Testing the potential significance of different scion/rootstock genotype combinations on the ecology of old cultivated olive trees in the southeast Mediterranean area

Abstract

BackgroundA previous multi-locus lineage (MLL) analysis of SSR-microsatellite data of old olive trees in the southeast Mediterranean area had shown the predominance of the Souri cultivar (MLL1) among grafted trees. The MLL analysis had also identified an MLL (MLL7) that was more common among rootstocks than other MLLs. We here present a comparison of the MLL combinations MLL1 (scion)/MLL7 (rootstock) and MLL1/MLL1 in order to investigate the possible influence of rootstock on scion phenotype.ResultsA linear regression analysis demonstrated that the abundance of MLL1/MLL7 trees decreases and of MLL1/MLL1 trees increases along a gradient of increasing aridity. Hypothesizing that grafting on MLL7 provides an advantage under certain conditions, Akaike information criterion (AIC) model selection procedure was used to assess the influence of different environmental conditions on phenotypic characteristics of the fruits and oil of the two MLL combinations. The most parsimonious models indicated differential influences of environmental conditions on parameters of olive oil quality in trees belonging to the MLL1/MLL7 and MLL1/MLL1 combinations, but a similar influence on fruit characteristics and oil content. These results suggest that in certain environments grafting of the local Souri cultivar on MLL7 rootstocks and the MLL1/MLL1 combination result in improved oil quality. The decreasing number of MLL1/MLL7 trees along an aridity gradient suggests that use of this genotype combination in arid sites was not favoured because of sensitivity of MLL7 to drought.ConclusionsOur results thus suggest that MLL1/MLL7 and MLL1/MLL1 combinations were selected by growers in traditional rain-fed cultivation under Mediterranean climate conditions in the southeast Mediterranean area.Electronic supplementary materialThe online version of this article (doi:10.1186/s12898-017-0114-3) contains supplementary material, which is available to authorized users.

On the origins and domestication of the olive: a review and perspectives

“…Olive grafting has been reported since Classical times, particularly in Ancient Greece and Ancient Rome, and is designed to provide productive varieties with more hardy roots (in Pease, 1933). In contrast to other fruit crops, such as grape or apple (Myles et al, 2011;Cornille et al, 2014;Warschefsky et al, 2016), the intentional breeding of rootstocks is poorly documented in olive (Barazani et al, 2014(Barazani et al, , 2017. Barazani et al (2017) recently showed that scion/rootstock genotype combinations are not randomly distributed, suggesting that growers may have selected some combinations in the Levant area, possibly to improve oil quality or drought tolerance.…”

“…In contrast to other fruit crops, such as grape or apple (Myles et al, 2011;Cornille et al, 2014;Warschefsky et al, 2016), the intentional breeding of rootstocks is poorly documented in olive (Barazani et al, 2014(Barazani et al, , 2017. Barazani et al (2017) recently showed that scion/rootstock genotype combinations are not randomly distributed, suggesting that growers may have selected some combinations in the Levant area, possibly to improve oil quality or drought tolerance. Elucidating ancient cultural shifts linked to the beginning of cultivated olive use and breeding is not a straightforward task (e.g.…”

Genetic Resources of Olea europaea L. in the Garda Trentino Olive Groves Revealed by Ancient Trees Genotyping and Parentage Analysis of Drupe Embryos

“…Our results showed evidences of this cultural practice. It is likely that scion/rootstock genotype combinations are not randomly distributed, but selected by the growers to introduce genotypes with improved agronomic features and/or better adapted to the edaphoclimatic conditions, as suggested by [ 70 ]. The slightly genotypic differences found in some cases between the canopy and the basal part of the tree could be due to a real graft among clones of the same cultivar or to somatic point mutations [ 20 , 65 ].…”

Adaptive response to olive cultivation in a generalist parasitic nematode (Meloidogyne javanica)

“…For instance, resistance to M. javanica has been reported in some olive genotypes (Palomares-Rius et al, 2019;Archidona-Yuste et al, 2020b), while crop intensification and grafting practices may have deep consequences on soil nematode communities (e.g. Warschefsky et al, 2016;Ali et al, 2017;Barazani et al, 2017). In the 17 locations here studied, Ali et al (2017) showed a slightly lower phytoparasitic nematode (PPN) richness in cultivated stands than in the wild habitat (mean: 6.0 vs. 6.4 genera/dm 3 ), while, in Finally, our study highlighted an adaptive response in an asexual parasite.…”