Near-infrared reflectance spectroscopy (nirs) for the determination of tryptophan content in quality protein maize (qpm)

Quality protein maize (QPM) has approximately twice tryptophan (Trp) and lysine (Lys) concentrations in protein compared to normal maize. Because several genetic systems control the protein quality of QPM, it is essential to regularly monitor Trp and/or Lys in QPM breeding programs. The objective of the study was to evaluate the capability of NIRS method in determining tryptophan content of QPM which enhance the efficiency of QPM research efforts by partially replacing more expensive and time-consuming wet chemistry analysis. 268 maize samples were used to develop NIRS models for Tryptophan content. Standard error (SEC) and coefficient of determination for the calibration were 0.007 and 0.76 respectively. When the NIRS model was subjected to external validation with 40 S2 lines from QPM breeding populations, the standard error of prediction (SEP) for validation and coefficient of determination between NIRS and the chemical data were 0.008 and 0.84 respectively . Therefore, from the result it is confirmed that NIRS model is effective tool for screening of QPM from normal maize.