An empirical model for the estimation of starch content (SC) and dry matter (DM) in cassava tubers was developed as an alternative method to polarimetry and dry oven. These improved estimation equations were developed based on the specific gravity (SG) method. To improve accuracy, the one hundred-seventy-four sample were obtained from four commercial varieties of cassava in Thailand including KU50, CMR38-125-77, RY9 and RY11, respectively. The age of sample collected from four to twelve months after planting was used in this experiment. The empirical model was created from their relationships between SG obtained from small sample size (~100 g) and its SC and DM. The SG for cassava was strongly correlated with the SC and DM, with values for the coefficient of determination (R2) of 0.81 and 0.83, respectively. The SC showed a high correlation with the DM, with R2 of 0.96. To confirm that the empirical model was effective when applied to other samples, unknown samples collected from another area were tested, and the results showed a standard error of prediction (SEP) of 1.02%FW and 3.49%, mean different (MD) of -0.66%FW, -0.89% for the SC and DM, respectively. Hence, our empirical equation based on a modified SG method could be used to estimate the SC and DM in cassava tubers. It can help breeders to reduce costs and time requirements. Moreover, breeders could be used the methods to evaluate the SC and DM from the tuber formation to harvesting stage and monitoring the changes in SC and DM during breeding.

Near infrared spectroscopy can be applied as a rapid and non-destructive method for monitoring sugarcane quality after determining the precision and accuracy of the approach and model to be used for evaluating stems. In this study, near infrared spectroscopy has been applied to breeding management systems and commercial sugar production. Near infrared spectra were collected using a portable near infrared instrument incorporating a wavelength region of 730–1000 nm. To achieve an effective sampling technique, the investigated cane samples included stems with original cane surface and stems with cane wax removed surface. Results revealed that calibrations based on spectra recorded at only 1-position (1-position spectra) of original samples were poor, while calibrations based on stems with wax removed were acceptable for screening with RMSEP values of 1.2%Pol. Also, the 2-position averaged spectra of non-removed wax samples provided fair models, while 4- and 8-position averaged spectra gave good results with R² of 0.78–0.82, r² of 0.78–0.82, RMSEP of 1.2%Pol to 1.4%Pol and RPD of 2.1 to 2.4, respectively. The calibration model developed from removed-wax samples at positions 1-, 2-, 4- and 8-averaged spectra rendered effective performances with R² of 0.73–0.82, r² of 0.73–0.84, RMSEP of 1.2%Pol to 1.5%Pol and RPD of 2.1 to 2.5. Outcomes were not different in performance, even if the scanned positions and number of scans differed. Hence, the author concluded that 1-position spectra with removed-wax samples were convenient and suitable for the measurement of cane stalk Pol value.

Hyperspectral imaging is a powerful technique that can rapidly, accurately, and non-destructively determine the quality of agricultural products. In this study, a hyperspectral imaging system has been developed to evaluate and visualize the Brix values and moisture contents in sugarcane stalks to be used as a tool for breeding programmes. After extracting the spectral data via ENVI coding, data in the wavelength range of 450–950 nm were used to generate prediction models for Brix and moisture content via partial least squares regression. The coefficients of determination of the predictive models for Brix and moisture content were found to be 0.70 and 0.68, respectively. The root mean square errors of cross-validation were 1.28° for Brix and 1.49% for moisture content, and the performance to deviation ratios were 1.71 and 1.61, respectively. The models were applied to each pixel of the hypercube data in order to determine the distributions of Brix and moisture content within the sugarcane stalks. Both distribution mappings indicated that the Brix and the moisture content level were lower in the internode regions. The results demonstrated the feasibility of using hyperspectral imaging to visualize Brix and moisture content in sugarcane stalks. The developed method has potential applications in farming management and also in breeding programs.