Morphological evaluation of cork oak (Quercus suber): Mediterranean provenance variability in Tunisia

Abstract

-Twenty-six provenances (2 340 plants) of cork oak (Quercus suber spp.) originating from Portugal, Spain, Italy, Morocco, Algeria, and Tunisia were tested for genetic variation among and within provenances by growth traits. Seven morphometrical characters were measured in 90 plants from each provenance. Analysis of variance showed highly significant differences for all characters. The phenotypic coefficient of differentiation reached 0.24 for the form and 0.22 for height, thus revealing a strong structuring between the provenances. Comparative study of growth among the provenances revealed more vigorous growth and better survival rate for those from Morocco, Spain, and Portugal, which may constitute better materials for afforestation. Furthermore, this variability appeared to be geographically structured and would be mainly genetically controlled, as cork oak provenances were cultivated under the same environmental conditions. Our results should be helpful for guide forest managers in afforestation. Quercus suber / variabilité génétique / reforestation / plantes méditerranéennes

Understanding the importance of intrapopulation functional variability and phenotypic plasticity in Quercus suber

“…The species is found in a high variety of climatic conditions: Annual precipitation ranges from 400 to 2000 mm and annual temperatures from 12 to 20°C (Catalan 2003;Alía et al 2009;Aronson et al 2009). Previous studies in common gardens have shown that cork oak populations present high variation in survival, growth, and leaf traits (Gandour et al 2007;Ramirez-Valiente et al 2009a, b;2010;2014a, b, c). Adaptation to contrasting environmental conditions has been suggested as the main mechanism responsible for the differences observed in functional traits among populations (Ramirez-Valiente et al 2009b, 2010, 2014b.…”

Natural selection on cork oak: allele frequency reveals divergent selection in cork oak populations along a temperature cline

“…Studies on neutral molecular markers have shown a weak effect of neutral evolutionary processes such as genetic drift, founder effects and bottlenecks not derived from strong selection on the population structure of cork oak and few constraints to gene flow among populations (Toumi and Lumaret 1998;Jiménez et al 1999;Ramírez-Valiente et al 2009a). In contrast, significant differences among populations have been reported for a broad set of growth parameters and functional traits (Aranda et al 2005;Gandour et al 2007;Ramírez-Valiente et al 2009a, b) and adaptation to local climate has been viewed as the main factor responsible for such among-population divergence. As a consequence of climate warming, temperatures are expected to increase at least 2^-°C during this century within the cork oak distribution range (IPCC 2007).…”

Factors affecting cork oak growth under dry conditions: local adaptation and contrasting additive genetic variance within populations

“…Although factors affecting seedling survival have been studied in this species, factors affecting other fitness components are currently unknown. Additionally, it is known that cork oak populations differ in survival, growth, and functional traits related to drought stress tolerance (Gandour et al 2007;Ramírez-Valiente et al 2009a;b, 2010a, b), but there is scant knowledge of its intrapopulation genetic diversity, additive genetic variance, and genetic correlations among traits, so the potential for adaptive evolution of the species under a rapidly changing climate remains uncertain.…”