Resprouting capacity of Nothofagus obliqua Mirb. (Oerst): genetic and environmental factors

APARICIO, ALEJANDRO; BARBERO, FERNANDO; PASTORINO, MARIO JUAN

Bordeaux

Conferencia; IUFRO Conference “Genetics of Fagaceae and Nothofagaceae”; 2012

INRA

Resprouting capacity is a primary life-history trait of mediterranean plants. We assess the genetic and environmental factors affecting seedling resprouting capacity of Nothofagus obliqua, in two common garden trials: Bariloche (790 m a.s.l.) and Golondrinas (415 m a.s.l.). We used 1920 three-year-old seedlings from 40 open-pollinated families nested in four populations (Epulauquen, Catritre, Pilo-lil and Yuco). Prior to the fourth growing season, we cut the plants at the collar level. We surveyed resprouting using a three-step model, accounting for a) pre-disturbance seedling condition; b) resprouting capacity (RC) and vigour (RV); and c) resprouting survival (RS). Accordingly, we measured pre-disturbance seedling height (Sh), RC (binary), RV (percentage of Sh reached by dominant resprout/s), resprouting profusion (RP: number of dominant shoots) and RS (binary) at the end of the first post-disturbance growing season. In Bariloche (colder site) we also recorded summer frost damage (SFD) (percentage of green tissue damaged by an episodic frost) and shoot apical damage (AD) before dormancy (binary) due to seasonal cold. For variance analyses and hypotheses testing, we used generalised linear mixed models and likelihood ratio test (LRT) approach. RC (94%) and RS (93%) were so high that potential differences between treatments could not be assessed. In both trials RV was associated with pre-disturbance Sh by exponential relationships, which differed only in their decay rates with Sh, suggesting that the shortest plants invested more on root biomass prior to disturbance, and also a site effect on RV. RP was weakly correlated to RV (rS=-0.13, p