To generate calibration curves, DNA extracts were adjusted at 100 pg/μl in the NucleoSpin Plant II kit elution buffer, and were then serially (1:10) diluted, resulting in a six point calibration curve range of 100 to 0.001 pg/μl. QPCR analysis was repeated three times for each concentration. For each qPCR assay, the calibration curve allowed us to calculate the linear dynamic range, the limit of detection (LOD) and PCR amplification efficiency. The linear dynamic range is the concentration range over which the quantification cycle (Cq) and concentration remain directly proportional to each other. Range interval and correlation coefficient (r2 value) were then reported. The LOD was the lowest concentration at which DNA was detected in all three samples. PCR amplification efficiency was established as the slope of the log–linear portion of the calibration curve: PCR efficiency = 10− 1/slope − 1.