Abstract Seeds of rapid-cycling Brassica oleracea were mutagenized with the chemical mutagen, ethylmethane sulfonate. The reverse genetics technique, TILLING, was used on a sample population of 1,000 plants, to determine the mutation proWle. The spectrum and frequency of mutations induced by ethylmethane sulfonate was similar to that seen in other diploid species such as Arabidopsis thaliana. These data indicate that the mutagenesis was eVective and demonstrate that TILLING represents an eYcient reverse genetic technique in B. oleracea that will become more valuable as increasing genomic sequence data become available for this species. The extensive duplication in the B. oleracea genome is believed to result in the genetic redundancy that has been important for the evolution of morphological diversity seen in today's B. oleracea crops (broccoli, Brussels sprouts, cauliXower, cabbage, kale and kohlrabi). However, our forward genetic screens identiWed 120 mutants in which some aspect of development was aVected. Some of these lines have been characterized genetically and in the majority of these, the mutant trait segregates as a recessive allele aVecting a single locus. One dominant mutation (curly leaves) and one semi-dominant mutation (dwarf-like) were also identiWed. Allelism tests of two groups of mutants (glossy and dwarf) revealed that for some loci, multiple independent alleles have been identiWed. These data indicate that, despite genetic redundancy, mutation of many individual loci in B. oleracea results in distinct phenotypes
