Inheritance of spiral grain in the juvenile core of Pinus radiata

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.

2004 ◽  
Vol 34 (12) ◽  
pp. 2410-2423 ◽  
Author(s):  
S D Carson ◽  
M F Skinner ◽  
A T Lowe ◽  
M O Kimberley

Two intensive harvesting trials with contrasting nutrient capital were examined for genetic × environment interactions to age 5 years after planting. Treatments included differences in removal of organic matter and in site preparation and weed control, with each treatment having both fertilized and nonfertilized plots. Three harvest treatments (both fertilized and nonfertilized) were common to both sites, with two additional treatments at one site. There were four replicate plots of each treatment combination at each site, with two trees from each of three control seed lots and 47 open-pollinated families chosen to represent the range of performance for growth planted in each plot. Large differences among sites and among treatments in both growth and foliar nutrient concentration were observed. Genetic × site interactions and genetic × treatment within site interactions were seldom significant. Significant interactions did not appear to be related to changes in rankings of families, but rather to the differences in variance among families in different treatments. This study suggests that selection of specific radiata pine (Pinus radiata D. Don) families for better growth performance on nutrient-deficient sites in New Zealand would not result in substantial improvement over selection for growth on all sites disregarding nutrient availability.


2001 ◽  
Vol 31 (5) ◽  
pp. 779-785 ◽  
Author(s):  
Satish Kumar ◽  
D J Garrick

Marker-assisted selection (MAS) provides an opportunity to increase the efficiency of within-family selection in forest tree breeding. Within-family MAS involves selection decisions first made on conventional breeding values and quantitative trait loci (QTL) information used for within-family selection. In this study genetic response obtained by using MAS was compared with conventional methods for three options: "full-sib family forestry," "clonal forestry," and "forward selection for deployment." This comparison was undertaken using stochastic simulation for a locus that explained 10 or 20% of the genetic variance. In the full-sib family forestry scenario, markers were used to select genotypes (among juvenile individuals in a family) for vegetative propagation. Markers were used to preselect genotypes for clonal testing in clonal forestry option. In case of forward selection for deployment option, offspring that have favourable marker haplotype and a superior phenotype were selected from each family. The comparison between the MAS and the conventional strategy was evaluated in genetic terms based on comparison of the average genetic merit of the genotypes used for deployment in production plantations. The relative genetic gain (%) using MAS were found to be 4–8% and 2–3% higher compared with conventional strategy for full-sib family forestry and clonal forestry options, respectively. In case of forward selection for deployment option, MAS was generally found to be providing higher genetic gain only when the heritability is low.


1999 ◽  
Vol 29 (12) ◽  
pp. 1958-1965 ◽  
Author(s):  
E Guilley ◽  
M Loubère ◽  
G Nepveu

Grain angle on bark (angle between the general direction of bark fissures and the axis of the trunk) was assessed at the four cardinal points at breast height (1.3 m) on 82 standing sessile oaks (Quercus petraea Liebl.). After felling, wood spiral grain was measured at breast height from cambium to pith along two diametrically opposite radii. A mixed-effect model that links the tangent of grain angle to radial position (age and distance from the pith) allows to estimate two individual parameters of grain angle. In the field, nondestructive measurements of grain angle (subcortical spiral grain or spiral grain on bark) on an individual tree combined with information on the tree stand allow to estimate one of the two parameters that describes the change in grain angle for a given radial increment. This parameter is independent of mean ring width, tree age and circumference, and site characteristics; it should allow a more accurate identification and selection of standing trees with low wood spiral grain.


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).


2006 ◽  
Vol 55 (1-6) ◽  
pp. 77-84 ◽  
Author(s):  
S. Kumar ◽  
H. S. Dungey ◽  
A. C. Matheson

Abstract The two main objectives of this study were: (1) to determine how early is it possible to undertake selection to improve the stiffness of corewood; (2) to determine if the selection based on corewood stiffness could also improve outerwood stiffness, and vice versa. Breastheight data from two progeny trials of Pinus radiata D. Don were used. In the first trial (age 30 years), data on Silviscan predicted stiffness (MoE) was obtained for each growth ring on each core sample from 50 open-pollinated families. In the second trial (age 14 years), data on static-bending MoE was obtained using clearwood sticks (300 × 20 × 20 mm) cut from each tree from 18 control-pollinated families. MoE varied from 3.5 GPa in rings 1-5 to about 17 GPa in rings 21-25. Coefficients of variation of corewood and outerwood MoE were about 20-30% and 15-20% respectively. Estimates of narrowsense heritability for MoE were generally higher (0.50-0.70) in the corewood compared with the outerwood (0.15-0.30). Early selection for MoE could yield substantial gain in corewood MoE but only small gains, if any, in outerwood MoE (especially for rings 21-30). Estimated genetic correlations between density and stiffness appeared moderate in the corewood zone, but high in the outerwood zone. Selection based on density (using 5-mm cores) and acoustic stiffness (using standing tree tools), assessed at age 6-7 years, appeared to be a good option to improve both corewood and outerwood stiffness.


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.


1998 ◽  
Vol 66 (3) ◽  
pp. 751-757 ◽  
Author(s):  
B. Tufvesson ◽  
M. Tufvesson ◽  
K. Johansson ◽  
M. Wilhelmson

AbstractHyaluronic acid (HA) is a polysaccharide preferably extracted from cockerel combs and used for medical purposes, mainly eye surgery. One way of increasing the production of HA from cockerels is to increase the size of the combs. The aim of this work was to study comb development and quantify direct and correlated responses for comb size at different ages and comb weight in two lines of White Leghorn selected for comb size at two different ages. Two lines were created, one selected for comb size at 16 weeks of age (CS16) (line E = early comb development) and the other for comb size at 29 weeks of age (CS29) (line A = adult comb size). There were between 500 and 800 birds of each line and generation and the lines had been selected for five generations. Cockerels in line E developed the combs at an earlier age and had smaller 29-week combs compared with the cockerels in line A. Genetic gain for the selection trait in generation five, measured in relation to line means in generation 1, was 58% in line E and 36% in line A. The corresponding correlated response for CS29 and comb weight (CW) in line E was 28% and 25% respectively, while for CS16 and CW in line A it was 46% and 35%. The results indicated that it is possible to increase cockerel comb size at both 16 and 29 weeks of age through selection.


2013 ◽  
Vol 43 (1) ◽  
pp. 12 ◽  
Author(s):  
Michael S Watt ◽  
Mark O Kimberley ◽  
Jonathan J Harrington ◽  
Mark JC Riddell ◽  
Dave J Cown ◽  
...  

1974 ◽  
Vol 19 (1) ◽  
pp. 33-45 ◽  
Author(s):  
P. A. Forrest ◽  
Maurice Bichard

SUMMARYPhenotypic and genetic parameters for reproductive performance in a flock of Clun Forest ewes have been estimated. Average litter size (ALS) appeared to be more repeatable than the number of lambs born per ewe mated and present at lambing (NLBEM), and the estimates obtained by regression (0·15 and 0·14) were slightly higher than those from the analyses of variance (0·12 and 0·09). The repeatability of barrenness was very low (0·05). It was concluded that little scope existed for the improvement of reproductive performance from a regular policy of culling.Estimates of heritability by analysis of variance and a method for all-or-none traits were 0·12 and 0·11 for ALS, and 0·15 and 0·10 for NLBEM, whereas barrenness was less heritable (0·07). An estimate of 016 was found for the heritability of ALS performance over two years. The phenotypic correlation between body weight and reproductive performance were positive yet small (ALS:+0·16; NLBEM:+0·10), while at the genetic level ALS was more strongly related to body weight (+0·21) than NLBEM (-0·04). The genetic regressions indicated that an increase of 5 lambs per 100 ewes lambing would accompany genetic gain of 5 kg in ewe body weight, while an increase of 1 lamb per ewe lambing would lead to a correlated response in body weight of 5 kg.Selection for ALS on the basis of dams' performance, within the flock studied, would be expected to yield a rate of progress of 2% per annum.


Sign in / Sign up

Export Citation Format

Share Document