Construction of a Genetic Linkage Map for the Olive Based on AFLP and SSR Markers

Genetic mapping is essential for quantitative trait locus (QTL) identification related to interesting traits. However, only two genetic maps on olive have yet been published, with very few transferable markers. We have constructed a linkage map of the olive according to a “two-way pseudo-testcross” mapping strategy and based on the progeny generated from a cross between ‘Picholine marocaine’ (female parent) × ‘Picholine du Languedoc’ (male parent) cultivars. A total of 592 markers (47 simple sequence repeat [SSR], 509 amplified fragment length polymorphism [AFLP], 27 inter-simple sequence repeat [ISSR], eight random amplified polymorphic DNA [RAPD], and one sequence characterized amplified region [SCAR] marker) were scored in 140 F1 progeny. Linkage groups were defined at a likelihood odds ratio score of 6.00 and a recombination fraction of 0.40. The maternal map consisted of 175 markers clustered into 40 linkage groups and spanning 1547.40 cM, while the paternal map was based on 170 markers clustered into 38 linkage groups and covering 1428.00 cM. For the consensus map, 345 markers were used covering 2366.4 cM and clustered into 49 linkage groups with a mean distance between two adjacent loci of 8.06 cM and the estimated map coverage of 72.6%. This integrated map provides a useful tool for the detection of QTLs controlling economically important traits.