Abstract: Using the clove base of‘Gailiang’garlic as explants the disease resistant garlic somaclonal
variation was screened on MS media containing different levels of the violet leaf spot pathogen culture
crude toxin by means of multi-step in vitro selection method. The bulblets of the resistant line were then
induced with the screened disease resistant variations and their disease resistance was tested on seedlings
growing from the bulblets by foliage spraying of the pathogen culture crude toxin. The results showed that
the pathogen crude toxin inhibited garlic callus induction evidently and the inhibition became stronger
with the increase of pathogen crude toxin concentration. The suitable concentration of pathogen crude
toxin is 30% for disease resistant somaclonal variation selection. The somaclonal variations were selected
by step culture on the MS media with different levels（10%，20%，30%）of pathogen crude toxin. The
resistance test by foliage spray inoculation of the pathogen culture crude toxin showed that the resistant
seedlings from the bulblets possessed stronger resistance to violet leaf spot than the control.

Key words: garlic, violet leaf spot, crude toxin of pathogen, in vitro selection, somaclonal variation