GENETICS OF ALIPHATIC GLUCOSINOLATES .4. SIDE-CHAIN MODIFICATION IN BRASSICA-OLERACEA

The biochemical and genetical relationship between aliphatic glucosino lates which have methylthioalkyl, methylsulphinylalkyl and alkenyl sid e chains has not been resolved by biochemical studies. In this study, two hypothetical models are tested by the generic analysis of a backcr oss population between Brassica drepanensis and B. atlantica. The resu lts support one of the models in which 3-methylthiopropyI glucosinolat e is sequentially converted to 3-methylsulphinylpropyl, and then to 2- propenyl glucosinolate, by the action of dominant alleles at two loci. RFLP mapping positioned both loci on the same linkage group homologou s to the B. napus N19 linkage group. The implication of the results fo r the genetic manipulation of glucosinolates in Brassica to improve fl avour and nutritional properties, and in order to investigate plant-in sect interactions, is discussed.