Algerian Olive Germplasm and Its Relationships with the Central-Western Mediterranean Varieties Contributes to Clarify Cultivated Olive Diversification

Abstract

Olive tree with its main final product, olive oil, is an important element of Mediterranean history, considered the emblematic fruit of a civilization. Despite its wide diffusion and economic and cultural importance, its evolutionary and phylogenetic history is still difficult to clarify. As part of the Mediterranean basin, Algeria was indicated as a secondary diversification center. However, genetic characterization studies from Maghreb area, are currently underrepresented. In this context, we characterized 119 endemic Algerian accessions by using 12 microsatellite markers with the main goal to evaluate the genetic diversity and population structure. In order to provide new insights about the history of olive diversification events in the Central-Western Mediterranean basin, we included and analyzed a sample of 103 Italian accessions from Sicily and, a set of molecular profiles of cultivars from the Central-Western Mediterranean area. The phylogenetic investigation let us to evaluate genetic relationships among Central-Mediterranean basin olive germplasm, highlight new synonymy cases to support the importance of vegetative propagation in the cultivated olive diffusion and consolidate the hypothesis of more recent admixture events occurrence. This work provided new information about Algerian germplasm biodiversity and contributed to clarify olive diversification process.

Utility of EST-SNP Markers for Improving Management and Use of Olive Genetic Resources: A Case Study at the Worldwide Olive Germplasm Bank of Córdoba

“…These findings likely support that multi-local selection and breeding of olive cultivars occurred in each area of present diffusion, but also reflect a diversification process of cultivated olive from the east to west Mediterranean [ 36 , 53 , 64 , 65 ]. The high level of admixture in the central Mediterranean gene pool and the preferential clustering of many accessions with the eastern Mediterranean cultivars, as well as the clear clustering of western Mediterranean cultivars into an independent gene pool, may permit to envisage various scenarios for the development of olive cultivars in these regions: (a) an east to west dispersal pattern of olive cultivars with human migration [ 36 , 64 , 65 ]; (b) a possible local selection of wild genotypes best adapted to environmental conditions and to agronomic expectations [ 35 , 63 , 66 ]; and (c) a further breeding of cultivars introduced from abroad with local material, either wild and/or cultivated [ 17 , 18 , 39 , 40 , 64 , 67 ]. Local selection specifically adapted to particular environmental conditions can explain some differences between accessions and could be of great interest for olive breeding.…”

Identification and Characterization of Relict Olive Varieties (Olea europaea L.) in the Northwest of the Iberian Peninsula

“…Molecular markers, especially microsatellites (SSR), have been successfully used to identify monumental, ancient native or locally cultivated olive trees throughout the Mediterranean Basin in Algeria [21,22], Montenegro [23,24], Italy [14,25,26], Greece [27,28], Turkey [29,30], the Maltese Islands [31], and Spain [1]. These markers have also proven to be very suitable for germplasm collection management [2,[32][33][34].…”

Revealing the Diversity and Complex Relationships of Croatian Olive Germplasm

“…Complex relationships between olive cultivars and various cases of synonymy revealed by molecular markers have been previously described in numerous studies at the regional [ 16 , 19 , 23 , 45 , 54 ], national [ 13 , 15 , 17 , 18 , 20 , 22 , 47 , 55 , 56 , 57 ], and international levels [ 12 , 23 , 58 ].…”