High genetic diversity detected in olives beyond the boundaries of the Mediterranean Sea.
BACKGROUND
Olive trees (Olea europaea subsp. europaea var. europaea) naturally grow in areas spanning the Mediterranean basin and towards the East, including the Middle East. In the Iranian plateau, the presence of olives has been documented since very ancient times, though the early history of the crop in this area is shrouded in uncertainty.


METHODS
The varieties presently cultivated in Iran and trees of an unknown cultivation status, surviving under extreme climate and soil conditions, were sampled from different provinces and compared with a set of Mediterranean cultivars. All samples were analyzed using SSR and chloroplast markers to establish the relationships between Iranian olives and Mediterranean varieties, to shed light on the origins of Iranian olives and to verify their contribution to the development of the current global olive variation.


RESULTS
Iranian cultivars and ecotypes, when analyzed using SSR markers, clustered separately from Mediterranean cultivars and showed a high number of private alleles, on the contrary, they shared the same single chlorotype with the most widespread varieties cultivated in the Mediterranean.


CONCLUSIONS
We hypothesized that Iranian and Mediterranean olive trees may have had a common origin from a unique center in the Near East region, possibly including the western Iranian area. The present pattern of variation may have derived from different environmental conditions, distinct levels and selection criteria, and divergent breeding opportunities found by Mediterranean and Iranian olives.These unexpected findings emphasize the importance of studying the Iranian olive germplasm as a promising but endangered source of variation.
National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
Mehdi
M
Hosseini-Mazinani
CNR - Institute of Biosciences and Bioresources, Perugia, Italy.
Roberto
R
Mariotti
National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
Bahareh
B
Torkzaban
National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
Massoma
M
Sheikh-Hassani
National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
Saeedeh
S
Ataei
CNR - Institute of Biosciences and Bioresources, Perugia, Italy.
Nicolò G M
NG
Cultrera
CNR - Institute of Biosciences and Bioresources, Perugia, Italy.
Saverio
S
Pandolfi
CNR - Institute of Biosciences and Bioresources, Perugia, Italy.
Luciana
L
Baldoni
D000483:Alleles; D002736:Chloroplasts / Q000235:genetics*; D017753:Ecosystem; D005819:Genetic Markers; D014644:Genetic Variation; D007492:Iran; D008522:Mediterranean Sea; D031658:Olea / Q000235:genetics*
D005819:Genetic Markers