Adaptive responses for seed and leaf phenology in natural populations of sessile oak along an altitudinal gradient

Abstract

We assessed the adaptive potential of seed and leaf phenology in 10 natural populations of sessile oak (Quercus petraea) sampled along two altitudinal transects using common garden experiments. Population differentiation for both phenological traits was observed with high‐altitude populations germinating and flushing later than low altitude ones. However, high genetic variation and heritability values were also maintained within populations, despite slightly decreasing for dates of leaf unfolding with increasing altitude. We suggest that biotic and abiotic fluctuating selection pressures within populations and high gene flow are the main mechanisms maintaining high genetic variation for these fitness related traits. Moreover, changes in selection intensity and/or selection pressures along the altitudinal gradient can explain the reduction in genetic variation observed for leaf phenology. We anticipate that the maintenance of high genetic variation will be a valuable resource for future adaptation of sessile oak populations undergoing an upslope shift caused by climate change.

Evolutionary responses of tree phenology to the combined effects of assortative mating, gene flow and divergent selection

“…Overall, pollen dispersal occurred at a much higher rate than seed dispersal, as indicated by experimental data in many broad-leaved and conifer tree species (Ennos, 1994). Genetic architecture, allelic effects originate from Derory et al (2010), and heritability values stem from Alberto et al (2011). Based on our earlier simulations (Soularue and Kremer, 2012), and in situ and common garden observations (Vitasse et al, 2009a, b), k E was set to 2, meaning that the variance of E values across the landscape is twofold larger than the phenotypic variance of TBB within a given population.…”

“…We assumed that there is no dominance or epistasis as suggested by high heritability values reported for TBB (Alberto et al, 2011). The mean genetic value of the population at generation t, before selection, is G t , whereas that after selection is G s t .…”

“…We assumed that the macroenvironmental value E was distributed along one dimension, here latitudinal gradient, such that all populations at a given latitude had the same E value (see Soularue and Kremer (2012) for further details). These settings for E values mimic the patterns reported in situ for latitudinal gradients of flushing date in trees (Chuine and Cour, 1999;Vitasse et al, 2009a;Alberto et al, 2011). Each population was composed of 500 individuals, this number remaining constant among populations and over successive generations.…”

Common garden experiments in the genomic era: new perspectives and opportunities

“…Local adaptation might be suspected because of the existence of an environmental gradient such as latitude (Toräng et al, 2015) or altitude (Alberto et al, 2011), or because of the existence of several contrasting environments, such as sea and fresh water (DeFaveri and Merilä, 2014). In addition, common garden experiments are also used to study the consequences of local adaptation for conservation (McKay et al, 2001) or even for ecosystem functioning (Bassar et al, 2010).…”

Influence of Sessile Oak Log Characteristics on the Efficiency in Veneer Cutting

“…is located in wide areas across Europe. Its population spreads from the Iberian Peninsula to Norway, going East to Crimea and Caucaz, passing to Minor Asia and reaching North of the Mediterranean Sea (Kremer and Zanetto 1997;Şofletea and Curtu 2007;Alberto et al 2011).…”