For the rapid detection of SPAD value of cucumber leaves,the calibration model of SPAD value was built by using visible and near infrared(Vis/NIR) spectroscopy technique and chemometrics methods.Different calibration methods were used to build the model in the whole wavelength region.The results indicate that the optimal performance is achieved by least squares support vector machine(LSSVM) model,and the correlation coefficient(r) and root mean squares error of prediction(RMSEP) are 0.9583 and 0.9732,respec...