Nothofagus pumilio and N. antarctica: the most widely distributed and cold tolerant southern beeches in Patagonia

Abstract

Nothofagus pumilio and N. antarctica are main components of the Andean Patagonian Temperate forests that occur along all the environmental gradients that characterize the Patagonian region. In this chapter, their main botanical features and natural ranges are presented, as well as the state-of-the-art in genetic studies. Phylogeographic patterns based on chloroplast DNA help inferring Pleistocene refugia location and colonization pathways. Both species share haplotypes and interspecific hybridization occurs naturally. A genetic structure analysis through genomic microsatellites shows latitudinal trends, species admixture and contact zones. Selective logging evidences an effect on patterns of genetic diversity in N. pumilio. The definition of genetic zones contributes to the conservation and management of the genetic resources of both species. In addition, quantitative genetic variation and phenotypic plasticity are analyzed under nursery and field conditions, in juvenile morphological, phenological, physiological and growth rhythms traits. Ecotypic variation was detected along longitudinal and altitudinal gradients of N. pumilio. Finally, the domestication and development of low intensity breeding strategies are presented, including a provenance trial network and seed production areas of N. pumilio, and progeny seed orchards of N. antarctica.