Fifty‐eight mature Persian walnut ( Juglans regia ) seedlings growing at six sites in the mountainous regions of Taft, in central Iran, were evaluated to determine their morphological variation and to identify promising individuals. The traits investigated included phenological characteristics, such as budbreak and nut maturity time, and nut characteristics, such as nut and kernel weight, kernel ratio, and shell thickness. Yield efficiency and fruit‐bearing habit were also investigated. The average fruit characteristics: nut weight, kernel weight, kernel ratio, and shell thickness were in the range of 6.0–15.2 g, 2.6–9.1 g, 38.4–79.6%, and 0.4–1.4 mm, respectively. The promising genotypes were AA ₃₃ , AA ₃₅ , AA ₁₁₅ , AA ₁₁₆ , and BA ₁₅₀ . These trees had larger nuts (AA ₁₁₆ ), heavier nuts (15.2 g, AA ₃₃ ), heavier kernels (9.1 g, AA ₃₃ and AA ₁₁₅ ), higher kernel ratio (79.6%, AA ₃₅ ), and later budbreak (BA ₁₅₀ ). A few significant correlations were found between nut weight and nut length (0.57), nut width (0.68), nut thickness (0.67), kernel weight (0.75), and shell thickness (0.32); whereas a negative correlation was detected between shell thickness and kernel ratio (‐0.34). The data correlation matrix was subjected to principal component analysis, a technique that reduced the dimensionality of the data set and revealed the dominating variables. Cluster analysis of the selected genotypes detected three cluster groups. However, no significant relationship was found between morphological diversity and site geography. The promising selected genotypes identified in central Iran will be further exploited by walnut breeding programmes for their tree and nut characteristics.

Pistachio is considered a potential crop for many semi-arid regions affected by salinisation. We examined the effects of salinity on growth of 3 pistachio rootstocks: Badami-e-zarand, Sarakhs, and Ghazvini. Rootstocks were grown in soil in 8-L polyethylene pots and irrigated every 3 days with treatments of 0, 75, 150, or 225 mm NaCl. We measured above-ground biomass, allocation of C to root systems and foliage, and carbon isotope discrimination (?) and proline accumulation after 30 days and again after 60 days. Relative growth rate (RGR) decreased with time for all treatments and rootstocks. RGR and net assimilation rates (NARw) decreased with increasing salinity. In all rootstocks, NARw, but not leaf weight ratio (LWR), was significantly correlated with RGR, indicating that NARw was an important factor underlying growth responses among rootstocks. Increased salinity did not affect leaf water potential (?leaf), even though proline concentrations increased with increasing NaCl concentration, particularly in the Ghazvini rootstocks. Both Cl– and Na+ concentrations in leaves increased from 30 to 60 days but not in roots and stems. The Sarakhs rootstocks accumulated more of Cl– and Na+ compared with other rootstocks. K+ concentration in the roots and stems of all rootstocks also decreased with increasing salinity at both 30 and 60 days. Concentrations of Ca2+ in stems and root systems, but not in leaves, were also reduced by increased salinity in all rootstocks but only after 60 days. Carbon isotope discrimination (?) decreased with increased salinity in the leaves, stems, and roots; however, there was no significant difference in carbon isotope discrimination among rootstocks. We conclude that the Ghazvini rootstock was the most salt tolerant among the rootstocks tested. Carbon isotope discrimination in pistachio rootstocks may be a useful indicator of cumulative salinity history of the plant but is not a suitable indicator for pre-screening of pistachio rootstocks for salinity resistance.

Pollen grains of 11 Iranian apricot ( Prunus armeniaca ) cultivars were examined, using scanning electron microscopy (SEM). Pollen was collected in the 2002 growing season from mature apricot trees grown in The Apricot Collection Orchard, Ismailabad Horticultural Research Station, Qazvin, Iran. For SEM evaluation, pollen grains were observed and photographed at 1000× for whole grain and at 10 000× for sectioning of exine pattern (surface topography). The length (L) and the width (W) of grain, L/W ratio, distance between two furrows and the width of ridges in elliptical pollen, and the base, the altitude and the width of grain and ridges in triangular pollen were measured. Substantial variability in the size, shape, and exine patterns among pollen grains was clearly distinguished. The apricot cultivars were easily separated into two groups according to their pollen grain shapes: (1) elliptical trizonocolpate (five cultivars); and (2) obtuse‐triangular (six cultivars). The pollen grains of all studied apricot cultivars were medium in size: 51.32 × 25.51 μm (length × width) for the elliptical shape, and for the triangular shapes: 39.03 × 31.22 μm (base × altitude). The resultant data from the two types of pollen shapes were analysed using completely randomised design (CRD) with unequal replications. Moreover, multivariate statistical analysis was carried out to distinguish morphometric information from measured parameters of the two pollen grain shapes. The projections of the loadings defined by the first two principal components allowed for the visualisation of the position of apricot cultivars, demonstrating between‐cultivar‐pollen shape variations. Hence, the differences in both exine pattern and surface topography, in particular ridges and pore characteristics, can potentially be used as a diagnostic tool to aid in the identification of apricot cultivars.