Festulolium is an excellent temperate grass. Festulolium was cultivated in the test field; the leaves of 163 strains were sampled during the second and third herbaceous internode elongation stages, vacuum freeze dried and crushed, and chemically assayed for total polyphenols, α-tocopherol, lutein and β-carotene content. The calibration curve was generated by the usual PLSR method and the wavelength selective PLSR method, using the near-infrared spectrum and the chemical analysis value of the crushed leaves. The R²cv (Coefficient of determination of cross-validation) and RPD (Ratio of standard error of standard deviation of reference data in predicted sample set to Standard error of cross-validation) of the total polyphenol content were 0.865 and 2.693 for the PLSR method, 0.930 and 3.772 for the Iterative Stepwise Elimination PLSR (ISE-PLSR) method, and 0.897 and 3.108 for the (Genetic Algorithm PLSR) GA-PLSR method, respectively, and can be estimated with practical accuracy. The R²cv and RPD of α-tocopherol content were 0.425 and 1.302 for the PLSR method, 0.473 and 1.378 for the ISE-PLSR method, and 0.495 and 1.406 for the GA-PLSR method, respectively, and could be estimated with rough accuracy. The R²cv and RPD of β-carotene content were 0.562 and 1.504 for the PLSR method, 0.589 and 1.558 for the ISE-PLSR method, and 0.648 and 1.683 for the GA-PLSR method, respectively, and could be estimated with rough accuracy, The R²cv and RPD of lutein were 0.429 and 1.299 for the PLSR method, 0.621 and 1.589 for the ISE-PLSR method, and 0.474 and 1.377 for the GA-PLSR method, and their estimation was possible with rough accuracy.
Perennial ryegrass (Lolium perenne L.) is valuable for use in cool seasonal lawns and is widely used as fodder for grazing and forage crops. It is rich in chlorogenic acid as a functional ingredient. In the future, it is likely that breeding with a focus on this acid may be established. Hence, the development of a simple and rapid method for the estimation of chlorogenic acid content is required. In this study, a calibration curve of the chlorogenic acid content of perennial ryegrass was obtained using near-infrared spectroscopy. Subsequent analysis of the data was based on the partial least squares method (PLSR) with full-spectra information to contribute to the estimation of the target components. The iterative stepwise elimination PLSR (ISE-PLSR) method and genetic algorithm PLSR (GA-PLSR), as a wavelength selective PLSR method for eliminating non-existent wavelength information or selecting useful wavelength information, were also utilized. The estimation accuracies of the approaches were compared using the determination coefficient (R²) and the residual prediction deviation (RPD). The ISE-PLSR method based on the second derivative absorbance (SDA) spectrum resulted in an R² of 0.872 and an RPD of 2.728. These values were more accurate compared to the other methods (R² = 0.803 - 0.847, RPD = 2.309 - 2.533). Because RPD> 2.43, it can be concluded that the ISE-PLSR model using the SDA spectrum exhibited high accuracy.