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

Regiane Abjaud Estopa,Flaviana Reis Milagres,Ricardo Augusto Oliveira,Paulo Ricardo Gherardi Hein

doi:10.1590/01047760201723032319

Regiane Abjaud Estopa, Flaviana Reis Milagres + Show 2 more

Open Access

https://doi.org/10.1590/01047760201723032319

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Abstract

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.

Highlights

Brazil has become a reference in Eucalyptus forestry due to its great advances in traditional breeding and improvements in forestry management practices
A progeny test conducted with 81 mother plants of 4-year-old E. benthamii located at the municipality of Otacílio Costa (geographic coordinates (27o 28’ 59” S, 50o 07’ 19” W, 884 m) in Santa Catarina state, Brazil, was investigated for the wood characterization and NIRbased models development
The Partial Least Squares (PLS)-R models for estimating lignin and extractive contents presented acceptable predictive ability indicating that the estimates presented small errors and can be applied in breeding programmes of Eucalyptus benthamii

Summary

Introduction

Brazil has become a reference in Eucalyptus forestry due to its great advances in traditional breeding and improvements in forestry management practices. Eucalyptus benthamii is a species of commercial importance in Southern Brazil because it is highly resistant to cold, and it presents good adaptation and volumetric growth The breeding of this species is very recent, with current strategies focusing on selecting intraspecific and multi-species hybrids, i.e., hybrid individuals that combine several important features to increase yield, resistance to cold, and, in particular, the quality of wood suitable for pulp production. Non-destructive evaluation methods are required to enable the collection of a small wood sample without compromising the survival of the individual Another important factor is wood assessment age, given that wood properties can only be determined after a tree has reached its harvest age (PASQUINI et al, 2007), which hinders selection time and generation advancement. The minimum optimal assessment age that allows a good correlation with the quality of 7-year-old wood must be determined to enable earlier breeding (SCHIMLECK et al, 2005)

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