‘Biodiversity’ has become a buzz word in the policies of governments and international agencies alike as concern grows over nature conservation in general and the irreparable loss of species. In the case of the olive tree, there is a serious risk of genetic erosion with the growing tendency to use a shrinking number of varieties.

In my professional career, I had the honour to work during 23 years at the International Olive Council (www.internationaloliveoil.org) as head of the research, development and environment Department. Many projects were carried out in the member countries of this prestigious intergovernmental body.

One of the most important projects, and perhaps the one I am most fond of, was the RESGEN project: a project for the conservation, characterisation, collection and utilisation of olive genetic resources.

Olive trees in the Italian hills

THE RESGEN PROJECT

Francesco Serafini at COP 22 in Morocco

Initially conceived as a joint initiative of the European Union and the International Olive Council to collect, characterise and conserve the genetic biodiversity of the olive tree in the producer countries of the EU, the project was later extended to other countries. A total of 22 countries eventually participated in it: Albania, Algeria, Argentina, Cyprus, Croatia, Egypt, France, Jordan, Greece, Iran, Israel, Italy, Lebanon, Morocco, Montenegro, Portugal, Syria, Slovenia, Spain, Tunisia, Turkey, and Uruguay. This project aimed to preserve the richness of olive genetic variability in national collections and in three international collections by carrying out field surveys to recover germplasm not yet identified and to study this genetic heritage.

FOUR INTERNATIONAL COLLECTIONS

The participating countries multiplied their morphologically characterised varieties and sent them to the international collections. The scope of this project was therefore very ambitious.

Twenty-two reference collections were created in the 22 participating countries, and three international collections, specifically in Cordoba (Spain), Marrakech (Morocco) and Izmir (Turkey). In 2023, the IOC recognised another international collection in San Juan, Argentina.

Today, in view of the evident climate change that our planet is experiencing, the conservation and study of olive biodiversity is a priority and will certainly be one of the keys to tackling the problem.

The World Germplasm Bank of Córdoba

THE IMPORTANCE OF THERMOPERIOD AND PHOTOPERIOD

Identifying specific characteristics that enable the olive tree to resist extreme weather events, temperature variations and diseases will enable farmers to plant more resistant olive varieties in the future. For a plant to develop and, above all, produce, two parameters of paramount importance need to be taken into account:

The World Germplasm Bank of Córdoba

the thermoperiod, that is the annual, daily and aperiodic variation in air temperature; and the photoperiod, that is the set of processes that allow plants to regulate their biological functions using the number of hours of light available during the year. The olive tree is a marvellous plant: it can withstand very dry climates, as is the case with the Tunisian Chemlali variety that forms the Sfax ‘forest’, region where the average rainfall does not exceed 230 mm/year.

The olive tree also withstands cold climates with temperatures as low as -7ºC. This wonderful and unique genetic heritage is therefore an incredible resource.

CONCLUSIONS

Genetic improvement for the establishment of new genotypes able to meet this climatic ‘challenge’ will be one of the most important objectives.

There are more than 2000 known varieties of olive trees that have developed and adapted to the most diverse climates. However, even though 95% of the world production of olive oil and table olives is represented by no more than 150 varieties, the knowledge and study of the genetic heritage of the Olea europaea species offer solutions that will be able to give continuity to olive growing in a future that, we can affirm, is already upon us.

Francesco Serafini worked for 23 years at the IOC as head of the Department of Research Development and Environment. He is currently president of the association “The Garden of Peace” and honorary president of the association “Olivares Monumentales de Andalucía”.

Francesco Serafini at the World Germplasm Bank in Cordova