Field heritability of a plant adaptation to fire in heterogeneous landscapes

• Published in: Molecular ecology Vol. 24; no. 22; pp. 5633 - 5642
• Main Authors: Castellanos, M. C, González‐Martínez, S. C, Pausas, J. G
• Format: Journal Article
• Language: English
• Published: England Blackwell Scientific Publications 01-11-2015; Blackwell Publishing Ltd; Wiley
• Subjects: Adaptation, Physiological - genetics; animal models; Bayes Theorem; climatic factors; cone serotiny; DNA, Plant - genetics; ecosystems; fire regime; Fires; fruits; genetic traits; genetic variance; Genetic Variation; Genetics, Population; Genotype; heritability; landscapes; Life Sciences; Models, Genetic; natural selection; Phenotype; phenotypic variation; Pinus - genetics; Pinus halepensis; Pinus pinaster; plant adaptation; Polymorphism, Single Nucleotide; Quantitative genetics; seeds; Selection, Genetic; Sequence Analysis, DNA; single nucleotide polymorphism; SNP-based relatedness; Spain; spatial variation; Spain; Pinus pinaster; SNP-based relatedness; cone serotiny; Pinus halepensis
• ISSN: 0962-1083; 1365-294X
• DOI: 10.1111/mec.13421

The strong association observed between fire regimes and variation in plant adaptations to fire suggests a rapid response to fire as an agent of selection. It also suggests that fire‐related traits are heritable, a precondition for evolutionary change. One example is serotiny, the accumulation of seeds in unopened fruits or cones until the next fire, an important strategy for plant population persistence in fire‐prone ecosystems. Here, we evaluate the potential of this trait to respond to natural selection in its natural setting. For this, we use a SNP marker approach to estimate genetic variance and heritability of serotiny directly in the field for two Mediterranean pine species. Study populations were large and heterogeneous in climatic conditions and fire regime. We first estimated the realized relatedness among trees from genotypes, and then partitioned the phenotypic variance in serotiny using Bayesian animal models that incorporated environmental predictors. As expected, field heritability was smaller (around 0.10 for both species) than previous estimates under common garden conditions (0.20). An estimate on a subset of stands with more homogeneous environmental conditions was not different from that in the complete set of stands, suggesting that our models correctly captured the environmental variation at the spatial scale of the study. Our results highlight the importance of measuring quantitative genetic parameters in natural populations, where environmental heterogeneity is a critical aspect. The heritability of serotiny, although not high, combined with high phenotypic variance within populations, confirms the potential of this fire‐related trait for evolutionary change in the wild.