Relation between morphology and native climate in the resistance of different Pinus pinaster populations to pitch canker disease caused by Fusarium circinatum

Maritime pine (Pinus pinaster) is a forest species of great ecological and economic interest in the European Union, and especially in the Iberian Peninsula. Currently, one of the main threats this species has to face is the spread of the quarantine pathogenic fungus (A2 list) Fusarium circinatum, causal agent of pine pitch canker disease. Since one of the main strategies for the control of the disease is the use of resistant clones, it is necessary to carry out extensive work on the susceptibility analysis of several P. pinaster populations against F. circinatum. To this end, we have studied 35 P. pinaster populations located throughout the natural distribution range. After inoculation with F. circinatum spores, the susceptibility of all populations was studied, correlating it with their morphological traits (height and stem diameter) and relating it with the climate of origin. The results obtained reported significant differences among populations in both the morphological traits and susceptibility to the disease, with a negative correlation between height and susceptibility. With respect to the climate of origin, a negative correlation between continental climate and resistance was established. Therefore, populations with the indicated characteristics could be selected for the establishment of programs of breeding for resistance to control the spread of F. circinatum in P. pinaster forests.