GENOMIC AND EST MICROSATELLITE LOCI DEVELOPMENT AND USE IN OLIVE: MOLECULAR TOOLS FOR GENETIC MAPPING AND ASSOCIATION STUDIES

Identification of QTLs (quantitative trait loci) related to agronomic traits based on segregating population and/or on a collection of unrelated genotypes needs the use of molecular markers. Here, we aimed to develop and characterize genomic and expressed sequence tag (EST)-derived microsatellite markers in olive (Olea europaea L.) and assess their Mendelian inheritance on the pseudo-F₁ population derived from the cross ‘Olivière’ × ‘Arbequina’. Based on an enriched genomic DNA library constructed on the French cultivar ‘Olivière’, we designed 211 primer pairs among the total 584 identified SSR loci. Following 454 sequencing of cDNA fragments obtained on the Slovenian cultivar ‘Istrska belica’, we designed 113 primer pairs among 976 identified as EST-SSR loci. We screened these SSR markers for their informativeness for the saturation of the previously published linkage map based on the same cross, designed for bearing regularity study (in Montpellier, France). A set of 59 genomic and 40 expressed SSR loci were selected to genotype the 147 offspring. Twenty four (25.53%) SSRs show a Mendelian distortion segregation at P<0.05. From genotyped SSRs, 85 (90%), 64 (68%) and 94 (100%) SSR loci are now available for completing respectively ‘Olivière’ and ‘Arbequina’, and the integrated maps published earlier.