Determining the morphological indices indicating acorn diversity of Persian oak trees at tree and site level

The present study was conducted to determine the morphological indices indicating the diversity of Persian oak acorn in two forest sites on the northern and southern slopes of Ilam forests. In each site, 12 oak trees were selected and from each tree, 100 acorns were collected from the four main crown sides as a composite sample. Samples were transferred to the laboratory to measure the morphological traits of the fruit and its cup. The values of fruit length, fruit diameter, cup length and cup diameter were different among trees in each site. Also, the values of fruit length and fruit diameter were higher in the northern site than the southern site. Plasticity study showed that fruit length and fruit diameter traits have less plasticity. Moreover, the values of fruit length, fruit diameter, cup length and cup diameter were significantly different among tree groups with different degrees of crown dieback. Therefore, it was found that the acorns of Persian oak trees are significantly affected by the individual characteristics of trees, site conditions and the severity of crown dieback. Although variability among trees in terms of site differences and the degree of crown dieback can be due to plasticity, but individual and intra- population changes in fruit traits can be due to their genetic and in this regard, fruit length and fruit diameter traits are morphological indicators indicating the diversity of Persian oak acorn.
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