AFLP analysis was performed following the method of Vos et al. (1995) with minor modifications. For each sample, the templates were prepared by digesting 250 ng DNA with the restriction enzyme combination EcoRI-MseI and by ligating with T4 DNA ligase (Fermentas; Burlington, Ontario, Canada) the corresponding oligonucleotide adaptors in a total volume of 10 μL. The ligation products were diluted 10 times with deionized H2O. Pre-selective PCR amplification with primers corresponding to adaptor core sequences (E+A and M+C) was performed in a 25 μL reaction containing 2.5 μL of AFLP template. PCR contained 1X PCR buffer [750 mM Tris-HCl (pH 8.8 at 25 °C), 200 mM (NH4)2SO4 0.1% (v/v)], 1.5 mM MgCl2, 0.2 μM of each primer, 0.2 mM dNTP and 1U Taq DNA polymerase and was performed using the T1 Thermocycler. The temperature profile for preamplification involved: 20 cycles: 30 s at 94 °C for DNA denaturation, 1 min at 56 °C for annealing, and 1 min at 72 °C for extension, and finally a hold for 5 min at 72 °C