Key message The studied populations of Persian oak (Quercus brantii Lindl.) showed high phenotypic variation that is very necessary for the planning, design, and implementation of genetic protection programs for oaks. Abstract Persian oak (Quercus brantii Lindl.) the most important tree species in the Zagros region includes more than 50% of the forests in this region. In the present study, 53 morphological traits were used to evaluate phenotypic variation among 100 trees belonging to Q. brantii collected from 10 areas of Kohgiluyeh-va-Boyerahmad province, Iran. Considerable variability was exhibited among the trees collected based on the traits measured (ANOVA, P < 0.01). The coefficient of variation (CV) ranged from 12.73 (in nut diameter) to 76.06% (in the transparency of leaf upper color). Leaf margin was highly variable, including doubly serrate, serrate, broadly spiny, spiny, and narrowly spiny. Leaf blade length ranged from 59.41 to 122.53 mm, nut weight ranged from 1.39 to 17.24 g, and kernel weight varied from 0.63 to 13.09 g. Principal component analysis (PCA) showed 15 main components, which contributed 76.60% of the total variance. Cluster analysis based on Ward’s method showed two different major clusters among all the trees studied. Besides, the studied 10 populations were placed into four groups in the bi-plot generated with PCA of population analysis. The studied populations of Q. brantii showed high phenotypic variation that is very necessary for the planning, design, and implementation of genetic protection programs for oaks.
