Six pairs of twins were found in the progeny of an aneuploid (2n=67) in Brassica napus L. var. oleifera DC. The frequency of occurrence of twins was 9.09%. Five pairs had chromosomes between 60 and 68 inclusive. These were presumably of sexual origin. One pair, both members of which had 40 chromosomes, probably originated from the cleavage of a reduced unfertilized cell which developed parthenogenetically.
