Population genetic studies aimed at the genetic resource conservation of forest tree species

The studied species are Aleppo pine (Pinus halepensis Mill.) and Scots pine (Pinus sylvestris L.), analysed by using isozymes as genetic markers. Aleppo pine populations from southern Italy have been studied by integrating genetic data with archaeobotanical analyses carried out on several archaeological sites concerning a chronological range of 30.000 years, showing the presence of Pinus cf. halepensis in Apulia only from 17.000 to 10.000 years BP. On the basis of the obtained results, we can hypothesize its anthropical introduction in Apulian region probably as a consequence of colonization events from the Aegean area in historical times. Scots pine occupies a larger natural range than any other species from the whole Pinaceae family. Because of such a wide geographic spreading, with very different environmental conditions, and because of the long evolutionary history of this pine, a large intraspecific variation is expected to occur. The aim of this research is to study the genetic differentiation between populations representative of the Eurasian natural range of this species. The obtained results highlight the sharp and outstanding differentiation of an Italian population, located in the Emilian Apennine, which is the most differentiated population by far: it is a relict and isolated remnant from glacial and postglacial migrations, and it is even less similar to the studied Italian Alpine populations than the remaining foreign populations. These observations supply evidence of the status of important genetic resource for this small and autochthonous stand, whose differentiation could depend both on its origin from a different glacial refugium and on a different evolutionary history due to its peripheral position with respect to the main range of Scots pine. Some hypotheses on the postglacial recolonization routes followed by this species have been formulated. These results make it possible the drafting of more accurate programmes of genetic resource conservation.