Phenotypic and genetic variation of vulnerability to cavitation reveal a potential to adaptation to drought: two study cases in Patagonia

MARTINEZ-MEIER A; DALLA SALDA G; SERGENT AS; FERNÁNDEZ M.E.; ROZENBERG P; MONDINO V; APARICIO A.

Orleans

Conferencia; Wood formation and tree adaptation to climate; 2018

Le Studium-INRA

If weconsider that drought is the main cause of the recently observed forest productivityloss, we should prioritize the study of traits allowing trees to maintain theirhydraulic integrity. Recent studies explored the genetic variation of wood traitsstrongly related to vulnerability to cavitation. They contrast populationscovering a large part of the wide environmental variations to which many ofthese species are exposed. While the absence of significant differences betweenpopulations implies a lack of local adaptation, a large within population variation reveals a certain potential of adaptation.Investigation of within population variation provides information about the possibleexistence of additive genetic variation. Additive genetic variation is the portionof the variation that can really be transmitted from generation to generationand that allows evolutionary adaptation. In the case of natural populations ofcordilleran cypress (an endemic species of Patagonia) a high within populationphenotypic variation of vulnerability to cavitation was found. In Douglas-fir, somevariables of the vulnerability to cavitation curves such as the P50 were found tobe highly genetically determined. The high level of phenotypic and geneticvariability available makes possible the identification and the selection ofgenotypes with desirable hydraulic properties, allowing them to cope withdrought. Such genotypes should be used in breeding programs to create moreresistant to drought varieties.