Genetic control of very early compression and opposite wood in Pinus radiata and its implications for selection

Abstract

The long time frame for evaluating selection candidates is a major barrier to the deployment of genetic gain from tree breeding programs. This situation is compounded in wood quality studies by constraints on the number of sampled individuals when trees are older and larger. This paper documents the degree of genetic control and genetic association for wood quality traits in 18-month-old leaning Pinus radiata seedlings. Trees were separately assessed for basic density, green and dry acoustic velocity, and longitudinal and volumetric shrinkage in opposite and compression wood. Heritability estimates were low to moderate for both compression and opposite wood (ranging from 0.15 to 0.38). Estimated genetic correlations were very high in opposite wood, where green velocity displayed the highest correlations with both longitudinal (−0.89) and volumetric (−0.64) shrinkage, closely followed by dry velocity. These correlations were substantially lower for compression wood. The estimated correlations between compression and opposite wood characteristics were high for most traits except for longitudinal shrinkage. We suggest how these results could be used for very early screening for wood stiffness and dimensional stability. We propose that information on early genetic control of wood quality and the methodologies used to elicit it should be integrated in breeding and deployment programs.

Genetic Improvement of Wood Properties in Pinus kesiya Royle ex Gordon for Sawn Timber Production in Malawi

“…The within-family heritability estimate was one third due to the mixed mating that is expected in Pinus species [13], rather than one quarter as is appropriate for true half-sibs [20]. Standard errors of heritabilities were estimated by the Delta method and PROC IML in SAS.…”

“…Therefore, improved wood density trait is expected to meet a wide range of demands and potential for future utilization. Current studies [9][10][11][12][13] have indicated that wood density, with high heritability and large economic gain from selection, is an ideal selection criterion for tree breeding programmes because of its strong effect on wood quality. Heritability of wood density is generally found to be higher than those of growth traits in forest trees.…”

Characterization of mechanically perturbed young stems: can it be used for wood quality screening?

“…1). Then, two independent sets of wood quality traits can be gathered, for compression wood and opposite wood (Apiolaza et al 2011).…”

Effects of induced drought and tilting on biomass allocation, wood properties, compression wood formation and chemical composition of young Pinus radiata genotypes (clones)

“…Clone 31, with the highest velocity (V dx ), had the lowest LS, and clone 708, with the lowest velocity, had the highest LS. In 18-month-old P. radiata plants, both green and V dx data were highly negatively correlated with LS and volumetric dimensional shrinkage (Apiolaza et al 2011b). Acoustic measurements coupled with mechanical perturbation have a high potential as an early screening tool for dimensional stability, as suggested in the literature (Lindstrom et al 2002(Lindstrom et al , 2005Apiolaza et al 2011b) …”

“…The heritability of CW has been reported to be significantly high ranging from 0.3 to 0.9 (Shelbourne et al 1969;Apiolaza et al 2011b). Genotypes showed differences in their propensity to form CW at age 12 (Burdon 1975).…”