Fig germplasm characterization using isozyme analysis

Within the Sardinian fig germplasm, more than thirty varieties have previously been described and characterized in their main morphological characters. Most of them are autochthonous and all are of the "common type". A collection field was established, where all the fig varieties are maintained and evaluated under controlled conditions. Characterization of germplasm fig varieties has been conducted by means of isozymes electrophoresis on horizontal starch gel applied on cork tissue. Seventeen enzyme systems have been analyzed, and the following: acid phosphatase (AcPH), diaphorase (DIA), fumarase (FUM), glutamate oxalacetate transaminase (GOT), malate dehydrogenase (MDH), peroxidase (PRX) and phosphoglucoisomerase (PGI) have shown high resolution of the bands and reproducibility of the analysis. The results obtained showed that only FUM had a monomorphic pattern, while the other enzymes tested proved to be useful to allow the characterization of almost all fig varieties. The AcPH and GOT systems showed high variability with respectively six and five different banding patterns, while DLA, MDH and PGI had four banding patterns and PRX three. The degree of electrophoretic similarity between varieties was determined by calculating a similarity index value based on three enzyme systems: AcPH, GOT and MDH.