Development of calibration equations to predict oil content and fatty acid composition in brassicaceae germplasm by near‐infrared reflectance spectroscopy

The use of nondestructive analytical methods is critical for the evaluation of very small seed samples such as those from germplasm collections. The objective of this study was to evaluate the potential of near‐infrared reflectance spectroscopy (NIRS) for the simultaneous analysis of seed oil content and concentration of major fatty acids in intact‐seed samples of the family Brassicaceae. A total of 495 samples from 56 genera and 128 species were analyzed by NIRS. The fatty acid composition of the seed oil was determined in all the samples by gas‐liquid chromatography (GLC). The total seed oil content was determined by solvent extraction in 129 samples from 22 genera. Calibration equations for oil content (n=97) and individual fatty acids (n=410) were developed and tested through external validation with the samples not included in the calibration sets. The calibration equations for oil content (r2=0.97 in validation) and concentrations of C18:1 (r2=0.93), C18:3 (r2=0.95), and C22:1 (r2=0.94) showed very good performance and provided reliable estimations of these traits in the samples of the validation set. The calibration equations for C16:0, C18:0, and C18:2 content were less reliable, with r2 from 0.67 to 0.73. There was practically no response of NIRS to differences in C20:1 (r2=0.31). These results demonstrated that the oil content and concentrations of C18:1, C18:3, and C22:1 can be estimated reliably within the family Brassicaceae by using NIRS calibration equations integrating broad taxonomic variability.