Reverse transcription polymerase chain reaction (RT-PCR) for the detection of UCBSV (440 bp top panel) and CBSV (344 bp, middle panel) in a dual challenge experiment. Lane M at each border is 1 kb + molecular marker (Invitrogen), Treatment 1 (samples 1–5), Treatment 2 (sample 6–10) and Treatment 3 (samples 11–15). Lane 16 is a non-grafted plant of 60444, lane 17 is PCR water negative control and lane 18 is a positive control for each virus. Rubisco (bottom panel) was run to demonstrate cDNA quality. Cassava leaves were sampled 7–9 weeks after chip bud inoculation and data shown for one of the two replicated experiments.