Submitted to: International Symposium on Human Health Effects of Fruits and Vegetables
Publication Type: Abstract Only
Publication Acceptance Date: 9/1/2005
Publication Date: 9/1/2005
Citation: Farnham, M.W. 2005. A comprehensive program to enhance glucoraphanin content of broccoli heads and seed. Proc Symposium on Human Health Effects of Fruits and Vegetables. 17-20 August 2005. Quebec City, Quebec. P. 30. Interpretive Summary: Interpretive Summary not required for ab Abstract.
Technical Abstract: Broccoli (Brassica oleracea L., Italica Group) is a recognized source of glucosinolates and their isothiocyanate breakdown products. Glucoraphanin is one of the most abundant glucosinolates present in broccoli. Its cognate isothiocyanate is sulforaphane, a potent inducer of mammalian detoxication (Phase 2) enzyme activity. Increasing evidence indicates that sulforaphane in broccoli may confer significant chemoprotection against particular cancers. For the last decade, the USDA-Agricultural Research Service’s cole crops breeding and genetics project at Charleston, South Carolina has conducted a comprehensive program to enhance glucoraphanin levels in broccoli. Initial efforts were aimed at altering levels in the vegetable head, but have now expanded to altering levels in harvested seed. The attention on seed came as a result of reports that broccoli seed contained glucoraphanin concentrations up to ten times greater than those found in the vegetable head. Combined results of numerous studies on broccoli florets lead to conclusions that: genotypes express significant consistency in glucoraphanin levels across environments; selection among genotypes for glucoraphanin level in heads has been successful; biological activity (e.g., phase 2 enzyme induction potential) and glucoraphanin concentration are correlated; and performance of a given parent in hybrid combinations should be predictable (i.e., it should be possible to develop broccoli hybrids with high head glucoraphanin based on knowledge of the parents). Parallel results with seed indicate that genotype is the most significant factor influencing levels of glucoraphanin in this plant part. Importantly, self-compatible broccoli inbreds developed in this research produce consistently high yields of seed that exhibit relatively high glucoraphanin levels. These inbreds are of interest to seed producers wishing to optimize glucoraphanin yield from seed for the production of this glucosinolate or the production of sulforaphane (e.g., its cognate isothiocyanate) as a fine chemical. Overall, results of the ARS effort on broccoli indicate that development of broccoli genotypes that deliver maximum chemoprotective potential in vegetable heads or in seed is feasible.