Abstract
The possibility of identification of onion (Allium cepa L.) cultivars by DNA analysis was investigated. The genetic diversity of twenty onion cultivars from Japan, New Zealand, Australia, the USA and Thailand were examined, and 19 sets of sequence-tagged site (STS) primers were designed. Discriminating bands were amplified by each set of STS primers using DNA extracted from 24 onion bulbs of each cultivar. Individual variations in DNA bands in each cultivar were shown, which caused difficulties in discrimination between cultivars in the case of two sets of STS primers which were designed from cytoplasmic DNA (chloroplastic and mitochondrial DNA). However, some individual variations were shown in each cultivar by using the other seventeen sets of STS primers which were designed based on genomic DNA. These results suggested that the identification of onion cultivars using a single onion bulb is impossible. However, because it was shown that the population of allele frequency derived from each cultivar tended to be constant, it may be possible to identify onion cultivars using a significance test to compare allele frequencies of two populations derived from multiple onion bulbs of two varieties.
