Genetic diversity in the endangered Sicilian endemic Brassica rupestris: Proposals for a conservation strategy

Brassica rupestris Raf. is a chasmophyte species that includes two subspecies both endemic to Central-Western Sicily (Italy). ISSR were used to detect the genetic diversity within and among eight populations representative of the species’ distribution range. High levels of genetic diversity were revealed both at population (PPB = 53.88%, HS = 0.212, Sh = 0.309) and species level (PPB = 96.55%, HT = 0.307, Sh = 0.464). The correlation between genetic and geographical distances was negative (Mantel test, r = -0.06 P<0.95). The two subspecies of B. rupestris showed remarkable genetic similarity and molecular data did not definitely support their distinctness. The pattern of genetic variation revealed by our study bears important consequences for conservation management: it is desirable that B. rupestris populations would be preserved in situ with a “dynamic” strategy, while, ex situ conservation programmes might be improved in order to maximize the safeguard of genetic diversity.