Polymorphic Microsatellite DNA Markers in Opuntia spp. Collections

In the present study, five SSRs from a novel set of microsatellite loci and 8 previously isolated are analyzed in different species and cultivars of Opuntia, selected from two 'on field' collections located in Italy and Argentina. The objectives were to investigate the genetic variability in the cactus pear and assess the ability of the tested SSR markers in identifying and discriminating Opuntia accessions at species and intra-species levels. All SSRs produced polymorphic amplifications in the 29 accessions analyzed. The mean value of the polymorphic index content (PIC) for the SSR loci provided good discriminating ability for the assessment of genetic diversity in the genotypes included in the study. The diversity indices were higher in the species population than in the cultivars populations, but the cultivated accessions retained more diversity than expected for a domesticated species.