Molecular Characterization and Genetic Diversity of Citrus aurantium L. Germplasm from Central Italy

A set of six microsatellite primers pair developed in Citrus reticulata were used to evaluate genetic diversity of 19 Citrus aurantium L. (sour orange) accessions from the Umbria Region of Central Italy. Transferability of microsatellite markers was tested on samples of C. aurantium L. and C. sinensis. Primer cross amplification was 91%. The unweighted pair group method with arithmetic mean (UPGMA) analysis based on the Lynch's band coefficient (1990) and the probability of identity (PI), calculated for each locus, and for increasing locus combination, revealed the high power of the microsatellite markers for an unambiguous characterization of the three Citrus species. A high genetic similarity level (between 1.0 and 0.8) was detected between individuals of sour orange; only four different genotypes were detected. Moreover the six SSR primers used in this work allowed the identification of four loci displaying unique alleles for the C. aurantium species, this result could have practical applications as an important tool for juvenile germplasm identification. Our research can be considered as a starting point for future gene conservations studies on C. aurantium from Central Italy.