NIR SPECTROSCOPIC MODELS FOR PHENOTYPING WOOD TRAITS IN BREEDING PROGRAMS OF Eucalyptus benthamii

Abstract

Wood characterization must be done in huge populations of Eucalyptus breeding programs in order to efficiently select potential trees. In this study, Eucalyptus benthamii wood was non-destructively characterized and the performance of near infrared (NIR) spectroscopy in estimating the wood basic density, lignin, extractive, glucose, xylan contents and total carbohydrates was evaluated. NIR models for wood traits were performed from 481 trees from E. benthamii progeny test (4-year-old) managed for pulp cultivated in Santa Catarina state, Southern Brazil. Increment cores were sampled for chemical and physical characterization in laboratory, as well as for NIR spectroscopy analyses. Three 350 samples were selected from PCA for model calibrations whereas 131 were reserved for independent test validation. The E. benthamii wood presented the standards required for Kraft pulp processing. The predictive NIR models showed satisfactory ability for estimating the chemical properties of wood. The prediction models for total lignin, extractive and xylan contents and total carbohydrates showed coefficients of determination of 0.53, 0.65; 0.36 and 0.53, with RPD values for these traits ranging from 1.3 to 2.3. The predictive model for basic density of wood and glucose presented low coefficient of determination (0.13 and 0.10). However, isn't possible to use these models for ranking in genetic selection because there was no correlation. Therefore, NIR spectroscopy can potentially be applied in breeding programs, as it enables an early, non-destructive selection of trees with adequate physical and chemical properties for pulp production process. MODELOS DE ESPECTROSCOPIA NIR PARA FENOTIPAGEM DAS CARACTERÍSTICAS DA MADEIRA EM PROGRAMAS DE MELHORAMENTO DE Eucalyptus benthamii RESUMO:A caracterização da madeira deve ser feita em grandes populações dos programas de melhoramento de eucaliptos, a fim de selecionar eficientemente árvores potenciais. Neste estudo, a madeira de E. benthamii foi caracterizada de forma não destrutiva e avaliou-se o desempenho da espectroscopia de infravermelho próximo (NIR) na estimativa da densidade básica da madeira, lignina, extrativos, glicose, xilanas e carboidratos totais. Modelos NIR para características da madeira foram realizados a partir de 481 árvores do teste de progênie de E. benthamii (4 anos de idade) destinada a produção de celulose no estado de Santa Catarina, no sul do Brasil. Baguetas foram amostrados para caracterização química e física em laboratório, bem como para análises de espectroscopia NIR. 350 amostras foram selecionadas via PCA para calibrações de modelos, enquanto 131 foram reservadas para o teste de validação independente. A madeira de E. benthamii apresentou os padrões exigidos para processo de polpa Kraft. Os modelos preditivos NIR apresentaram capacidade satisfatória para estimar as propriedades químicas da madeira. Os modelos de predição para teores totais de lignina, extrativos, xilanas e carboidratos totais apresentaram coeficientes de determinação de 0,53, 0,...

DEVELOPING NEAR INFRARED SPECTROSCOPIC MODELS FOR PREDICTING DENSITY OF Eucalyptus WOOD BASED ON INDIRECT MEASUREMENT

“…Treatments performed in the spectra were: exclusion of wavelengths with presence of noise, removal of anomalous samples (outliers) and first derivative (13-point filter and a second-order polynomial using Savitzky-Golay algorithm), in search of improvement in the performance of the models. The best models were selected based on the coefficient of determination of calibration (R 2 c) and cross validation (R 2 cv), root mean standard of calibration error (RMSEc) and cross validation (RMSEcv), number of latent variables (LV) used in the models and the ratio to performance deviation (RPD) as suggested by Estopa et al (2017).…”

“…In these studies, the development of models for predicting the basic density of wood was carried out based on NIR spectra associated to the basic density values of the wood coming from the transverse face of the wood disk (Alves et al, 2012;Baettig et al, 2017;Fujimoto et al, 2012;Pfautsch et al, 2012), or core (Schimleck et al, 2005;Estopa et al, 2017) removed from the trunk at breast height (~1.3 m). Thus, most of the predictive models have been based on spectral signatures and basic density values obtained directly in the same sample.…”

Challenges in the use of Near Infrared Spectroscopy for improving wood quality: A review

“…They stated that multi-trait selection for growth and wood properties can lead to more productive populations of E. pellita with improved productivity and wood and pulp properties. Estopa et al (2017) applied NIR-based models for estimating chemical properties of Eucalyptus benthamii wood at 4 years old. They stated that the lignin and extractive estimates can be applied in breeding programmes of E. benthamii for early selections.…”

Genetic variation in wood properties of mid-rotation age Eucalyptus globoidea

“…Felling trees and sawing wood samples is destructive and too laborious for routine use in a breeding programme. A rapid means to obtain a heartwood sample without damaging the tree is taking increment cores (Estopa et al 2017;Jones et al 2008).…”

“…Nearinfrared (NIR) spectroscopy has been proven effective in predicting the extractive content in wood Li et al 2018;Stackpole et al 2011). NIR spectra can be acquired within seconds from a solid wood surface and are an inexpensive method for assessing the chemical components of wood (Estopa et al 2017;Greaves et al 1996;Tsuchikawa & Schwanninger 2013). NIR calibrations for the extractive content were reported to have a root mean square error (RMSE) of 0.91% to 1.16% for E. bosistoana F.Muell.…”