A Genetic Linkage Map of Olive Based on Amplified Fragment Length Polymorphism, Intersimple Sequence Repeat and Simple Sequence Repeat Markers

Abstract

<jats:p>A detailed genomic linkage map of the olive [<jats:italic>Olea europaea</jats:italic> L. ssp. <jats:italic>europaea</jats:italic> (2<jats:italic>x</jats:italic> = 2<jats:italic>n</jats:italic> = 46)] was constructed with a 147 F1 full-sib ‘Olivière’ <jats:italic>×</jats:italic> ‘Arbequina’ progeny in a two-way pseudo-test cross-mapping configuration. Based on a logarithm of odds threshold of 6 and a maximum recombination fraction of 0.4, maternal and paternal maps were constructed using 222 makers [178 amplified fragment length polymorphism (AFLP), 37 simple sequence repeat (SSR), seven intersimple sequence repeat (ISSR)] and 219 markers (174 AFLP, 39 SSR, 6 ISSR) markers, respectively. The female map regrouped 36 linkage groups (LGs) defining 2210.2 cM of total map length with an average marker spacing 11.2 cM and a maximum gap of 48.5 cM between adjacent markers. The male map contained 31 LGs and covered a distance of 1966.2 cM with an average and a maximum distance between two adjacent markers of 10.3 and 40.4 cM, respectively. Mean LG size was 61.3 and 63.4 cM in the maternal and paternal maps, respectively. The LGs consisted of two to 17 loci (up to 21 loci in the paternal map) and ranged in length from 2.7 to 182 cM (female map) or from 4.1 to 218.1 cM (paternal map). Markers were distributed throughout the maps without any clustering. The total length of the consensus map was 3823.2 cM containing 436 markers distributed into 42 LGs with a mean distance between two adjacent loci of 8.7 cM. Both parental maps and the consensus maps were compared with previously published olive maps. Although not saturated yet, the present maps offer a promising tool for quantitative trait loci mapping because phenotypic characterization of the cross is currently carried out.</jats:p>

Recent developments in olive (Olea europaea L.) genetics and genomics: applications in taxonomy, varietal identification, traceability and breeding

“…Ben Sadok et al (2013) increased the number of markers mapped on the existing Olivière 9 Arbequina map (Khadari et al 2010); the resulting female map consisted of 25 linkage groups covering 1745 cM, while the paternal map consisted of 21 linkage groups covering 1597 cM and the integrated map of 26 linkage groups covering 2148 cM. This map is currently the most saturated map obtained for olive with classic molecular markers.…”

“…Subsequently, Wu et al (2004) used 104 seedlings from the crossing between the cultivars Frantoio (female parent) 9 Kalamata (male parent) to obtain two parental and an integrate linkage map using the pseudo-testcross strategy. Recently, new and interesting results were obtained in this sector; in 2010, two papers reported on the development of linkage maps: Khadari et al (2010), using 147 seedlings of a cross between the cultivars Olivière (female parents) 9 Arbequina (male parents), and El Aabidine et al (2010), using 140 cross progenies from the cultivars Picholine Marocaine (female parent) 9 Picholine du Languedoc (male parent). The first population (Khadari et al 2010) was analysed using more than 400 markers (AFLPs, ISSRs and SSRs) while the second population (El Aabidine et al 2010) was characterised using nearly 600 markers (SSRs, AFLPs, ISSRs, RADs, SCARs).…”

“…Recently, new and interesting results were obtained in this sector; in 2010, two papers reported on the development of linkage maps: Khadari et al (2010), using 147 seedlings of a cross between the cultivars Olivière (female parents) 9 Arbequina (male parents), and El Aabidine et al (2010), using 140 cross progenies from the cultivars Picholine Marocaine (female parent) 9 Picholine du Languedoc (male parent). The first population (Khadari et al 2010) was analysed using more than 400 markers (AFLPs, ISSRs and SSRs) while the second population (El Aabidine et al 2010) was characterised using nearly 600 markers (SSRs, AFLPs, ISSRs, RADs, SCARs). With respect to the first maps, these two maps were obtained using a higher number of markers, making them a more suitable tool for applications such as QTLs detection.…”

“…This map is currently the most saturated map obtained for olive with classic molecular markers. In 2014, Essalouh et al (2014) added new markers, EST (Expressed Sequence Tags) derived SSRs, to further increase the saturation of the map obtained by Khadari et al (2010).…”

“…Usually, the high number of characteristics useful from an agronomic or economic point of view is quantitative traits and controlled by a high number of loci (QTLs) spread in the genome. Ben Sadok et al (2013) identified 12 QTLs on the genetic map based on Olivière 9 Arbequina (Khadari et al 2010), with small effects for interesting traits such as flowering; fruiting and production at whole tree scale. The highest part of QTLs was linked to alleles from the paternal cultivar Arbequina.…”