No abstract

The pinewood nematode, Bursaphelenchus xylophilus, originating from North America (NA), is a major invasive pine pest in Eurasia. It was first detected in Portugal in 1999 associated with maritime pine, Pinus pinaster, and has been differently affecting the main local pine species, P. pinaster and P. pinea. Field studies and direct inoculation experiments in Pinus spp. seedlings, under controlled conditions, were performed to assess whether the differences in constitutive and inducible defences are determining the different susceptibility of pine host species to B. xylophilus. Host co-evolution with the pathogen was also assessed, including the NA P. radiata, widely used in forestry in the northeast of the Iberian peninsula. Pine mortality in the field was positively related with the abundance of B. xylophilus, and concentration of phenolics and condensed tannins in pines. In the greenhouse assay, seedling tissues were analysed for constitutive investment in defences, as well as the potential inducibility of those defences as driven by B. xylophilus inoculation. Slower growing P. pinea presented higher levels of constitutive defences than faster growing P. pinaster, with only P. pinaster being affected by B. xylophilus. Furthermore, co-evolution with the pathogen is important, with the fast-growing NA P. radiata presenting an inducible and effective response to B. xylophilus. Results point to the importance of integrating data on pine life history traits, including growth rate, and production of constitutive and inducible defences, into predictive models for this invasive forest pest.

Hybridization footprint suggests introgression with local wild relatives in Western European grape varieties.

Cork oak (Quercus suber L.) has a high ecological and social value and supplies raw materials for the cork industry, a relevant contributor to the economies of Mediterranean countries. Understanding the adaptation potential of cork oak populations to cope with different environmental conditions is a key issue of forest management, particularly for selecting the most adapted genetic material for (re)forestation and assuring the long-term sustainability of the cork industry. Intraspecific variation in fitness surrogate traits (survival, height and stem diameter) was investigated in thirty-five cork oak populations sampled from the entire range of the natural distribution of the species. The study was conducted in two provenance field trials, established in Portugal under different edaphoclimatic conditions. Each trial was surveyed at four tree ages (two ages, 11 and 14 years, were sampled simultaneously in both trials). The trial located at a lower altitude, which had higher mean winter and annual temperatures, exhibited higher growth and survival rates. In both trials, significant genetic variation among cork oak populations was observed for the analyzed traits and evaluated ages. Moroccan populations displayed a higher probability of survival and higher growth rates, while local populations exhibited an intermediate performance. Low to moderate correlations were found between the analyzed traits and the environmental variables of seed origin, suggesting that factors other than climate are likely to be relevant for cork oak adaptation. Moderate to high values of population mean-basis broad-sense heritability (H 2 ≥ 0.44) and high genetic correlations between traits (0.88-0.95) were found for growth traits. This information is crucial for the establishment of a breeding program for the species. With this study, we have improved the knowledge regarding how cork oak performs for fitness surrogate traits in different environments.