Comparison of Accessions Conserved in Different Litchi Germplasm Collections Using Microsatellite Markers

One of the main limitations for breeding purposes and optimum germplasm management in litchi is the confusion in cultivar denomination among different litchi-producing countries and germplasm collections worldwide that results in a high number of homonymies and synonymies. In this work, we have characterized 88 litchi accessions conserved in three different germplasm collections (Mauritius, Reunion and Spain) using microsatellite markers. A total of 11 simple sequence repeat (SSR) loci were used that yielded 67 amplification fragments, with an average of 6.1 amplification bands/SSR. Eight primer pairs amplified single loci in the accessions examined. The mean expected and observed heterozygosities over those 8 single locus SSRs averaged 0.53 and 0.61, respectively, with a value for the probability of identity of 9.78x10(-4). A total of 42 different genetic profiles were found among the 88 samples analyzed and several synonymies and homonymies both within and among the germplasm collections were found. No clear geographical trends could be observed among the groups obtained in the UPGMA dendrogram. The results demonstrate the usefulness of these kinds of molecular markers for the optimization of litchi germplasm management and they will be discussed in terms of their implications for the standardization of litchi cultivar nomenclature over the studied germplasm collections and in other litchi-producing countries in order to have a clear picture of current litchi germplasm conservation worldwide.