, such as broccoli plants, with elevated levels of 4-methylaulfinylbutyl glucosinolate and/or 3 -methylsulfinylpropyl glucosinolates, and to seeds of such plants.