Nondestructive identification of hard seeds of three legume plants using near infrared spectroscopy

To explore the applicability of the NIRS on nondestructive identification of hardseedness characteristics, in this study, near infrared spectroscopy (NIRS) models were established using near-infrared spectroscopy combined with Partial Least squares (DPLS) to investigate the hard seed characteristics of legume seeds, Codariocalyx motorius Glycine max Cassia tora L.and Sophora alopecuroides. 120 seeds of the three species were divided into two groups: calibration set (80 samples) and validation set (40 samples), which contained the same number of hard seeds and soft seeds. The influences of replicate times, spectral region and calibration samples on the discrimination rate were compared. The results showed that with 4 000-5 000 cm-1 of spectral range, vector correction, eight main components, the predictive value of the model fitted with the true value well. Discrimination rates of calibration and validation sets in NIR models were over 85% for Glycine max. With 4 000-8 000 cm-1 of spectral range, first-derivative spectroscopy, four main components, discrimination rates of calibration and validation sets were about 90% for Cassia tora L. With 4 000-8 000 cm-1 of spectral range, second derivative spectroscopy, eight main components, discrimination rates of calibration and validation sets were over 95% for Sophora alopecuroides.