Objective To explore the induced effects of colchicine in different concentration and times on Foeniculum vulgare polyploidy.Methods Seed germination rate and mutation rate,morphology of radicle induced mutants,chromosome number,tissue structure,and content and component of essential oil,which induced by colchicine in different concentiation and times were investigaled using the method of soaking seeds.Results The results showed that 0.13% of colchicine concentration and 24 h inducing time had the best induction on F.vulgare polyploidy.Compared to the control,the radicle of mutant was thicker,the chromosome number increased clearly,and the cell number in radicle manifolded distinctly.Among the four main components of essential oil,the contents of Dill apiol in anamorphosis radicle was a little lower than that of the control,but the contents of limonene,(E)-anethole,and camphene in anamorphosis radicle were all remarkably higher than that of the control after induced by colchicine.ConclusionThe content of main essential oil components in fennel mutant induced by colchicine is remarkably enhanced.The study provides the theoretical basis for the breeding of F.vulgare new varieties of high oil content.