Environmental and serotiny data of Pinus halepensis

Many plants undergo adaptation to fire. Yet, as global change is increasing fire frequency worldwide, our understanding of the genetics of adaptation to fire is still limited. We studied the genetic basis of serotiny (the ability to disseminate seed exclusively after fire) in the widespread, pioneer Mediterranean conifer Pinus halepensis Mill., by linking individual variation in serotiny presence and level to fire frequency and to genetic polymorphism in natural populations.
After filtering steps, 885 Single Nucleotide Polymorphisms (SNPs) out of 8,000 SNPs used for genotyping were implemented to perform an in situ association study between genotypes and serotiny presence and level. To identify serotiny-associated loci, we performed random forest analyses of the effect of SNPs on serotiny levels, while controlling for tree size, frequency of wildfires, and background environmental parameters.
Serotiny showed a bimodal distribution, with serotinous trees more frequent in populations exp..., Overall, 10 populations of P. halepensis were selected according to two fire modalities, half located in areas that were fire-free from 1959 until 2018 (“No-Fire” modality populations, PHNF) and the other half in areas having suffered at least one fire (“Fire” modality populations, PHF) during the same time period. The pairs “Fire” - “No-Fire” were located between 5 and 25 kilometers apart in order to minimize genetic divergence caused solely by drift (Lotterhos & Whitlock, 2015). The populations were sampled in sites where the past land use was the same in order to mitigate the impact of soil conditions on trait variation (See Romero & Ganteaume 2020). In the current work, the sampling occurred in recent forests (as opposed to ancient forests that could have already been mapped in the 18th–19th centuries), mostly resulting from land abandonment that can provide adequate conditions for regeneration in the absence of fire. In each population, 19 to 20 mature and dominant trees, b...,