Article

The study of genetic diversity, based on allele frequency has allowed to select the Sicilian wild populations of Brassica deserving conservation priority. The measurement of allele richness and the prcsence of local alleles have been used in order to describe genetic variation patterns belonging to different hierarchicallevels. The allele structure at subspecies level contributes to the total genetic diversity, the absolute contribution of a single population decreases with the increase of the number of sampled populations. Planning conservation at section level is of great advantage as regards conservation at subspecies level and can form the basis for the realization of the core collection. In order to preserve 37 all eles found in the Sicilian populations studied, priority has been given to al B. rupestris subsp hispida (Borgetto) and of B. incana (Gonato) popùlations for their allele richness b) B. macrocarpa population for the presence of the rare and local all ele 5 at locus Lap-l. c) B. incana (Longi) e B. villosa subsp bivoniana (Caltabellotta) for the presence of common and widely distributed alleles not captured in the populations already described in a and b. The survi val percentage ofthe seedlings of B. macrocarpa in nature is very low, this fact doesn 't allow the fruiting planls to produce a population able to maintain and preserve genetic diversity, for this reason ex situ conservation and reintroduction in the native habitat is advisable. The evaluation and monitoring of the quality of the accessions before and during the storage period, in order to maintain a collection of vigorous individuals, assume the knowledge of germination ecophysiology and of the germination testing before storage in the seed bank.