Studing of genetic diversity of some Iranian acid lime (Citrus aurantifolia Swingle) genotypes via AFLP marker

Background and objectives: Citrus is one of the most important crops of semi-tropical regions in the world and acid lime (Citrus aurantifolia) constitute a great proportion of this group. Cultivation of limes are common in southern regions of Iran from many years ago and has an important role in the economy of this region. A large number of limes in these regions were affected and destroyed by many resons and knowledge about genetic of this plants for desining of breeding programs to find suitable plant is helpful. Therefore, in this survey, the genetic diversity of some acid lime genotypes were identified in major cultivation regions of this crop in south of Iran with comparison by six commercial cultivars.
Materials and methods: After selecting young and well expanded leaves, their genomic DNA were extracted. AFLP method was done by using four primer combinations of EcoRI and MseI including ECGC/MAGA, ECCA/MAGA, ECCA/MAGT and ECGC/MAAG. Genetic relationship between 30 local genotypes from three regions Darab (Fars), Manoojan (Kerman), Minaab (Hormozgan) and six foreign cultivars were considered. Collected data was analysed by Jacard similarity coefficient and UPGMA algorithm.
Results: The four combinations produced 126 scorable bands that had %70.63 polymorphism. Number of amplified bands for each primer combination were 26 to 37 (with average of 22 bands for each primer combination). The maximum number of polymorphic bands was observed 27 in ECCA-MAGT combination. Polymorphic information content (PIC) was measured 0.4 to 0.5 for all combinations with an average of 0.48. Similarity range obtained by Jacard similarity coefficient was observed 0.24 to 0.96. Minimum similarity was found between Sweet lime (Citrus limetta) and D8 genotype from Darab and maximum similarity was between two genotypes of Minaab region (M4-2 and M4-2). Cluster analysis arranged samples in four groups that this grouping was not consistent with studied regions. In other words, samples were not separated on basis of collection regions but samples of Minaab region had been shown high level genetic similarity with each other in comparison with samples of Manoojan and Darab regions. This is due to imitated cultivated citrus varieties in the region.
Conclusion: Significant polymorphic percent and polymorphic information content (PIC) obtained from primer combinations used in this study showed ability of these markers to identify different genotypes of acid lime. By using these markers remarkable genetic diversity between genotypes of acid lime were found. But this diversity was not such that could make the difference between genotypes of various locations. It seems that this separation could be achieved by increasing the number of primer combinations and using other markers such as SSR and SNP. Also, results of this study showed that Iranian acid lime genotypes have high level of genetic diversity because they were propagated sexually.