DNA FINGERPRINTING OF CORYLUS AVELLANA L. ACCESSIONS REVEALED BY AFLP MOLECULAR MARKERS

In recent years several PCR based approaches have been designed to develop molecular markers for many plant systems including fruit crop species. AFLP (Amplified Fragment Length Polymorphism) is one of these approaches, and has the advantage of providing a high (30-100 “loci”) ‘multiplex ratio’ for primer combination. It has therefore become a popular approach for identifying molecular markers for varietal fingerprinting. In Corylus avellana L. varietal fingerprinting has so far been performed using low ‘multiplex ratio’ PCR-based techniques (RAPD and SSR). Here we present the results to assess the potential usefulness of this methodology for fingerprinting 57 hazelnut clones from accessions of different Italian and foreign geographical origin. The reproducibility of the detected DNA fragment profiles is of utmost importance for varietal fingerprinting; therefore, we investigated the appropriateness of an automated analysis system based on fluorescent AFLP electropherogram generated by an automated DNA sequencer (ABI 310) for the reproducible AFLP results. The Fragment selection was performed by the software Gel Compare II on the basis of optimal settings for thresholds based on the average fluorescent fragment signal intensity. Two different sampling effects on reproducibility were studied: (a) the effect of DNA pool-sampling (from two plants of the same clone) on the reproducibility of the AFLP pattern and (b) the effect of sampling the combined inconsistencies of instrument performance and PCR mixture preparation. Similarities among replicates ranged between 75 and 90% and changed according to the primer-pair sets used for amplification and the band search filter adopted to generate the computerized AFLP band pattern.