Development and variability analysis of microsatellite markers in peach

A genomic DNA library enriched with AG/CT repeats has been developed from the peach cultivar 'Merrill O' Henry'. The enrichment method was efficient, with 61% of the clones obtained carrying a microsatellite sequence and a yield of one polymorphic microsatellite every 2,17 sequenced clones. From 35 microsatellites detected, 24 were polymorphic in a set of 25 cultivars including 14 peaches and 11 nectarines. A total of 82 alleles were found with the polymorphic microsatellites, with an average of a 37% of observed heterozygosity. Microsatellites with a high number of repeats were generally those having the largest number of aleles. All cultivars except two ('Spring Lady' and 'Queencrest') could be individually distinguished with the markers used, Just three selected microsatellites were enough for the discrimination of 24 out of the 25 possible genotypes. Cluster analysis grouped all nectarines in a single cluster. Peaches, with 75 of the 82 alleles found, were more variable than nectarines, with only 64. Microsatellites appear to be powerful and suitable markers for application in peach genetics and breeding.