On-Colony PCR was applied on norflorazon resistant colonies as follows: resistant colonies were picked and scraped from selection plates, mixed with ethanol and 5% Chelex®100 and then broken in Mini Beadbeater (Biospec products, OK, USA), using 2.5 mm glass beads for several rounds on ice. Colonies were then lysed by incubation at 98°C for 10 min, centrifuged and used for PCR with primers corresponding to 500 bp region including the mutation site of pds sequence: F-AGCTTGCTCTGCTGTGCCAG, R-GCTATTGCACCACTGGCTGC. PCR product was extracted from gel as described previously and sent for sequencing.