Variación geográfica en peso de semilla en poblaciones naturales argentinas de “Ciprés de la Cordillera”

PASTORINO, MARIO JUAN; GALLO, LEONARDO ARIEL

BOSQUE (VALDIVIA)

Universidad Austral de Chile

Lugar: Valdivia; Año: 2000 vol. 21 p. 95 - 109

0304-8799

‘Ciprés de la Cordillera’ is the most important conifer of the Patagonian Andean Forest in Argentina. Geographic variation in seed weight and germination capacity in 11 natural populations distributed in three latitudinal transects and corresponding to the three principal forest types in which this species occurs in Argentina, is studied. Mean weight of 1000 undamaged, filled seeds was 3.94 g and mean germination capacity in nursery trial without cold-humid pretreatment was 12.95 %. Variability was proved for both variables between populations within forest types, and between families within populations. However no significant differences could be proved between forest types (precipitation regions). Most of the total variation was found to be caused by variation between families (85 %). With a complementary analysis variability was proved for seed weight according to the latitud of the populations (at least in dry and mesic environments), and on the contrary it was not possible to prove it between populations within a certain latitud. Ecotypic variation is assumed, which might be explained through adaptive processes to high definite ‘gene flow corridors’, and the additional effect of genetic drift.