Relevance of marginal populations for breeding and conservation strategies in Patagonian Cypress

PASTORINO, MARIO JUAN; SÁ, MERCEDES; GALLO, LEONARDO ARIEL

Brisbane

Congreso; XXII IUFRO World Congress; 2005

IUFRO

Austrocedrus chilensis is the forest tree species that most penetrates into Patagonian steppe, even surpassig the ecotonal line in sites with mean annual precipitation below 600 mm. Most marginal populations have been ignored till present because of their reduced size (patches of some 100 trees) and their poor forestry phenotypes. The aim of the present study is to evaluate their genetic resources in comparison with those of wetter conspicuous forests. Seeds of 310 trees from 11 marginal populations from the whole Argentinian range of the species were collected. Individuals were genotyped at 12 isozyme loci by subjecting at least six endosperms to horizontal starch gel electrophoresis. Intrapopulation variation was characterized through several classic parameters, which showed that marginal populations are more variable than non-marginal ones (data of a previous study). In order to test adaptive characters as well, a germination trial was carried out in a greenhouse. Seeds from 194 progenies from the harvested populations were sown in a randomized complete block design, with three repetitions. The germination capacity and energy resulted high (73% and 34% respectively) in comparison to those reported for non-marginal populations. At the light of these results, it seems evident that marginal populations from the steppe harbour valuable genetic resources of Patagonian Cypress.