Genetic parameters for spiral grain in two 18-year-old progeny trials with Sitka spruce in Denmark

1998 ◽  
Vol 28 (6) ◽  
pp. 920-931 ◽  
Author(s):  
Jon Kehlet Hansen ◽  
Hans Roulund
Keyword(s):  
Genetic Correlations ◽  
Sitka Spruce ◽  
Diameter Growth ◽  
Environment Interaction ◽  
Stem Form ◽  
Narrow Sense Heritability ◽  
Spiral Grain ◽  
Stem Straightness ◽  
The Mean ◽  
The Individual

The spiral grain at ring 10 at 1.3 m was investigated in two trials with 64 open-pollinated families of age 18 years from plus-trees of Sitka spruce (Piceasitchensis (Bong.) Carr.) selected from 16 populations. Significant differences were found between the families on both sites, and the individual narrow-sense heritability of the spiral grain was 0.63 and 0.78, assuming half-sib families. The mean spiral grain was 3.8 and 4.1° to the left in the two trials and the individual standard deviations 1.86 and 1.62°. No signs of genotype– environment interaction was found. Genetic correlations with diameter growth, stem form, and pilodyn were not apparent in the trials. Reductions of the mean spiral grain by 0.5–1° in the juvenile wood seems possible even with simultaneous gains for stem straightness and diameter growth, either from selections among plus-trees grafted in a clonal seed orchard or from the progenies in the trials.

The genetic variation in the timing of heteroblastic transition in Eucalyptus globulus is stable across environments

2011 ◽  
Vol 59 (2) ◽  
pp. 170 ◽  
Author(s):  
M. G. Hamilton ◽  
P. A. Tilyard ◽  
D. R. Williams ◽  
R. E. Vaillancourt ◽  
T. J. Wardlaw ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Phase Change ◽  
Eucalyptus Globulus ◽  
Developmental Change ◽  
Genetic Correlations ◽  
Genotype By Environment Interaction ◽  
Environment Interaction ◽  
Narrow Sense Heritability ◽  
Genotype By Environment ◽  
Analyse Data

Eucalyptus globulus is one of the best known examples of a heteroblastic plant. It exhibits a dramatic phase change from distinctive juvenile to adult leaves, but the timing of this transition varies markedly. We examined the genetic variation in the timing of heteroblastic transition using five large open-pollinated progeny trials established in north-western Tasmania. We used univariate and multi-variate mixed models to analyse data on the presence/absence of adult or intermediate foliage at age 2 years from a total of 14 860 trees across five trials, as well as height to heteroblastic phase change from one trial. Up to 566 families and 15 geographic subraces of E. globulus were represented in the trials. The timing of the heteroblastic transition was genetically variable and under strong genetic control at the subrace and within-subrace level, with single-trial narrow-sense heritability estimates for the binary trait averaging 0.50 (range 0.44–0.65). The degree of quantitative trait differentiation in the timing of heteroblastic transition among subraces, as measured by QST, exceeded the published level of neutral molecular marker (FST) differentiation in all cases, arguing that diversifying selection has contributed to shaping broad-scale patterns of genetic differentiation. Most inter-trial genetic correlations were close to one at the subrace and additive genetic levels, indicating that the genetic variation in this important developmental change is expressed in a stable manner and that genotype-by-environment interaction is minimal across the environments studied.

Heartwood production in a 35-year-old black walnut progeny test

2002 ◽  
Vol 32 (1) ◽  
pp. 177-181 ◽  
Author(s):  
K E Woeste
Keyword(s):  
Cross Section ◽  
Genetic Correlations ◽  
Ground Level ◽  
Black Walnut ◽  
Progeny Test ◽  
Diameter Growth ◽  
Heartwood Formation ◽  
Narrow Sense Heritability ◽  
Above Ground Level ◽  
Percent Area

A 35-year-old black walnut (Juglans nigra L.) progeny test was evaluated for growth and production of heartwood. The test trees, which were open-pollinated progeny of select females in seven states, were planted on a good-quality, uniform site in Wabash County, central Indiana, U.S.A. Increment cores were used to estimate the amount of heartwood at 1.3 m above ground level. There were significant differences among open-pollinated families (α = 0.10) for both area of heartwood and percent area of heartwood. Narrow-sense heritability estimates for these traits were moderate (0.40 and 0.27), indicating opportunity for gain from selection. Faster growing trees had more heartwood and a higher percentage of heartwood area in cross section. Genetic correlations indicated that the rate and amount of heartwood formation is closely related to diameter growth.

Genetic improvement of early vigour in wheat

1999 ◽  
Vol 50 (3) ◽  
pp. 291 ◽  
Author(s):  
G. J. Rebetzke ◽  
R. A. Richards
Keyword(s):  
Genetic Variation ◽  
Leaf Area ◽  
Plant Biomass ◽  
Genetic Correlations ◽  
Yield Potential ◽  
Environment Interaction ◽  
Narrow Sense Heritability ◽  
Wheat Varieties ◽  
Early Vigour ◽  
Selection For

Grain yield potential of Australian wheat crops is often limited because of inadequate water for crop growth and grain filling. Greater early vigour, defined here as the amount of leaf area produced early in the season, should improve the water-use efficiency and yield of wheat crops grown in Mediterranean-type climates such as occurs in southern Australia. In order to maximise selection efficiency for early vigour in breeding programs, the magnitude and form of genetic variation for early vigour and its components was investigated for 2 contrasting wheat populations. The first population comprised 28 Australian and overseas wheat varieties evaluated in a serial sowing study in Canberra. The second population contained 50 random F 2:4 and F 2:6 families derived from a convergent cross of elite CIMMYT wheat lines evaluated in Canberra, and in the field at Condobolin, New South Wales. For the first population, environmental effects on leaf breadth and length, and to a lesser extent, phyllochron interval, produced significant (P < 0.05) changes in leaf area. Large and significant (P < 0.05) differences were observed among Australian and overseas wheats for early vigour and its components. Australian varieties were among the least vigorous of the lines tested, with a number of overseas varieties producing about 75% greater leaf area than representative Australian wheats. Increased leaf area was genetically correlated with increases in leaf breadth and length, and a longer phyllochron interval. Significant (P < 0.05) genotype ´ environment interaction reduced broad-sense heritability (%) for early vigour (H ± s.e., 87 ± 26) compared with leaf breadth (96 ± 25) and length (97 ± 27). Narrow-sense heritability (%) in the second population was small for leaf area (h2 ± s.e., 30 ± 6) and plant biomass (35 ± 7), but high for leaf breadth (76 ± 14) and length (67 ± 16). Genetic correlations were strong and positive for leaf area with plant biomass, leaf breadth and length, specific leaf area and coleoptile tiller frequency, whereas faster leaf and primary tiller production were negatively correlated with leaf area. The high heritability for leaf breadth coupled with its strong genetic correlation with leaf area (rg = 0.56-0.57) indicated that selection for leaf breadth should produce genetic gain in leaf area similar to selection for leaf area per se. However, the ease with which leaf breadth can be measured indicates that selection for this character either by itself, or in combination with coleoptile tiller production, should provide a rapid and non-destructive screening for early vigour in segregating wheat populations. The availability of genetic variation for early vigour and correlated traits should enable direct or indirect selection for greater leaf area in segregating wheat populations.

Response to selection in Australian Merino sheep. VIII.* Further results on selection for high clean wool weight with attention to quality

1978 ◽  
Vol 29 (3) ◽  
pp. 615 ◽  
Author(s):  
HN Turner ◽  
N Jackson
Keyword(s):  
Genetic Correlations ◽  
Fibre Diameter ◽  
Control Group ◽  
Environment Interaction ◽  
Genetic Progress ◽  
Weight One ◽  
The Mean ◽  
Selection For ◽  
Made In ◽  
Australian Merino

Results of selection for high clean wool weight per head with control of quality are reported for two selection groups over the period 1966–74. Results for the same experiment for the periods 1950–1959 and 1961–64 were reported earlier. Both groups were selected for high clean wool weight, one (S) with a ceiling on fibre diameter and degree of skin wrinkle, and the other (MS) with a lower limit on staple crimp frequency and a ceiling on skin wrinkle. Genetic progress in clean wool weight was greater in S than in MS over the 1966–74 period (0.12–0.15 lb/annum, compared with 0.06–0.09). This was to be expected from genetic correlations of clean wool weight with fibre diameter (low positive) and staple crimp frequency (high negative). The result supports the previous recommendation that staple crimp frequency is an inefficient way of controlling wool quality while attempting to improve quantity by selection, because its use severely restricts the likely progress in quantity. The actual rate of progress in the S group was similar to that in the period 1950–59, which was followed by a fall in superiority of the selected over the control group animals born during 1961–64. The recovery of response in the 1966–74 period negates the suggestion that the loss of response during the 1961-64 period was due to a 'plateau'. The most likely explanation is that a genotype x environment interaction occurred, such that the genetic gain made in the 1950-59 period could not be expressed in the poorer environments of 1960–65, but reappeared gradually under the improving environment of the 1966–74 period. Attempts to remove this interaction by regression of response on the mean clean wool weight of the unselected control group (as an index of the level of the environment) for each year, were not successful. The interaction is, therefore, not simply a case of all selection groups being equal when the environment is poor. ________________ *Part VII, Aust. J. Agric. Res., 26: 937 (1975).

Heritability and combining ability of vegetative and phenological characters of winged beans (Psophocarpus tetragonolobus (L.) D.C.)

1981 ◽  
Vol 96 (3) ◽  
pp. 503-508 ◽  
Author(s):  
W. Erskine
Keyword(s):  
Leaf Size ◽  
Diallel Cross ◽  
Environment Interaction ◽  
Psophocarpus Tetragonolobus ◽  
Narrow Sense Heritability ◽  
Area Index ◽  
Hybrid Combination ◽  
Number Of Leaves ◽  
The Mean

SUMMARYThe variability generated in a diallel cross between seven genotypes for vegetative and phenological characters was studied in the F1 and F2 generations in lowland Papua New Guinea. The mean narrow-sense heritability values of mean leaf size and leaf area index at flowering were 88·0 and 78·5%. The parental values of these characters gave good predictability of the performance of the parents in hybrid combination. For mean number of leaves per plant at flowering, environmental effects were of major importance, and consequently selection between crosses for number of leaves is considered futile. There was a large genotype ˣ environment interaction for time to first flower. The role of various environmental factors in causing the interaction for flowering is discussed.

scholarly journals Evolution of genetic variability in a spatially heterogeneous environment: effects of genotype–environment interaction

1987 ◽  
Vol 49 (2) ◽  
pp. 147-156 ◽  
Author(s):  
Sara Via ◽  
Russell Lande
Keyword(s):  
Genetic Variability ◽  
Genetic Correlation ◽  
Genetic Variance ◽  
Genetic Correlations ◽  
Covariance Structure ◽  
Genetic Models ◽  
Quantitative Character ◽  
Disruptive Selection ◽  
Environment Interaction ◽  
The Mean

SummaryClassical population genetic models show that disruptive selection in a spatially variable environment can maintain genetic variation. We present quantitative genetic models for the effects of disruptive selection between environments on the genetic covariance structure of a polygenic trait. Our models suggest that disruptive selection usually does not alter the equilibrium genetic variance, although transient changes are predicted. We view a quantitative character as a set of character states, each expressed in one environment. The genetic correlation between character states expressed in different environments strongly affects the evolution of the genetic variability. (1) If the genetic correlation between character states is not ± 1, then the mean phenotype expressed in each environment will eventually attain the optimum value for that environment; this is the evolution of phenotypic plasticity (Via & Lande, 1985). At the joint phenotypic optimum, there is no disruptive selection between environments and thus no increase in the equilibrium genetic variability over that maintained by a balance between mutation and stabilizing selection within each environment. (2) If, however, the genetic correlation between character states is ± 1, the mean phenotype will not evolve to the joint phenotypic optimum and a persistent force of disruptive selection between environments will increase the equilibrium genetic variance. (3) Numerical analyses of the dynamic equations indicate that the mean phenotype can usually be perturbed several phenotypic standard deviations from the optimum without producing transient changes of more than a few per cent in the genetic variances or correlations. It may thus be reasonable to assume a roughly constant covariance structure during phenotypic evolution unless genetic correlations among character states are extremely high or populations are frequently perturbed. (4) Transient changes in the genetic correlations between character states resulting from disruptive selection act to constrain the evolution of the mean phenotype rather than to facilitate it.

Genetic Variation in Acoustic Time of Flight and Drill Resistance of Juvenile Wood in a Large Loblolly Pine Breeding Population

2019 ◽  
Vol 65 (4) ◽  
pp. 469-482 ◽  
Author(s):  
Trevor D Walker ◽  
Fikret Isik ◽  
Steven E McKeand
Keyword(s):  
Specific Gravity ◽  
Loblolly Pine ◽  
Wood Quality ◽  
Genetic Correlations ◽  
Time Of Flight ◽  
Phenotypic Correlation ◽  
Environment Interaction ◽  
Quality Traits ◽  
Economic Traits ◽  
Stem Straightness

AbstractAcoustic time of flight and drill resistance (surrogates for wood stiffness and density, respectively) were measured on 11,097 standing trees from 269 pollen-mix families of loblolly pine (Pinus taeda L.) in 6- to 9-year-old progeny tests at eight sites across the southeastern United States. Specific gravity was measured on two test sites. The phenotypic correlation between specific gravity and drill resistance was moderate (r = 0.68), whereas the genetic correlation was very strong (rg = 0.96). Narrow-sense heritabilities for acoustic time of flight and drill resistance were around 0.35 for individual trees and very strong (0.90) for family means. High genetic correlations (&gt;0.80) between pairs of sites suggested a low genotype-by-environment interaction for both traits. Genetic correlations between wood quality traits and other economic traits (growth and stem straightness) were low except for a moderate correlation between acoustic time of flight and tree slenderness (rg = –0.64). The checklot ranked near the middle for both wood quality traits, implying no inadvertent selection occurred in this population that has been selected intensively for volume productivity. This study is the first to apply these tools in a large breeding program, and results suggest they are effective for selecting genotypes for wood quality.

Spiral grain in a clonal trial with Sitka spruce

1998 ◽  
Vol 28 (6) ◽  
pp. 911-919 ◽  
Author(s):  
Jon Kehlet Hansen ◽  
Hans Roulund
Keyword(s):  
Standard Deviation ◽  
Compression Wood ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Spiral Grain ◽  
Compass Direction ◽  
Phenotypic Standard Deviation ◽  
The Mean ◽  
Clonal Trial ◽  
Residual Variances

Grain angles to the left in seven clones of Sitka spruce (Picea sitchensis (Bong.) Carr.) decreased from the pith and outwards and with height. Effects of compression wood and compass directions were non-significant. Clones differed significantly but interacted with height levels, ring numbers, compass direction, and compression wood. However, the interaction with compression wood was small. Furthermore, some interaction with compass direction could possibly be attributed to eccentric stems and stem axis choice. The repeatability was 72% for averages of ramets measured in five height levels and most rings from the pith. The mean spiral grain was 2.2°, and the phenotypic standard deviation between averages of ramets was 1.07°. Genetic gains of 1° from phenotypic selections based on several measurements were suggested using these values. Variations between ramets and residual variances accounted for most of the variation. Thus, as many ramets as possible should be sampled to obtain the best estimates of mean clonal levels. Clone interactions with height levels and ring numbers from the pith were less important. This was also explained by correlations of 0.83–0.98 among clone averages at 1.3 m for single rings and overall clone means. Only significant effects ring widths were present within clones.

Genetic variation in the diameter–height relationship in Scots pine (Pinus sylvestris)

2008 ◽  
Vol 38 (6) ◽  
pp. 1493-1503 ◽  
Author(s):  
Johan Kroon ◽  
Bengt Andersson ◽  
Tim J. Mullin
Keyword(s):  
Pinus Sylvestris ◽  
Scots Pine ◽  
Genetic Correlations ◽  
Tree Height ◽  
Phenotypic Variance ◽  
Stem Form ◽  
Narrow Sense Heritability ◽  
Growth Selection ◽  
Microsite Heterogeneity ◽  
Adjusted Model

Genetic parameters were estimated for the diameter–height (d-h) relationship and three other tree stem-form characteristics (total height, breast height diameter, and total tree volume) for data from 10 diallel progeny trials of Scots pine ( Pinus sylvestris L.), at about 30 years of age in Sweden. Linear mixed models were fit to the data, where adjustments for intertree competition and microsite heterogeneity were made by means of covariates in a nearest-neighbour analysis. The d-h relationship was analyzed with a covariate (tree height) adjusted model of diameter. Average estimates of the additive coefficient of variation and narrow-sense heritability for the d-h relationship were 7.4% and 0.22, respectively. Estimates of dominance were comparatively small (average dominance: phenotypic variance ratio of 0.04). The results indicate that there is scope to modify the d-h relationship by selection and breeding. Additive genetic correlations between the d-h relationship and height were negative, with a mean of –0.62. Selection for height would thus result in stems that are more slender than average, suggesting that tall trees allocate relatively more resources to height growth than to diameter growth. Selection based on height alone will negatively affect volume gain.

scholarly journals Growth Performance and Heritability Estimation of Acacia crassicarpa in a Progeny Trial in eastern Thailand

2016 ◽  
Vol 65 (2) ◽  
pp. 58-64 ◽  
Author(s):  
Uraiwan Hanchor ◽  
Somporn Maelim ◽  
Wathinee Suanpaga ◽  
Ji-Min Park ◽  
Kyu-Suk Kang
Keyword(s):  
Growth Performance ◽  
Block Design ◽  
Characteristic Analysis ◽  
Stem Form ◽  
Narrow Sense Heritability ◽  
Progeny Trial ◽  
Individual Volume ◽  
Heritability Estimation ◽  
Stem Straightness ◽  
Acacia Crassicarpa

Abstract Growth performance and heritability were studied in a progeny trial of Acacia crassicarpa in Chacheongsao province, eastern Thailand in order to provide information on suitable families for seed improvement and production. A randomized complete block design (originally 8 blocks, 80 family plots/block, 4 trees/plot) of the best 80 half-sib families selected from 7 provenances was thinned at ages 2.5, 4 and 5 years based on growth and tree form and so that there was one tree/plot remained at the stage of present study. All remaining trees were measured for diameter at breast height (DBH), tree height (H), individual volume (VOL) and stem form (straightness and forked height) at ages 12, 12.5, 13 and 13.5 years, respectively. Narrow sense heritability (h2) based on family was estimated for each characteristic. Analysis of variance showed that there were highly significant differences among families at the four ages for DBH, H and VOL. Stem straightness and forked height were not significantly different among families. The heritability of DBH was increased as trees were mature (h2 = 0.236, 0.285, 0.288, and 0.291) but those of H and VOL were a little decreased. The heritability of stem straightness was very low (0.013) and that of forked height was also low (0.138). The results implied that the tree breeding of A. crassicarpa could improve DBH, H and VOL considerably. Further selection testing is required to increase the heritability of stem form. The measured data would be useful for tree improvement and seed orchard establishment of Acacia crassicarpa.

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