ABSTRACT
The building of multivariate calibration models using near-infrared spectroscopy (NIR) and partial least squares (PLS) to estimate the lignin content in different parts of sugarcane genotypes is presented. Laboratory analyses were performed to determine the lignin content using the Klason method. The independent variables were obtained from different materials: dry bagasse, bagasse-with-juice, leaf, and stalk. The NIR spectra in the range of 10 000-4000 cm-1 were obtained directly for each material. The models were built using PLS regression, and different algorithms for variable selection were tested and compared: iPLS, biPLS, genetic algorithm (GA), and the ordered predictors selection method (OPS). The best models were obtained by feature selection with the OPS algorithm. The values of the root mean square error prediction (RMSEP), correlation of prediction ( RP), and ratio of performance to deviation (RPD) were, respectively, for dry bagasse equal to 0.85, 0.97, and 2.87; for bagasse-with-juice equal to 0.65, 0.94, and 2.77; for leaf equal to 0.58, 0.96, and 2.56; for the middle stalk equal to 0.61, 0.95, and 3.24; and for the top stalk equal to 0.58, 0.96, and 2.34. The OPS algorithm selected fewer variables, with greater predictive capacity. All the models are reliable, with high accuracy for predicting lignin in sugarcane, and significantly reduce the time to perform the analysis, the cost and the chemical reagent consumption, thus optimizing the entire process. In general, the future application of these models will have a positive impact on the biofuels industry, where there is a need for rapid decision-making regarding clone production and genetic breeding program.
Subject(s)
Lignin/analysis , Lignin/chemistry , Saccharum/chemistry , Spectroscopy, Near-Infrared/methods , Algorithms , Cellulose , Least-Squares Analysis , Limit of Detection , Linear Models , Reproducibility of ResultsABSTRACT
O objetivo deste trabalho foi avaliar a adaptabilidade e estabilidade fenotípica de genótipos de cana-de-açúcar no estado de Minas Gerais. Foram avaliados 15 genótipos em nove ambientes. Os experimentos foram conduzidos em blocos completos casualizados, com três repetições. Para discriminar os genótipos, utilizou-se a variável TPH (toneladas de pol por hectare). Os valores corresponderam à média de dois cortes. Os resultados revelaram que a cultivar testemunha RB867515 apresentou maior adaptabilidade geral e estabilidade fenotípica, seguida pelo genótipo RB987935, que apresentou a maior média e elevada adaptabilidade geral e específica para ambientes favoráveis e desfavoráveis, podendo ser indicada para cultivo comercial.
The objective of this research was to evaluate the adaptability and phenotypic stability of genotypes of sugarcane in the state of Minas Gerais, Brazil. There had been evaluated 15 genotypes in nine environments. The experiments were conducted in a randomized block design with three replications. To discriminate the genotypes the variable TPH (tons of pol per hectare) was used. These values corresponded to the average of two cuts. The results showed that the check RB867515 presented greater general adaptability and phenotypic stability, followed by genotype RB987935, which had the highest average and high general and specific adaptability to favorable and unfavorable environments that may be suitable for commercial cultivation.
