Morphological and pomological variations of Pistacia atlantica Desf. subsp. cabulica and subsp. mutica in Sistan-va-Baluchestan province, Iran.

Background: The genus Pistacia, belonging to the family Anacardiaceae, includes various species that hold ecological, nutritional, and medicinal significance. There is limited information on the morphological and pomological diversity of Pistacia atlantica Desf. subsp. cabulica and subsp. mutica. This study aims to examine this diversity and contribute to the improvement of sustainable use and agricultural practices.

Results: Morphological and pomological variation of 44 female accessions of P. atlantica (20 of subsp. cabulica and 24 of subsp. mutica) grown naturally in Mount Taftan, Sistan-va-Baluchestan, Iran, was assessed. One-way ANOVA (p < 0.05) showed significant differences among the examined genotypes. The coefficient of variation (CV) ranged from 7.60% (kernel thickness) to 167.04% (kernel crispness), with 34 out of 48 traits (70.83%) showing CVs greater than 20%, indicating high variability. The range of leaf-related characters was as follows: leaf length: 87.52-157.80 mm, leaf width: 55.28-121.97 mm, leaflets per leaf: 5-7, petiole length: 25.87-66.91 mm, and petiole diameter: 1.15-2.2 mm. The range of fruit-related characters was as follows: bunchlets per bunch: 10-17, fruit pedicel length: 1.37-7.12 mm, fruit pedicel width: 0.9-1.23 mm, nut length: 5.49-8.23 mm, nut width: 6.19-8.42 mm, nut thickness: 4.39-6.42 mm, and 100-nut weight: 12.36-25.91 g. These variations indicate adaptability and agricultural potential. Most accessions showed moderate growth, intermediate vigor, and branching, optimizing photosynthesis. Leaf and petiole traits vary, reflecting adaptations to environmental conditions. Ripening times span from late September to mid-October, with yield potential mostly intermediate. According to correlation matrix analysis, high positive correlations were found between 100-nut weight and kernel thickness (r = 0.708**), nut length (r = 0.764**), and nut thickness (r = 0.603**), and these correlations are also supported by multiple regression analysis (β = 0.47, β = 0.69, β = 0.31, P < 0.00, respectively). According to principal components analysis, the first three principal components (PC1 = 13.39%, PC2 = 9.30%, and PC3 = 9.25%) represented 31.94% of the total variation. The datasets were evaluated together, and the first 14 accessions were detected, including four accessions of subsp. mutica (No. 23, 5, 11, and 16) and 11 accessions of subsp. cabulica (No. 5, 15, 18, 10, 20, 12, 1, 7, 17, and 13), respectively. The accessions 1 and 7 of subsp. cabulica, though among the first 14, fall outside the 95% confidence ellipse in the scatter plot, indicating that they differ significantly from the others in terms of their traits. This suggests they may possess unique characteristics.

Conclusions: This study highlights the significant morphological and pomological diversity between the P. atlantica subsp. cabulica and subsp. mutica, providing valuable insights for breeding and conservation. The key trait relationships identified through statistical analysis may guide trait selection for better yield and adaptability.