Thirteen reference genes surveyed in this work with their amplification and expression characteristics in Saccharum officinarum.

Mean Ct values and RNA concentration were used for calculating slopes and correlation coefficients (R2). According to the formula [E = (10(−1/slope)−1)×100%, qPCR efficiencies (E) were calculated based on the standard curves. Mean Ct value (mean), Standard deviation (SD) and Covariance (CV) were calculated by Microsoft Excel 2003 and the Ct values from all of the samples were used. The sequence numbers were obtained from www.ncbi.nlm.nih.gov/nucest/?term=sugarcane.