Analysis of the molecular diversity of Olea europaea in the Mediterranean Island of Malta

Abstract

The island of Malta is a small densely populated land mass located in the middle of the Mediterranean Sea. Genetic material from local olive tree varieties on the island was amplified using RAPD, 36 loci were subsequently generated and a dendrogram based on Jaccard's similarity coefficient constructed. Analysis of clustering patterns indicated a high degree of genetic diversity (0.18-0.68), an early separation between the majority of the native varieties and more recently introduced varieties, supporting the idea of a history of limited genetic exchange and indicating a separate clustering for the majority of the 'Malti' and 'Bidni' varieties. Principal Component Analysis of banding patterns confirmed these clustering patterns and analysis of the incidence of bands for primers OPA-17, OPC-19, OPI-18 (vector correlation significance \0.01) as well as for OPAG-13, OPAN-15 (vector correlation between 0.01 and 0.05) showed strong correlation. Native Maltese varieties were characterised by a higher number of bands arising from the former group of primers indicating their use as a possible means to distinguish between local and imported varieties.

The First Identification of the Uniqueness and Authentication of Maltese Extra Virgin Olive Oil Using 3D-Fluorescence Spectroscopy Coupled with Multi-Way Data Analysis

“…There are three major identified olive cultivars within the Maltese islands which are thought to be native, namely the 'Bidni', 'Bajda' and 'Malti' [21]. Whilst the 'Bidni' and 'Bajda' are monocultivars, the 'Malti' is thought to be made up of several ancient varieties which are geographically isolated from each other [22]. Furthermore, recent studies have shown that Maltese EVOOs have a significantly different phenolic composition and mineral composition [23,24].…”

A First Description of the Phenolic Profile of EVOOs from the Maltese Islands Using SPE and HPLC: Pedo-Climatic Conditions Modulate Genetic Factors

“…DNA based methods are effective in allowing a traceability chain to be established between tree and oil [12]. In a first approach, random amplified polymorphic DNA (RAPD) and microsatellite analysis [11,13] were used to identify marker sequences specific to local varieties. Both studies showed that indigenous olive trees occupied a distinct group.…”

Genetic flow among olive populations within the Mediterranean basin

“…Syria is part of the original habitat of O. europaea , with 90 cultivars identified so far, although only five varieties, that is, Zaity, Sorani, Doebli, Khoderi, and Kaissy, are extensively cultivated ( Al-Ibrahem, Bari & Rashed, 2008 ; Tubeileh, Abdeen & Al-Ibrahem, 2008 ). In the Maltese archipelago, three principal cultivars, namely Bidnija, Maltija, and White olive or Bajda, were identified ( Mazzitelli et al, 2015 ) in addition to the rare wild olives characterized by small shrubs, short leaves, and small, bitter-tasting fruits with low oil content. The Maltija variety is highly productive and it is the most common and widespread cultivar in the islands, while Bidnija (from the Bidnija region) is believed to be one of the oldest olive cultivars, indicating that it may date back from the Roman occupation ( Buhagiar, 2012 ).…”

“…The Maltija variety is highly productive and it is the most common and widespread cultivar in the islands, while Bidnija (from the Bidnija region) is believed to be one of the oldest olive cultivars, indicating that it may date back from the Roman occupation ( Buhagiar, 2012 ). The Bidnija produces oil of excellent quality, is rich in polyphenols and shows high tolerance to environmental stresses such as salinity and drought, and to olive fruit fly ( Mazzitelli et al, 2015 ). “Bajda” produces characteristic white drupes, and it was rediscovered in 2010, as a possible survivor of the famous Maltese “Perlina” or “Pearls of Malta” referenced in Renaissance literature ( Verde, 2017 ).…”