GENETIC SIGNATURES FROM AMPLIFICATION PROFILES CHARACTERIZE DNA MUTATION IN SOMATIC AND RADIATION-INDUCED SPORTS OF CHRYSANTHEMUM

The chrysanthemum (Dendranthema grandiflora Tzvelev.) cultivars 'Dark Charm', 'Salmon Charm', 'Coral Charm' and 'Dark Bronze Charm' are eith er radiation-induced mutants or spontaneous sports of 'Charm' and cons titute a family or series of plants that primarily differ in flower co lor. These cultivars, which were difficult to differentiate geneticall y by DNA amplification fingerprinting (DAF), were easily identified by using arbitrary signatures from amplification profiles (ASAP). Genomi c DNA was first amplified with three standard octamer arbitrary primer s, all of which produced monomorphic profiles. Products from each of t hese DNA fingerprints were subsequently reamplified using four minihai rpin decamer primers. The 12 primer combinations produced signatures c ontaining approximate to 37% polymorphic character loci, which were us ed to estimate genetic relationships between cultivars. Forty-six (32% ) unique amplification products were associated with individual cultiv ars. The number of ASAP polymorphisms detected provided an estimate of the mutation rate in the mutant cultivars, ranging from 0.03% to 1.6% of nucleotide changes within an average of 18 kb of arbitrary amplifi ed DAF sequence. The ASAP technique permits the clear genetic identifi cation of somatic mutants and radiation-induced sports that are geneti cally highly homogeneous and should facilitate marker assisted breedin g and protection of plant breeders rights of varieties or cultivars.