Characterization and transferability of microsatellite markers of the cultivated peanut (Arachis hypogaea)

Thirteen loci were isolated and characterized using 16 accessions of A. hypogaea. The level of variation found in A. hypogaea using microsatellites was higher than with other markers. Cross-transferability of the markers was also high. Sequencing of the fragments amplified using the primer pair Ah11 from 17 wild Arachis species showed that almost all wild species had similar repeated sequence to the one observed in A. hypogaea. Sequence data suggested that there is no correlation between taxonomic relationship of a wild species to A. hypogaea and the number of repeats found in its microsatellite loci.These results show that microsatellite primer pairs from A. hypogaea have multiple uses. A higher level of variation among A. hypogaea accessions can be detected using microsatellite markers in comparison to other markers, such as RFLP, RAPD and AFLP. The microsatellite primers of A. hypogaea showed a very high rate of transferability to other species of the genus. These primer pairs provide important tools to evaluate the genetic variability and to assess the mating system in Arachis species.The origin and the diversity center of the genus Arachis are in South America [1]. This genus comprises 69 species, most of which are diploid and wild. The cultivated species include A. hypogaea L., the cultivated peanut, A. glabrata and A. pintoi, which have been used in forage production [2,3]. This genus is divided into nine sections (Arachis, Erectoides, Heteranthae, Caulorrhizae, Rhizomatosae, Extranervosae, Triseminatae, Procumbentes and Trierectoides) according to their morphology, geographic distribution and sexual compatibility [1].The extensive morphological variation in A. hypogaea has led to the identification of subspecies, although studies using molecular markers have found little polymorphism in the germplasm of this species [4-6]. The observed restriction in genetic variation limits the use of several approaches, such as molecular marker-assisted selection and the c