2.1 Cultivated Biodiversity in the Olive Grove

The olive grove is undergoing a period of change. From the traditional rainfed olive grove, with low density and productivity, numerous local varieties and manual harvesting, there is a transition underway towards new high-density, irrigated plantations with a small number of increasingly universalised varieties. Genetic erosion and the vulnerability associated with the reduction in cultivated varieties, the incidence of devastating epidemic pests and diseases such as those caused by Verticillium dahliae and Xylella fastidiosa, as well as forecasts related to climate change have triggered great interest in conserving the cultivated biodiversity of the olive tree. Germplasm banks are collections of olive trees of varieties from a given geographical area. The objective of the Network of Germplasm Banks of the International Olive Council is the conservation, cataloguing, evaluation and free exchange of native cultivated varieties, representative of the selected biodiversity in olive-growing countries.

The Network was established in 1994. It currently includes 26 banks in IOC member countries, of which eight – namely Spain, Italy, Morocco, Türkiye, Argentina, Israel, Iran and Greece (the latter currently in the process of recognition) – have been recognised as international for hosting native cultivars representative of the cultivated diversity in olive-producing countries. The World Olive Germplasm Bank of Córdoba was recognised as the Network’s international reference bank through the signing of an agreement between the IOC, the Ministry of Agriculture and Fisheries of the Regional Government of Andalusia, the Institute for Agricultural, Fisheries, Food and Organic Production Research and Training of the Regional Government of Andalusia (IFAPA, by its Spanish acronym), and the University of Córdoba (UCO) in 2014.
In 2000, the IOC published a first Catalogue describing 139 varieties from 23 olive-growing countries, in accordance with a morphological protocol that served to define the UPOV (International Union for the Protection of New Varieties of Plants) descriptors, which are currently used as the basis for the registration of new protected olive varieties.

In 2016, the IOC agreed to promote the exchange of authenticated and healthy material among the Network’s banks through the True Healthy Olive Cultivars (THOC) transfer project. This project was coordinated by the IOC and UCO, with the participation of the managers of the Network’s banks and other experts invited by the IOC. Its aim was to promote the international certification of nursery plants in member countries, in accordance with their respective legislation. This is an essential service to olive growers in member countries at a time when plantations are increasingly being established with plants from commercial nurseries.

The IOC Network has grown continuously since its creation. It currently includes more than 1,800 varieties in 26 banks in IOC member countries, of which eight (Spain, Italy, Morocco, Türkiye, Argentina, Israel, Iran and Greece) have been recognised as international, due to the presence of native cultivars representative of the cultivated diversity in olive-producing countries worldwide. The Córdoba Bank currently holds the largest number of accessions in the Network, consisting of authenticated, evaluated, sanitised and documented varieties. It is the result of ongoing cooperation between the current IFAPA and UCO since 1970. The role of this Bank has been fundamental since the Network was established.
The present online Catalogue, the second of the IOC Network, includes the main commercial olive varieties propagated by nurseries. These are part of the 181 varieties selected through an IOC survey on the main varieties and those that are the subject of Protected Designations of Origin or Geographical Indications for olive oil and table olives in member countries.
Its content includes:

Varieties and map, focused on the authentication of varieties through a common protocol that includes the UPOV morphological descriptors and molecular markers (SSRs and SNPs) to address the widespread confusion in olive varietal denominations around the world. To this end, a varietal denomination index will establish the proposed reference names and record synonyms, homonyms, errors and molecular variants not expressed morphologically found among the described varieties. The results will be shown on a map. This index will be updated periodically.

Variability – Phenotyping information on agronomic and technical oil-related traits relevant to evaluating varietal behaviour in olive plantations. This information comes from evaluations published by Network banks or from other referenced scientific and technical publications.

The future – Agronomic and biotechnological perspectives on the conservation and use of olive genetic resources. The third phase of the Network will involve the progressive establishment of a new Permanent IOC–FAO Network of Germplasm Banks, based on agreements between the Food and Agriculture Organisation (FAO) and the governments of its member countries, within the framework of the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA). The specific IOC–FAO agreement, together with those signed between the Treaty’s member countries and the FAO, will entail the authentication and sanitation of accessions, the free exchange of this material among the Banks, access to the corresponding databases, and the consolidation of a permanent global infrastructure of genetic resources within the Network.

Currently, two countries — Spain and Morocco — have already incorporated their Olive Germplasm Banks into the Treaty. This Network will also make it possible to establish comparative trials with the most widely planted varieties, to guide varietal selection in the different olive-growing geographies of today and anticipate the behaviour of olive trees in new environments associated with climate change.
In conclusion, an exciting new phase is opening for the conservation, cataloguing, evaluation and sustainable use of olive genetic resources.