Genetic parameters for growth and wood chemical properties in Eucalyptus urophylla × E. tereticornis hybrids

Abstract

& Key message Growth and wood chemical properties are important pulpwood traits. Their narrow-sense heritability ranged from 0.03 to 0.49 in Eucalyptus urophylla × E. tereticornis hybrids, indicating low to moderate levels of genetic control. Genetic correlations were mostly favorable for simultaneous improvement on growth and wood traits. Additive and non-additive genetic effects should be considered in making a hybrid breeding strategy. & Context Eucalypt hybrids are widely planted for pulpwood production purposes. Genetic variations and correlations for growth and wood chemical traits remain to be explored in Eucalyptus interspecific hybrids. & Aims Our objectives were to clarify the heritability of growth and wood chemical traits and determine the genetic correlations between traits and between trials in E. urophylla × E. tereticornis hybrids. & Methods Two trials of 59 E. urophylla × E. tereticornis hybrids derived from an incomplete factorial mating design were investigated at age 10 for growth (height and diameter) and wood chemical properties (basic density, cellulose content, hemicellulose content, lignin content, and syringyl-to-guaiacyl ratio). Mixed linear models were used to estimate genetic parameters. & Results Narrow-sense heritability estimates were 0.13−0.22 in growth and 0.03−0.49 in wood traits, indicating low to moderate levels of additive genetic control. Genetic correlations were mostly positively significant for growth with basic density and cellulose content but negatively significant with hemi-cellulose and lignin contents, being favourablefavorable for pulpwood breeding purpose. Type-B correlations between sites were significant for all the traits except diameter and lignin content. & Conclusion Hybrid superiority warrants the breeding efforts. An appropriate breeding strategy should be able to capture both additive and non-additive genetic effects.

Genetic Parameters in Fibre Traits From a Full Diallel of Eucalyptus Urophylla in Southern China

“…Fine percent had higher SCA estimation and mean curl had smaller GCA estimation (Table 7). SCA estimation for fibre length was relatively higher Estimates of specific combining ability are given for the top 10 values Estimates of heritability for fibre traits were low to medium for fibre percent (0.01) and fibre width (0.19), which were in general agreement with the eucalypt hybrids studied by Zhu et al (2017) (0.04) and Chen et al (2018) (0.06-0.49). Heritability of fibre width was higher than that of fibre length, indicating more genetic gain could be obtained from fibre width by genetic improvement as previously found by Wu et al (2011).…”

“…High genetic correlation value between growth traits and wood properties had been widely described in Eucalyptus and other species (Kien et al 2009, Kube et al 2001, Wu et al 2011, Chen et al 2018. High genetic correlation indicates that the expression of both traits is most likely controlled by the same class of genes in an organism (Chen et al 2018).…”

“…It has since become a very important plantation species in tropical and subtropical areas in China (Chen et al 2006, He et al 2012. More than 50% of widely used clones in China were established with germplasm derived from E. urophylla and interspecific hybridisation with E. urophylla via controlled pollination (Luo et al 2010, Wu et al 2013, Chen et al 2018. Comprehensive research results about provenance trials, family tests and clone selection of E. urophylla were published in recent years (Retief & Stanger 2009, Andrade et al 2013.…”

Quantitative genetic parameters for growth and wood properties in Eucalyptus “urograndis” hybrid using near-infrared phenotyping and genome-wide SNP-based relationships

“…grandis [26] and E . urophylla [27–29]. Recently, a comprehensive study has developed global NIRS models using wood samples from different tropical, subtropical, and temperate eucalypt species grown in different locations around the world, but unfortunately no samples of urograndis hybrids were included [30].…”

Intra-and intergenotypic competition among commercial eucalyptus clones

“…Evaluating E. urophylla x E. tereticornis hybrid performance at 10 years of age, Chen et al (2018) observed environmental coefficients of variation from 30 to 43% for DBH and from 23 to 30% for height. Evaluating trees at several ages, Li et al (2017) observed values of environmental coefficients from 11.7 to 23.7% for height, 13.5 to 26.6% for DBH, and 31.6 to 53.8% for wood volume in E. cloesiana progenies.…”