Development and characterization of polymorphic microsatellite markers for the sweet orange (Citrus sinensis L. Osbeck)

The aims of this study were to develop simple sequence repeat markers (SSRs or microsatellite markers) in citrus and to evaluate the efficiency of these markers for characterization of sweet orange. We developed SSRs from a genomic library of ‘Pêra IAC’ sweet orange enriched for AG/TC, GT/CA, TCA/AGT and AAC/TTG sequence repeats. We selected 279 sequences from which 171 primer pairs were designed of which 113 with the best banding patterns were selected. Characterization of sweet orange microsatellite loci revealed that AG/TC was the most abundant (69%) microsatellite class isolated, followed by GT/CA (15.9%), TCA/AGT (8%) and AAC/TTG (6.2%). The number of alleles ranged from 1 to 4, with a mean of 2 alleles per locus. Four microsatellite loci developed in this study were found to be useful for sweet orange DNA typing. The data obtained from microsatellites loci considered polymorphic will be useful as tools in the selection of zygotic and nucellar plants, identification of seedlings etc. for the cultivars Pêra IAC, Lanceta, Pêra GS 2000, Lamb Summer, Lima, Lima Tardia, Lima Verde, Mimo do Céu, Valência Folha Murcha, Valência Folha Concha, Natal Murcha, Sangüínea and Baía Gigante.