关键词: 近红外光谱, 高粱, 直链淀粉, 支链淀粉, 改进最小二乘法

Abstract:

【Objective】 Sorghum is one of the main raw materials for wine making and feed. The ratio of amylose content to amylopectin content in its grains is closely related to liquor quality and feed quality. Traditional chemical detection methods of sorghum components are no longer suitable for high-throughput testing. Modified PLS is used to perform spectral preprocessing, score processing and result monitoring on the near-infrared spectra of sorghum samples to establish sorghum grain amylose and amylopectin. The prediction model of amylose content aims to obtain a fast, efficient and low-cost detection method, laying the foundation for genetic improvement and quality analysis of sorghum. 【Method】 From 450 sorghum resources, 112 representative varieties were selected as calibration set and verification set. The chemical values of amylose and amylopectin content in 112 sorghum varieties were measured, and near-infrared spectra with wavelengths of 850-1 048 nm were collected, and the spectrum was scanned data matrix and chemical data calculated score (PL1) processing and interpreting the differences between the spectra, and eliminating abnormal species with Global H (GH) greater than 3 to reduce modeling errors. Modified PLS regression technology is used for modeling, and different calibration models are established through different scattering processing and derivative processing methods. Determine the best model according to the cross-validation standard deviation (SECV) and cross-validation correlation coefficient (1-VR), and perform result monitoring and non-parametric testing to evaluate the predictive performance of the model.【Result】 The near-infrared prediction model SECV of amylose is 2.7732, 1-VR is 0.9503, and the correlation coefficient (RSQ) is 0.9688. Bias=0.229<2.7732(SECV)×0.6, that is, the deviation (Bias) is less than 0.6 times of the calibration model SECV; the predicted standard deviation (SEP)=1.266<2.7732(SECV)×1.3=3.60516, that is, the SEP is less than the calibration. The model SECV is 1.3 times, 11.01(SD)-10.81(SD)=0.2<11.02(SD)×0.2=2.204, that is, the difference between the standard deviation (SD) of the chemical data and the near-infrared prediction data is less than 20% of the chemical data SD. The near-infrared prediction model SECV of amylopectin is 1.7516, 1-VR is 0.8818, and RSQ is 0.9127. Bias=-0.014<1.7516(SECV)×0.6 means that Bias is less than 0.6 times of SECV of calibration model, SEP=1.316<1.7516(SECV)×1.3=2.2708 means SEP is less than 1.3 times of SECV of calibration model, 5.30-5.29=0.01<5.30×0.2=1.06, that is, the difference between the chemical data and the near-infrared prediction data SD is less than 20% of the chemical data SD. Using 30 sorghum grains outside the model to conduct a two-pair sample non-parametric test on the validity of the model, the results showed that the difference between the measured and predicted values of amylose content and amylopectin content was not significant (P=0.262>0.05; P=0.992>0.05).【Conclusion】 The established near-infrared model has high accuracy and good stability, can accurately and quickly detect the content of amylose and amylopectin in sorghum, and can be used for the genetic improvement of sorghum and the detection of sorghum quality.

Key words: near infrared spectroscopy, sorghum, amylose, amylopectin, improved least squares method