Genetic structure and core collection of the World Olive Germplasm Bank of Marrakech: towards the optimised management and use of Mediterranean olive genetic resources

Abstract

The conservation of cultivated plants in ex-situ collections is essential for the optimal management and use of their genetic resources. For the olive tree, two world germplasm banks (OWGB) are presently established, in Córdoba (Spain) and Marrakech (Morocco). This latter was recently founded and includes 561 accessions from 14 Mediterranean countries. Using 12 nuclear microsatellites (SSRs) and three chloroplast DNA markers, this collection was characterised to examine the structure of the genetic diversity and propose a set of olive accessions encompassing the whole Mediterranean allelic diversity range. We identified 505 SSR profiles based on a total of 210 alleles. Based on these markers, the genetic diversity was similar to that of cultivars and wild olives which were previously characterised in another study indicating that OWGB Marrakech is representative of Mediterranean olive germplasm. Using a model-based Bayesian clustering method and principal components analysis, this OWGB was structured into three main gene pools corresponding to eastern, central and western parts of the Mediterranean Basin. We proposed 10 cores of 67 accessions capturing all detected alleles and 10 cores of 58 accessions capturing the 186 alleles observed more than once. In each of the 10 cores, a set of 40 accessions was identical, whereas the remaining accessions were different, indicating the need to include complementary criteria such as phenotypic adaptive and agronomic traits. Our study generated a molecular database for the entire OWGB Marrakech that may be used to optimise a strategy for the management of olive genetic resources and their use for subsequent genetic and genomic olive breeding.Electronic supplementary materialThe online version of this article (doi:10.1007/s10709-011-9608-7) contains supplementary material, which is available to authorized users.

Genetic diversity of on-farm selected olive trees in Moroccan traditional olive orchards

“…These SSR loci were selected on the basis of their clear amplification and high polymorphism observed in previous studies (Sarri et al, 2006;Khadari et al, 2008;Baldoni et al, 2009;Haouane et al, 2011). Six and eight among the 12 SSR loci are distributed throughout six and seven linkage groups, respectively Zine El Aabidine et al, 2010).…”

Testing Different Approaches to Construct an Olive (Olea Europaea L.) Core Subset Suitable for Association Genetic Studies

“…Based on 12 nuclear SSR loci, the analysis of 561 accessions revealed 505 single genotypes with 210 alleles of which 24 alleles were observed only once (Haouane et al, 2011). Sixty four cultivars (12.5%) were necessary to capture all the alleles using the Mmethod and SLS method when optimizing the CV.…”

“…A total of 561 accessions, maintained in the ex-situ world olive germplasm bank at the experimental orchard of Tassaoute, INRA Marrakech, Morocco (WOGB Marrakech), were characterised using 12 nuclear SSR loci (Haouane et al, 2011). Phenotypic data was taken from published data based on the variety name as an identification key (Bartolini et al, 1998;Bartolini, 2008).…”

Transcriptomics and Biochemical Profiling: Current Dynamics in Elucidating the Potential Attributes of Olive

“…Since olive is primarily important vegetable oils source in the world, therefore it is economically significant to understand the philosophy of its plant architecture (Conde et al, 2008). But most of the current cultivars of olives are traditional (Belaj et al, 2012) that are not well acclimatized to the modern patterns of olive cultivation (Haouane et al, 2011). The main focus of modern trends is to promote intensive plantations of 2000 tree per hectare from the traditional 100 tree per hectare in hedge row growing systems (Baptista and Biswas, 2010).…”

“…However, canopy size and shape is adjusted according to high densities by pruning that aims to attain the maximum leaf to wood ratio (Rosati et al, 2013) under least shading (Haouane et al, 2011). These methods are used for the plantations of Spanish varieties like Arbequina and Arbosana in intensive hedgerow orchards owe to their good agronomic potential (Rosati et al, 2013).…”