Nondestructive assessment of protein content in single seeds of rapeseed (Brassica napus L.) by near-infrared reflectance spectroscopy

The potential of near-infrared reflectance spectroscopy (NIRS) to detectwithin-plant differences for seed protein content was investigated. Fourhundred and fifty-one single seeds were scanned by NIRS using a specialadapter. After non-destructive NIRS scanning, the seeds were analysed forprotein content by the Dumas combustion method and a calibrationequation was developed. A validation set of 117 additional seeds fromthree individual plants from the cultivars Bristol, Lirajet and Maplus wasanalysed for protein content both by NIRS and combustion. The coefficientof determination between NIRS and combustion values in the validation setwas 0.94, with a standard error of performance (SEP) of 0.77% and aratio of the SEP to the standard deviation (SD) of the validation set of0.28. The coefficient of variation (CV) for seed protein content inindividual plants, as determined by the combustion method, was 11.7%for Bristol, 8.9% for Lirajet, and 9.5% for Maplus. The comparison ofsuch variation with the standard error (SE) of NIRS analysis, defined as thecombination of the SE of the combustion method and the SEP of NIRScalibration equation, revealed that the maximum explainable variance withinindividual plants that can be detected using NIRS analysis of proteincontent in single seeds was 0.86 for Bristol, 0.83 for Lirajet, and 0.85 forMaplus. These results demonstrated that NIRS is a powerful tool fornon-destructive assessment of within-plant variation for seed protein contentin rapeseed.