Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 9/23/2003
Publication Date: 9/23/2003
Citation: Abercrombie, J., Farnham, M.W., Rushing, J. 2003. Genetic combining ability of glucoraphanin level and other horticultural traits of broccoli. Hortscience. 38:783-784.
Technical Abstract: Broccoli (Brassica oleracea L., Italica Group) is recognized as a source of glucosinolates and respective isothiocyanate metabolites that may have chemoprotective effects in humans. Glucoraphanin (4-methylsulfinylbutyl glucosinolate; GR) is a predominant glucosinolate of broccoli, and its cognate isothiocyanate is sulforaphane. Sulforaphane has proven to be a potent inducer of phase II detoxification enzymes, and numerous lines of evidence indicate this induction may provide protection against both carcinogens and toxic electrophiles. Little is known about the genetic combining ability and types of genetic variation (i.e., additive vs. dominance) for glucosinolate levels in broccoli. To better elucidate genetic factors known to influence glucoraphanin content, a diallel mating design was employed to estimate general and specific combining abilities for this trait. This design included nine doubled haploid (inbred) parents and all possible crosses (36) among them, excluding reciprocals. The complete diallel was grown in two field experiments employing randomized complete block designs conducted in fall 2001 and spring 2002. Horticultural traits (i.e., head weight) of all entries were assessed in the trials and harvested heads were lyophilized and assayed for GR concentration using a hydrophilic interaction liquid chromatography method on an HPLC. In fall 2001 GR concentration of broccoli heads ranged from 0.83 to 6.00 umole/gdw, and in spring 2002 ranged from 0.26 to 7.82 umole/gdw. In both years, significant general combining ability was observed for GR concentration, as well as for days from transplant to harvest, head weight, and stem diameter. Conversely, no significant specific combining ability was observed for any trait in either year. Results indicate that a given inbred will combine with others to make hybrids with relatively predictable levels of head glucoraphanin and also other important horticultural traits. This should allow identification of inbreds that give relatively high GR levels when hybridized with others.