J Appl Genetics (2012) 53:237–247 Table 4 Codes and sequences of random amplified poly- morphic DNA (RAPD) primers tested, with polymorphic RAPD marker numbers and sizes 243 Primer code Sequence 5′-3′ Polymorphic band number Polymorphic band size (bp) OPB-07 OPC-02 OPC-04 OPC-08 OPC-15 OPJ-10 +A OPL-11 OPL-12 OPL-19 GGTGACGCAG GTGAGGCGTC CCGTATCTAC TGGACCGGTG GACGGATCAG AAGCCCGAGGA ACGATGAGCC GGGCGGTACT GAGTGGTGAC 7 7 – 0 4 4 5 6 – a-720, b-880, c-1000, d-1470, e-2280, f-2400, g-3200 a-390, b-800, c-980, d-1300, e-1460, f-1500, g-2600 Rejected Monomorphic a-850, b-1150, c-1500, d-1850 a-660, b-1250, c-1370, d-2630 a-340, b-500, c-600, d-810, e-2010 a-700, b-910, c-1000, d-1130, e-1380, f-1840 Rejected the lowest genetic similarity (equal to 0.0667) was found for O-02 and O-12. The average value of genetic similarity was equal to 0.507. Significant associations of eight markers (OPC-02b, OPC- 15 d, OPL-11c, OPL-11 d, OPL-11e, OPL-12 d, OPL-12f and OPB-07b) with FB1 biosynthesis (Table 5) as well as one marker (OPC-15b) with MON production were found (Fig. 3). The percentage variation of FB1 concentration accounted by markers ranged from 11.2% (for OPB-07b) to 26.5% (for OPL-11c). In the case of MON concentration, the percentage variation accounted by OPC-15b marker was equal to 56.8%, which makes this marker a good candidate for further studies. Discussion When considering Fusarium fungi as mycotoxin producers, a proper identification of species infecting food and/or feed plants is very important. Traditional diagnostics based on Fig. 2 Dendrogram of F. oxysporum isolates based on random amplified polymorphic DNA (RAPD) data analysis; the isolates were grouped hierarchically using the unweighted pair group method of arithmetic means (UPGMA). *Isolates with MAT1-1 idiomorph