scholarly journals Genetics of Shrinkage in Juvenile Trees of Pinus radiata D. Don From Two Test Sites in Australia

2008 ◽  
Vol 57 (1-6) ◽  
pp. 145-151 ◽  
Author(s):  
W. J. Gapare ◽  
M. Ivković ◽  
M. B. Powell ◽  
T. A. McRae ◽  
H. X. Wu

Abstract To examine the genetic control of wood shrinkage (radial, tangential and longitudinal) in juvenile wood of radiata pine (Pinus radiata D. Don), we assessed samples collected at breast height in two related progeny tests of age 8 and 9 years, established at two different sites in Australia. Green to oven-dry tangential and radial shrinkage for the outer-rings was similar at both sites. Similarly, mean longitudinal shrinkage for the outer-rings was similar at both sites (0.3%, ranging from 0.1 to 1.9 at Flynn and 0.4%, ranging from 0.02 to 1.6, at Kromelite). Mean longitudinal shrinkage for the inner-rings was 4 times greater than that of the outerrings at both sites. The magnitude of the gradient of longitudinal shrinkage from pith to bark (0.001 to 2.9%) is large enough to cause distortion problems including twist and warp, during drying of sawn boards. These values also suggest that shrinkage in the juvenile core of radiata pine is of major economic importance and therefore should be improved either through genetics or silviculture. Individual-tree narrow-sense individual heritability for tangential and radial shrinkage in the outer-rings (4-6) was moderate at Flynn (0.24 ± 0.09 and 0.26±0.07, respectively). There was a lack of significant genetic variation for longitudinal shrinkage in the outer-rings but significant genetic control for the inner-rings (1-2) (h2 = 0.26 ± 0.07). More samples per family are required to detect significant genetic variation for shrinkage traits than other traits due to higher background variation in sampling and measuring shrinkage traits relative to other wood quality traits such as density, microfibril angle (MfA), spiral grain and modulus of elasticity (MoE).

2008 ◽  
Vol 38 (1) ◽  
pp. 63-72 ◽  
Author(s):  
Rafael Zas ◽  
Luis Sampedro ◽  
Xoaquín Moreira ◽  
Patricia Martíns

The effects of establishment fertilization and pine genotype on pine weevil ( Hylobius abietis L.) damage was studied in a radiata pine ( Pinus radiata D. Don) naturally infected family × fertilization genetic trial in Galicia (northwestern Spain). Fertilization strongly increased both growth and H. abietis damage, especially when calcium phosphate was included in the fertilization treatment. Fertilized plants showed higher degree of debarking, greater leader loss, and higher mortality than unfertilized controls. Because of the greater leader loss, fertilization did not significantly increase the actual height (height of live stem) 1 year after planting. In contrast, after the second growing season, fertilized plants overcompensated for the weevil damage and reached greater height than the unfertilized controls. However, considering the effects on survival and the stem deformities resulting from the leader losses, fertilization should be avoided (or delayed) in P. radiata plantations on clear-cut coniferous areas if the risk of H. abietis is high. Our results also indicate a strong genetic variation in H. abietis susceptibility within the Galician P. radiata breeding population. The high family-mean and the moderate individual-tree heritability estimates suggest that improving resistance to this pest by conventional breeding techniques is possible. The use of planting stock with improved resistance should be considered as another prophylactic measure to supplement the traditional methods employed against this pest.


2008 ◽  
Vol 38 (9) ◽  
pp. 2372-2381 ◽  
Author(s):  
S. Kumar ◽  
R. D. Burdon ◽  
G. T. Stovold ◽  
L. D. Gea

Clonal trials of Pinus radiata D. Don (radiata pine), representing two populations (or breeds), one selected for growth and form (GF) and the other selected for high wood density as well as growth and form (HD), were replicated on two low-altitude New Zealand sites: Tarawera (pumice soil, 38°08′S) and Woodhill (coastal dune, 36°42′S). The GF material comprised 33 pair-crosses (19 parents) × 10 clones, and the HD material comprised 19 single-pair crosses (35 parents) × 10 clones, with six ramets per clone per site. Diameter (DBH), two tree-form variables, and needle retention (NRA) were assessed 8 years after planting, and wood density (DEN), acoustic velocity, and collapse were assessed 9 years after planting. The site differences were generally expressed more strongly in the GF population. Estimated genetic parameters were mostly similar for the two breeds, except that genotypic correlation between DBH and DEN was apparently zero in the HD population. Estimated broad-sense heritabilities (H2) were generally markedly higher than narrow-sense heritability estimates (h2), except with DEN. Estimated between-site type-B clonal genotypic correlations were generally high (>0.8) for wood properties. Overall, DBH showed adverse genetic correlations with wood properties. The Elite/Breed strategy appeared to be helpful in combating adverse genetic correlations.


2010 ◽  
Vol 40 (8) ◽  
pp. 1550-1557 ◽  
Author(s):  
Michael S. Watt ◽  
Charles Sorensson ◽  
Dave J. Cown ◽  
Heidi S. Dungey ◽  
Robert Evans

Detailed radial measurements of wood properties, taken at breast height, were obtained from control pollinated seedlings and a selection of 13 year old radiata pine ( Pinus radiata D. Don) clones. Using these data the key objectives of this study were to determine (i) the magnitude of mean clonal variation in modulus of elasticity (MOE) and properties affecting MOE (density and microfibril angle (MFA)) and (ii) whether there is a significant age × clone interaction for these traits. All wood properties were significantly affected by the main and interactive effects of age and clone. There was a relatively linear increase in both MOE and density with tree age, while MFA declined linearly with tree age. Values of density and MOE diverged between the clonal extremes from age 3 to age 12. After diverging markedly up to age 6, differences in MFA between clonal extremes remained relatively constant to age 12. At age 12, values for density, MFA, and MOE varied between clonal extremes by, respectively, 194 kg·m–3 (465–659 kg·m–3), 11.3° (9.6–20.9°), and 11.2 GPa (10.4–21.6 GPa). The seedling material had a relatively intermediate ranking, across the age range, for all traits considered.


2007 ◽  
Vol 37 (1) ◽  
pp. 116-127 ◽  
Author(s):  
Washington Gapare ◽  
Adrian Hathorn ◽  
Dominic Kain ◽  
Colin Matheson ◽  
Harry Wu

Spiral grain is the angular arrangement of fibres in a tangential plane with reference to the pith or vertical tree axis. Spiral grain angles exceeding 5° can cause wood to twist, which may result in a considerable amount of waste and degrade. We assessed spiral grain at breast height in two related progeny tests of radiata pine (Pinus radiata D. Don) aged 8 and 9 years established at two different sites in Australia. Radial trends for grain angle at the two sites were similar. Mean spiral grain (MSG) across the two trials was 4.3° with a standard deviation of 1.5° and a range of 0.8–10°. Estimates of individual tree heritabilities on a single-site basis for individual rings and MSG suggested that spiral grain is lowly to highly inherited (h2 = 0.11 ± 0.08 to 0.66 ± 0.21 for individual rings and 0.44 ± 0.12 for MSG). Additive genotypic correlations between individual rings grain angle and MSG were generally high, above 0.71, suggesting a favourable expected correlated response of mean grain angle in the juvenile wood to selection for grain angle of individual rings. Selection to reduce spiral grain on any of rings 2–4 (at a selection intensity of 1.755, i.e., selecting the best 10% of trees) would result in a predicted correlated genetic gain in MSG of 1.0°. Our results suggest that selection could be performed in any of the individual rings 2, 3, or 4 (equivalent to ages 4–6) and still achieve at least 75% of the genetic gain possible from selection on the mean of all rings 1–5 (MSG). This suggests that there is an optimum stage (rings 2–4) in which selection for this trait should take place. Our results suggest that a reduction in spiral grain angle in the juvenile core is one strategy to reduce the amount of lower grade timber owing to twist.


2015 ◽  
Vol 49 (6) ◽  
pp. 1239-1250 ◽  
Author(s):  
M. Sharma ◽  
M. Brennan ◽  
S. S. Chauhan ◽  
K. M. Entwistle ◽  
C. M. Altaner ◽  
...  

2011 ◽  
Vol 108 (6) ◽  
pp. 1155-1178 ◽  
Author(s):  
M. Paulina Fernández ◽  
Aldo Norero ◽  
Jorge R. Vera ◽  
Eduardo Pérez

2007 ◽  
Vol 37 (11) ◽  
pp. 2164-2174 ◽  
Author(s):  
Brian S. Baltunis ◽  
Harry X. Wu ◽  
Mike B. Powell

A total of 1640 increment cores from 343 radiata pine ( Pinus radiata D. Don) families were sampled at two second-generation progeny trials, aged 6 and 7 years, for a detailed genetic study of juvenile wood quality traits. Density, microfibril angle (MFA), and modulus of elasticity (MOE) were determined from pith to bark using SilviScan® technology. Heritability was greatest for area-weighted density at the two sites (0.63 and 0.77, respectively), and the lowest for growth traits (<0.23). Genotype by environment interaction was low for all three wood quality traits. A positive genetic correlation between density and MOE (0.43), and a highly negative, and therefore, favourable genetic correlation between MFA and MOE (–0.92) were observed, implying that improvement of multiple juvenile wood properties is possible. The genetic correlations between whole-core wood quality traits and individual-ring measurements suggest that improvement for juvenile wood properties across the entire profile of the corewood including the innermost rings can be achieved. However, density, MFA, and MOE had unfavourable genetic correlations with diameter growth suggesting that selection for increased density and MOE, and reduced MFA in the absence of selection for growth will result in a genetic loss for growth rate.


IAWA Journal ◽  
2009 ◽  
Vol 30 (2) ◽  
pp. 189-198 ◽  
Author(s):  
Hema Nair ◽  
Brian Butterfield ◽  
Sandra Jackson

Pinus radiata D. Don (radiata pine) wood can develop a wood quality defect called ‘intra-ring checking’ (checks) during kiln drying. A study was conducted to examine if rays and resin canals were the initiation sites of checks, and if the presence of the rays and resin canals increased the susceptibility of radiata pine wood to checking. The structural features associated with checking were observed in images of thirteen oven-dried radiata pine disks. Six of the sixty checks observed were associated with rays and resin canals. It is clear from the observations that rays and resin canals could not be the primary sites for check development. A comparative study showed some differences between the checked and non-checked wood with respect to rays and resin canals. Checked wood showed a higher amount of tissue area occupied by rays than the nonchecked wood. Hence, it is possible that rays can influence the tendency of wood to check. Such a relationship was not seen with respect to resin canals. However, a difference in the arrangement of resin canals was observed between checked and non-checked wood. Checked wood showed a scattered arrangement of resin canals, while the non-checked wood showed a linear arrangement.


2015 ◽  
Vol 39 (4) ◽  
pp. 751-758 ◽  
Author(s):  
Jerome Alteyrac

ABSTRACTFour stands of 28-year-old radiata pine (Pinus radiata D. Don) grown in the eighth region (Biobio) of Chile were sampled to determine the effect of tree spacing on the microfibril angle. The samples were taken at two different stem levels of the tree, 2.5 m and 7.5 m, with increment strip taken in the Nothern direction. The four experimental stands were characterized by the following spacing 2x2, 2x3, 3x4 and 4x4. The microfibril angle was measured by X-ray diffraction with the SilviScan technology at the FP-Innovation-Paprican Division in Vancouver, Canada. The results showed a significant effect of tree spacing on the microfibril angle in both juvenile wood and mature wood as well as at the two stem levels considered. The minimum (9.42º) was reached in 2x2 stand at 7.5 m in mature wood, while maximum microfibril angle (24.54º) was obtained in 2x3 stand at 2.5 m in juvenile wood. Regarding the effect of tree spacing, 4x4 stand had the lowest microfibril angle,except in mature wood at 7.5 m where 4x4 had the highest microfibril angle (11°) of the four stands.


2004 ◽  
Vol 28 (4) ◽  
pp. 196-204 ◽  
Author(s):  
Jennifer H. Myszewski ◽  
Floyd E. Bridgwater ◽  
William J. Lowe ◽  
Thomas D. Byram ◽  
Robert A. Megraw

Abstract In recent years, several studies have examined the effect of microfibril angle (MFA) on wood quality. However, little research has been conducted upon the genetic mechanisms controlling MFA. In this study, we examined the heritability of MFA in loblolly pine, Pinus taeda L.,and its genetic relationships with height, diameter, volume, and specific gravity. Increment cores were collected at breast height from 20 to 25 progeny from each of 12 to 17 crosses (among 11 parents) in two modified partial-diallels in different locations in southern Arkansas. Specific gravitywas measured on segments containing rings 1 through 5 and on segments containing rings 6 through 20. MFA was measured on the earlywood and latewood sections of rings 4, 5, 19, and 20. Rings 4 and 5 were chosen as representative of core wood and rings 19 and 20 as representative of outer wood. Analyses of variance revealed statistically significant genetic and environmental influences on MFA. Significant general combining ability (GCA), specific combining ability (SCA), and SCA × block effects indicated that there are both additive and nonadditive genetic influences on MFA. Individual-tree, narrow-sense heritability estimates were variable, ranging from 0.17 for earlywood (ring) 4 MFA to 0.51 for earlywood (ring) 20 MFA. Genetic correlations between MFA, specific gravity, and the growth traits were nonsignificant due to large estimated standard errors. South.J. Appl. For. 28(4):196–204.


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