The historical olive cultivar Mehras is represented by 1000-year trees. It grows in Maysar area in Alhashemya (Ajloun, 32.365906N, 35.663445E). A national research team from National Agricultural Research Centre (NARC), the University of Jordan, and Jerash University carried out a collaborative study to sequence the entire 'Mehras' genome applying cutting-edge next-generation sequencing technology. A huge number of SNP mutations were recorded in 'Mehras'; nearly half a million are evident in the genetic coding regions with great influence by altering amino acids. This highlight the uniqueness of its genetic makeup and its implications on the ability of 'Mehras' to adapt to climate change and harsh environments while maintaining a distinctive olive oil quality.
Both the plastid genome (plastome) and the mitochondrial genome (mitogenome) were assembled and compared with major olive cultivars grown around the Mediterranean sea. The results were compiled in two peer-reviewed articles published in a dedicated journal " Mitochondrial DNA Part B":
1. Haddad, N., Migdadi, H., Brake, M., Ayoub, S., Obeidat, W., Abusini, Y., Aburumman, A., Al-Shagour, N., Al-Anasweh, E. and Sadder, M. (2021). Complete chloroplast genome sequence of historical olive (Olea europaea subsp. europaea) cultivar Mehras, in Jordan. Mitochondrial DNA Part B, 6(1), 194-195.
https://doi.org/10.1080/23802359.2020.1860712
2. Sadder, M., Brake, M., Ayoub, S., Abusini, Y., Al-Amad, I., & Haddad, N. (2023). Complete mitochondrial genome sequence of historical olive (Olea europaea Linnaeus 1753 subsp. europaea) cultivar Mehras in Jordan. Mitochondrial DNA Part B, 8(11), 1205-1208.
https://doi.org/10.1080/23802359.2023.2275828
The major finding showed that 'Mehras' is one of the oldest genetic olive genotypes in the Mediterranean region. The reason for choosing the name Mehras instead of Romi is that the cultural heritage, especially in Ajloun, distinguishes between the size of olive trees.
The phylogenetic analysis showed that Mehras was genetically the closest to be a source of origin for the most important cultivated olives in the Mediterranean basin; namely 'Manzanilla' from Spain and 'Frantoio' from Italy. Therefore, 'Mehras' is a genuine ancestor variety, which has survived through the ages.
Mehras' has a high percentage of extractable oil - up to 28%, one of the highest percentages among olive varieties in the world. 'Mehras' oil also boasts a distinctive fatty acid composition, with one of the highest percentages of oleic acid - up to 70% - compared with other varieties, in addition to the sensory properties and its distinctive fruity flavor.
Our findings agrees strongly with archaeological discoveries which proved that the oldest human settlement ever known to contain olive trees was in the Jordanian village of 'Hadib Al Reeh' in Wadi Rum, which dates back to 5400 BC.
The unique genetic heritage of Jordan's ancient olive tree cultivar 'Mehras' was the key to a new effort to add value to locally-produced olive oil. With the support of international partners, Jordan's producers and exporters association has launched a new extra virgin olive oil, "Ateek", produced from the 'Mehras' cultivar. Moreover, 'Mehras' historical olive tree was chosen for coming official Jordanian mail stamps.