2.1. Non-Mediterranean olive breeding (South America (Uruguay), Iran, China)

North Hemisphere:

In the late 20th century, when the Iranian government decided to expand the country’s olive cultivation area, researchers prioritised the study of the olive tree’s genetic resources. Surprisingly, they found high diversity levels among Iranian olive ecotypes which were clearly distinct from the Mediterranean olive population. Such noticeable diversity, in addition to the identification of promising ecotypes, paved the way for the implementation of programmes for the improvement and breeding of olive trees. Furthermore, through enhanded access to new DNA sequencing facilities thanks to, an Iranian-Chinese collaboration, all Iranian ecotypes have now been fully sequenced. This has led to adoption of a new approach for selecting suitable parents and shortening the screening and breeding process by combining molecular markers (SSR and SNPs) with morphological and pomological data.

Olea cuspidata, a wild olive tree species located in southeast Iran and expanding towards Pakistan, India and China, is now a major focus of a joint olive breeding programme between Iran and China. The aim is to cross wild and local olives to introduce promising new varieties that are better adapted to climate change. Identifying and producing cultivars suitable for growing olives in steep, drought-prone areas as well as in colder regions could significantly expand the area under olive cultivation in both Iran and China.

Furthermore, breeding programmes in these two countries also focus on identifying and producing varieties resistant to harsh climatic conditions. With climate change, the risk of new and unknown olive pests and diseases is expected to increase. Therefore, conserving and expanding genetic resources, using other Olea subspecies to enrich these resources, and developing crossbreeding programmes will form a crucial part of the joint projects between Iran and China. 

In the United States, due to the lack of local olive varieties, farmers mainly use Mediterranean olive cultivars that are better adaptable to the American climate. In recent years, olive breeding in the United States has increasingly focused on developing cultivars with improved disease resistance and drought tolerance. Overall, breeding efforts in Iran, China and the United States have contributed to the development of new and improved olive cultivars that are adapted to local conditions and better meet the needs of growers and consumers. Advances in olive breeding technologies, particularly those based on new genomic approaches, are likely to accelerate innovation in this field in the coming years.

South Hemisphere:

The American continent was the first region outside the Mediterranean where cultivated olive plants (Olea europaea L. subsp. europaea) were introduced in the mid-sixteenth century. The southern region of America, particularly Peru, Argentina, Chile, Uruguay, Brazil, and Colombia, has proven suitable for olive crop development.

Plants introduced to the continent mainly originated from areas near the port of Seville, Spain. For three centuries, olive trees cloned from these original introductions were successfully cultivated, especially along the west coast of South America bordering the Pacific Ocean. Similar genotypes expanded in Peru and Chile, primarily used for table olive production.

However, there have been no significant genetic or molecular characterisation or breeding programmes in either Peru or Chile. Some specimens from these countries have been characterised at the World Olive Germplasm Bank in Córdoba (Spain), where synonyms with other known genotypes have been detected. Nevertheless, there has been no systematic prospection, characterisation, or evaluation of these genotypes. A similar situation applies to olive trees planted in small areas of Colombia.

In Argentina and Uruguay, from the mid-20th century, prospecting, characterisation, improvement and evaluation programmes began to be developed. These efforts involved clonal selection of genotypes and crosses of promising materials in Germplasm Banks belonging to the International Olive Council (IOC) network, using morphological and molecular methodologies for cultivar identification.

One of the most widely cultivated varieties in Argentina is Arauco, characterised through morphological traits and molecular markers (SSR and SNP), and considered one of the most important olive cultivars worldwide.

In Uruguay, clonal selection programmes and evaluations of genotypes introduced in the 19th century (1800s) have been carried out. In recent years, olive trees in Uruguay have been further characterised by morphological analysis and molecular markers (SSR and SNP), revealing synonyms with minor Spanish and Italian varieties, and identifying 11 adapted ecotypes not previously present in international reference collections. These ecotypes are currently undergoing field agronomic evaluation.

In Brazil, at the beginning of the 21st century, prospecting and breeding programmes were initiated. Several synonyms and some "new genotypes" have been detected, although these have not yet been certified according to the protocols of the International Olive Germplasm Banks.

In Southern Africa, the indigenous wild olive Olea europaea subsp. africana occurs widely. In the early 20th century, this wild olive was used as a rootstock for commercial olive tree propagation. Its wide adaptability suggests it could serve as a valuable source of rootstock material for future breeding programmes.

Another autochthonous species, the dune olive (Olea exasperata), is found only in isolated locations along the Western Cape coastal area. This species also holds potential for the development of low-vigour genotypes adapted to saline conditions.

No native olive cultivars are grown commercially in Southern Africa, although seedlings of cultivated olives occur sporadically, sometimes hybridised with indigenous species. Research programmes are underway to identify improved genotypes for cultivars and rootstocks, through evaluation of imported selections and locally developed seedling populations.

In Australia, only introduced olive varieties are grown, and no native genotypes or clonal selections have been detected. A national collection is maintained at the University of Adelaide's Roseworthy campus, where genotypes have been evaluated agronomically and molecularly using RAPD markers.