An Investigation of genetic diversity of some hawthorn genotypes using morphological characterization of leaf and fruit

Background and objectives: 
Hawthorn is a forest fruit tree which is grown in the temperate regions around the world. This plant is known as the most traditional herbal remedy for heart failure and cardiovascular disease in worldwide. This study has been conducted to investigate the genetic variability and classify hawthorn genotypes based on quantitative and qualitative characteristics of leaf and fruit. In addition, the identification of desirable genotypes based on investigation of different characteristics from botany and horticultural perspective can be used for germplasm preservation and breeding programs of this crop.
Materials and methods:
In this study, genetic variation among thirty hawthorn genotypes belonging to four species was evaluated based on seventeen morphological characters of leaf and fruit. These accessions were collected from different geographical sites in north and west of Iran. Leaf and friuts samples were collected randomly from various parts of trees at normal fully mature of each accession. In order to evaluate of traits related to leaf, thirty leaves were selected randomly from each genotype with three replications and the characters of them were recorded. To investigate the traits related to fruit, ten fruits were chosen randomly from each genotype with three replications and the characters of them were recorded.
 
Results: Preliminary results illustrated that some traits such as fruit weight, leaf area, and leaf length, depth of leaf sinus, seed length and petiole length have shown high variability among accessions. Results derived from cluster analysis, divided the genotypes into two main groups which pontica and microphylla species were separated from others species including monogyna and pentagyna. Simple correlation analysis among traits showed that positive correlations were detected among them. Factor analysis showed that 85% of total variance was indicated by five main factors. Two first factors were related to leaf and fruit characteristics, constructed 55% of the total variance.  In PCA, leaf area, petiole length and number of leaf in the node simultaneously characters releted to seed and fruit such as seed weight, seed length, fruit dry matter and fruit moisture content were predominant in the first components, indicating that they were useful for the assessment of hawthorn genotypes characterization.
Conclusion:
Finally, the results of this study showed that there is high variability among hawthorn genotypes in terms of quantity and quality characteristics of fruit. Also, the fruit weight significantly varies among hawthorn accessions, and some genotypes which belong to pontica species had quite high weight. Therefore, these species can be used to be cultivated commercially or to be utilized in breeding program to achieve desirable progeny.