scholarly journals Estimates of genetic parameters for oleoresin and growth traits in juvenile loblolly pine

2003 ◽  
Vol 33 (12) ◽  
pp. 2469-2476 ◽  
Author(s):  
James H Roberds ◽  
Brian L Strom ◽  
Fred P Hain ◽  
David P Gwaze ◽  
Steven E McKeand ◽  
...  
Keyword(s):  
Loblolly Pine ◽  
Growth Traits ◽  
Genetic Correlations ◽  
The United States ◽  
Dendroctonus Frontalis ◽  
Resin Flow ◽  
Narrow Sense Heritability ◽  
Diallel Mating Design ◽  
Santa Rosa County ◽  
Old Trees

In southern pines of the United States, resistance to attack by southern pine beetle, Dendroctonus frontalis Zimmermann, is believed to principally involve flow of oleoresin to beetle attack sites. Both environmental and genetic factors are known to affect the quantity of oleoresin flow in loblolly pine, Pinus taeda L., but little is known about the genetic contribution to phenotypic variation in this trait. Here we report estimates of genetic variation in oleoresin flow and growth traits for a population of this species. Oleoresin yield, total height, and diameter were measured on 10- and 11-year-old trees from an experimental test in Santa Rosa County, Florida. Trees were from 72 full-sib families produced by mating 48 parents according to a disconnected partial diallel mating design. Resin yield was determined from breast-height samples collected at two times: once in the summer of 1999 when latewood was being produced (summer resin flow), and once in the spring of 2000 during earlywood formation (spring resin flow). All traits studied were found to be highly genetically variable and to have much greater additive than dominance variance. Estimates of narrow-sense heritability for spring and summer resin flow were in the moderate range and are comparable to values obtained for the growth traits. Additive genetic correlations between oleoresin yield and the growth traits were positive and moderately high, suggesting that directional selection to improve growth in loblolly pine will also result in increased production of oleoresin.

scholarly journals Genetic Variation in the Microfibril Angle of Loblolly Pine From Two Test Sites

2004 ◽  
Vol 28 (4) ◽  
pp. 196-204 ◽  
Author(s):  
Jennifer H. Myszewski ◽  
Floyd E. Bridgwater ◽  
William J. Lowe ◽  
Thomas D. Byram ◽  
Robert A. Megraw
Keyword(s):  
Specific Gravity ◽  
Loblolly Pine ◽  
Combining Ability ◽  
Growth Traits ◽  
Genetic Relationships ◽  
Wood Quality ◽  
Genetic Correlations ◽  
Microfibril Angle ◽  
Narrow Sense Heritability ◽  
Individual Tree

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.

Breeding for improved growth and juvenile corewood stiffness in slash pine

2007 ◽  
Vol 37 (10) ◽  
pp. 1886-1893 ◽  
Author(s):  
Xiaobo Li ◽  
Dudley A. Huber ◽  
Gregory L. Powell ◽  
Timothy L. White ◽  
Gary F. Peter
Keyword(s):  
Genetic Correlation ◽  
Growth Traits ◽  
Low Cost ◽  
Genetic Correlations ◽  
Volume Growth ◽  
Pinus Elliottii ◽  
Tree Improvement ◽  
Slash Pine ◽  
Narrow Sense Heritability ◽  
Improvement Programs

The importance of integrating measures of juvenile corewood mechanical properties, modulus of elasticity in particular, with growth and disease resistance in tree improvement programs has increased. We investigated the utility of in-tree velocity stiffness measurements to estimate the genetic control of corewood stiffness and to select for trees with superior growth and stiffness in a progeny trial of 139 families of slash pine, Pinus elliottii Engelm. grown on six sites. Narrow-sense heritability estimates across all six sites for in-tree acoustic velocity stiffness at 8 years (0.42) were higher than observed for height (0.36) and diameter at breast height (DBH) (0.28) at 5 years. The overall type B genetic correlation across sites for velocity stiffness was 0.68, comparable to those found for DBH and volume growth, indicating that family rankings were moderately repeatable across all sites for these traits. No significant genetic correlations were observed between velocity stiffness, DBH, and volume growth. In contrast, a significant, but small, favorable genetic correlation was found between height and velocity stiffness. Twenty percent of the families had positive breeding values for both velocity stiffness and growth. The low cost, high heritability and nearly independent segregation of the genes involved with in-tree velocity stiffness and growth traits indicate that acoustic methods can be integrated into tree improvement programs to breed for improved corewood stiffness along with growth in slash pine.

Growth and wood properties of genetically improved loblolly pine: propagation type comparison and genetic parameters

2014 ◽  
Vol 44 (3) ◽  
pp. 263-272 ◽  
Author(s):  
Finto Antony ◽  
Laurence R. Schimleck ◽  
Lewis Jordan ◽  
Benjamin Hornsby ◽  
Joseph Dahlen ◽  
...  
Keyword(s):  
Wood Density ◽  
Loblolly Pine ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Tree Height ◽  
Wood Properties ◽  
Genetically Improved ◽  
Growth Properties ◽  
Wood Traits ◽  
Clonal Lines

The use of clonal varieties in forestry offers great potential to improve growth traits (quantity) and wood properties (quality) of loblolly pine (Pinus taeda L.). Loblolly pine trees established via somatic embryogenesis (clones), full-sib zygotic crosses, and half-sib zygotic open-pollinated families were sampled to identify variation in growth and wood properties among and within clonal lines and zygotic controls. Increment cores 5 mm in diameter were collected at age 4 from a total of 2615 trees. Growth properties (diameter at 1.4 m and total tree height) and wood properties (whole-core density, latewood and earlywood density, and latewood percent) were measured for each tree sampled in the study. Overall, growth properties were better for full-sib seedling than for clonal lines, whereas wood density was higher for clonal lines than full-sib and open-pollinated seedlings. However, there were clonal lines with better growth and higher wood density. Clonal repeatability of both growth and wood properties across sampled sites and genetic correlations between growth and wood traits were determined, with higher repeatability observed for wood traits compared with growth traits. Significant genetic correlations were observed for tree height and wood properties, whereas weak correlations were observed for diameter and wood properties.

Accelerated short-term genetic testing for loblolly pine families

1988 ◽  
Vol 18 (8) ◽  
pp. 1085-1089 ◽  
Author(s):  
Claire G. Williams
Keyword(s):  
Genetic Testing ◽  
Loblolly Pine ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Field Trials ◽  
Day Length ◽  
Short Term ◽  
Test Environment ◽  
Short Term Test ◽  
Extreme Performance

The following experiment was done to test the hypothesis that acceleration of seedling growth increases the juvenile–mature correlation for growth. Growth traits of 18 open-pollinated loblolly pine (Pinustaeda) familes were compared across (i) field trials measured 8 years after planting (mature age), (ii) a short-term test environment with a supplemental incandescent light source (20-h photoperiod) and a higher fertilizer level, and (iii) a short-term test environment with no supplemental day length and a lower fertilizer level. The ranking of two seedlots of known, extreme performance and the juvenile–mature correlations were used as the criteria of early testing success. Juvenile–mature (family mean) correlations were low (r = 0.13) for the growth-accelerating environment relative to the natural day length environment (r = 0.59) and two check seedlots ranked correctly only in the natural day length environment. The genetic correlations between the short-term tests are high for total height [Formula: see text] but lower for height produced after first budset, the trait that has shown value as a juvenile indicator [Formula: see text] The growth-accelerating treatment increases growth per unit time but prompts abnormal shoot development. The nonaccelerating treatment with no supplemental light offered the most promise for genetic testing of 1st-year loblolly pine seedlings.

Loblolly pine responds to mechanical wounding with increased resin flow

1998 ◽  
Vol 28 (4) ◽  
pp. 596-602 ◽  
Author(s):  
Jonathan J Ruel ◽  
Matthew P Ayres ◽  
Peter L Lorio, Jr.
Keyword(s):  
Loblolly Pine ◽  
Bark Beetles ◽  
Defense Mechanism ◽  
Dendroctonus Frontalis ◽  
Resin Flow ◽  
Mechanical Wounding ◽  
Pine Trees ◽  
Plant Defense Mechanism ◽  
Pre Treatment ◽  
Pinus Taeda L

The oleoresin produced by many conifers has a deleterious effect on numerous associated herbivores, including bark beetles (Coleoptera: Scolytidae), and may have evolved as a plant defense mechanism. Three experiments with juvenile loblolly pine (Pinus taeda L.) used mechanical wounding to drain resin reserves and assess the effects of prior bark wounding on subsequent resin flow up to 7 days post-treatment. Resin flow returned to pre-treatment values within 2 days after wounding began and, in nearly every tree in each experiment, continued to increase on subsequent days. On average, resin flow reached double the pre-treatment values (mean ± SE: 2.10 ± 0.10 vs. 1.13 ± 0.10 g/3 h and 2.28 ± 0.09 vs. 0.90 ± 0.09 g/3 h for wounded vs. pre-treatment in experiments 1 and 2, respectively). Considering its timing and magnitude, this previously undescribed response may be important in modulating interactions between pine trees and bark beetles. In addition, resin flow following treatment was greater in trees in larger crown size classes (thinned > edge of stand = unthinned in experiment 1; edge of stand > thinned > unthinned in experiment 2). This may help explain why trees in thinned stands are less susceptible to southern pine beetle (Dendroctonus frontalis Zimm.) infestation than trees in unthinned stands.

scholarly journals 36 Matching cow’s genetics to the environment using genomics

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 34-34
Author(s):  
Jared E Decker ◽  
Troy N Rowan ◽  
Sara Nilson ◽  
Harly J Durbin ◽  
Camila U Braz ◽  
...  
Keyword(s):  
Beef Cattle ◽  
Local Adaptation ◽  
Growth Traits ◽  
Genetic Correlations ◽  
The United States ◽  
Early Summer ◽  
Substitution Effects ◽  
Association Analyses ◽  
Functional Variants ◽  
Genomic Predictions

Abstract Cattle poorly adapted to their environment result in lost revenue and jeopardize the stability of the food supply. Genomic data now allows us to rigorously analyze adaptations and avoid the generation of animals that will not thrive. We used selection scans for local adaptation, genotype-by-environment genome-wide association analyses, creation of hair shedding genomic predictions and environmental region-specific genomic predictions of growth traits to characterize and predict local adaptation in beef cattle. Analyzing ~40,000 cattle from three breed associations with ~850,000 high-accuracy imputed SNPs, we used novel selection mapping methods to identify genomic loci responsible for adaptation. We identify 19 different loci (harboring 24 annotated genes) as responding to selection to local adaptation. In cooperation with 74 producers across the United States, over 12,000 cattle were scored on a scale of 1–5 for the early-summer hair shedding phenotype in 2016, 2017, and 2018. Participating cattle were genotyped using the GGP-F250 SNP panel developed by the University of Missouri, which contains ~170,000 candidate functional variants and ~30,000 variants in common with beef cattle industry standard genotyping assays. Genomic breeding values were generated with a repeated records model using these phenotypes. Further, we identified loci with large allele substitution effects for hair shedding. When local adaptations exist, ranking animals using a regional genetic evaluation will be different from national cattle evaluations. We developed region-specific genomic predictions using a multivariate model in which phenotypes from different regions were fit as separate dependent variables. Genetic correlations between regions were moderate, indicating substantial re-ranking between environmental regions. These genomic predictions will allow rapid identification of cattle best suited to an environment.

scholarly journals Breeding for improved frost-seeded red clover seedling establishment

2006 ◽  
Vol 12 ◽  
pp. 141-144
Author(s):  
Heathcliffe Riday
Keyword(s):  
Trifolium Pratense ◽  
Genetic Correlations ◽  
Red Clover ◽  
Breeding Population ◽  
The United States ◽  
Late Winter ◽  
Seedling Height ◽  
Forage Legume ◽  
Narrow Sense Heritability ◽  
Seedling Performance

In the colder parts of the United States, in late winter after disappearance of snow cover, red clover (Trifolium pratense) is often broadcast seeded into forage legume-depleted grass pastures to increase pasture forage quality. This method of establishment is referred to as frost seeding. However, in an estimated 30-40% of frostseeded pastures in Wisconsin, USA the legumes fail to establish. In this study 40 red clover halfsib families from one breeding population and six check populations were evaluated for spring 2005 establishment by 1) broadcast seeding into existing pasture under frost-seeded conditions and 2) standard drill seeding into 15 cm-spaced rows. In June 2005 seedling counts and heights were measured on halfsib family plots. Narrow sense heritability estimates on a halfsib family basis for seedling stand counts under frost- and drill-seeded establishment were h2 = 0.02 and 0.21 respectively. Heritabilities for seedling height under frost- and drill-seeded establishment were h2 = 0.50 and 0.26. Genetic correlations between seedling counts and heights under frost- and drill-seeded establishment were rA = 0.42 and 0.19 respectively. No significant genetic correlations between frost- and drill-seeded heights (rA = -0.09) or seedling counts (rA = 0.20) were detected. These results suggest that seedling performance in frost-seeded conditions is a distinct trait from seedling performance in standard drill-seeded conditions and that each needs a separate selection program.

Genetic parameters and gains for growth and wood properties in Florida source loblolly pine in the southeastern United States

2002 ◽  
Vol 32 (6) ◽  
pp. 1025-1038 ◽  
Author(s):  
Ryan A Atwood ◽  
Timothy L White ◽  
Dudley A Huber
Keyword(s):  
United States ◽  
Specific Gravity ◽  
Loblolly Pine ◽  
Growth Traits ◽  
Southeastern United States ◽  
Genetic Correlations ◽  
Wood Properties ◽  
Environment Interaction ◽  
Breeding Programs ◽  
Genotype Environment Interaction

One hundred and thirteen open-pollinated families from Florida source loblolly pine (Pinus taeda L.) were tested in four states in the southeastern United States. Heritabilities and genetic correlations were estimated for volume, specific gravity, and latewood percentage at three different growth stages: juvenile (ages 0–10 years), mature (11–17 years), and total (0–17 years). Heritabilities of growth traits (0.09–0.11) were consistently lower than for wood property traits (0.16–0.33). Growth traits for Florida loblolly exhibited high genotype × environment interaction (rB = 0.44), whereas wood properties did not (rB = 0.90). The higher heritabilities and genetic stability across environments make wood properties amenable to genetic manipulation through breeding programs. In contrast, the high genotype × environment interaction of growth traits for Florida loblolly pine requires more research to understand the possible implication of these effects on breeding programs. Trait–trait and age–age genetic correlations were determined for growth and wood properties. Strong positive age–age correlations were present for latewood percentage, volume, and specific gravity. Weak negative trait–trait genetic correlations existed between specific gravity and volume across ages (–0.13 to –0.43). No genetic correlation existed between latewood percentage and volume, while a moderate favorable genetic correlation existed between latewood percentage and specific gravity (0.47 to 0.59). Genetic gains in volume and specific gravity were compared for various types of selection. In one type, forward selection of the top 20 individuals (of 3484) based on 17-year volume, resulted in a 20.5% genetic gain in volume; however, a concomitant loss of –6.4% also occurred in specific gravity. If a selection index was used to hold specific gravity constant, a gain in total volume of 14% was obtained.

scholarly journals Diallel Crossing in Pinus cembra: V. Age Trends in Genetic Parameters and Genetic Gain for Height

2012 ◽  
Vol 61 (1-6) ◽  
pp. 66-79
Author(s):  
I. Blada ◽  
F. Popescu
Keyword(s):  
Genetic Gain ◽  
Growth Traits ◽  
Block Design ◽  
Genetic Correlations ◽  
Field Testing ◽  
Phenotypic Variance ◽  
Total Height ◽  
Testing Period ◽  
Randomized Block Design ◽  
Diallel Mating Design

AbstractA full diallel mating design (10 parents) was carried out in a Swiss stone pine panmictic population from the Carpathian Mountains. At age six, after nursery testing, the progenies were field planted to one site, using a completely randomized block design with 100 families, four replicates and a 15 tree row-plot per replication, spaced 2.5 × 2.5 m. Total and annual height of all individuals of this test was assessed at successive ages, between ages eight and 16. In addition, weight of 100 seeds and cotyledon number were considered in correlation analyses. Significant differences occurred in total height for general and specific combining ability effects. Variance components, heritabilities, genetic correlations and genetic gains on growth traits and survival at age 16 were estimated. Across the field testing period, GCA3)variance increased with time, accounting for 65% of plot mean phenotypic variance by age 16. In contrast, SCA variance declined as the progeny test aged accounting for only 9% by age 16. The time trend of the four heritability estimates for total height increased with age across the testing period reaching their highest level between age 14 and 16. Genetic correlations over time for total height rose from 0.85 at age two to 0.94 at age six and then leveled off across the field test indicating that if the goal is to improve 16-year height, early selection can be considered at age six. By selecting the best 10%, 15% and 20% of individuals within the best fullsib families, a genetic gain in total height of 12.4 %, 11.0% and 9.9% respectively, could be achieved at age 16. A higher gain can be obtained if the best general combiner parents are selected and intermated.

scholarly journals Genetic Parameter Estimates for Growth Traits from Diallel Tests of Loblolly Pine Throughout the Southeastern United States

2008 ◽  
Vol 57 (1-6) ◽  
pp. 101-110 ◽  
Author(s):  
S. E. Mckeand ◽  
B. Li ◽  
J. E. Grissom ◽  
F. Isik ◽  
K. J. S. Jayawickrama
Keyword(s):  
United States ◽  
Loblolly Pine ◽  
Growth Traits ◽  
Additive Genetic Variance ◽  
Southeastern United States ◽  
Genetic Correlations ◽  
Parameter Estimates ◽  
Narrow Sense ◽  
Improvement Program ◽  
Individual Tree

Abstract Variation in heritability and in genetic correlation estimates were evaluated for juvenile tree height and volume for six testing areas of loblolly pine (Pinus taeda L.) in the southeastern United States. Variance components and their functions (heritability and type B genetic correlations) were estimated from 265 six-parent disconnected diallel series, tested in almost 1000 trials (4 tests per diallel series). Original data were collected at age 6 years from about one million trees (265 diallel series x 30 crosses x 36 trees per cross/site x 4 sites) planted in field tests. Genetic tests were from the second cycle of breeding in the North Carolina State University - Industry Cooperative Tree Improvement Program. The overall unbiased individual-tree narrow-sense heritability for height was 0.19 and for volume was 0.16. The broad-sense heritabilities for height (0.24) and for volume (0.22) were higher than narrow-sense heritabilities due to the presence of non-additive genetic variance. There were moderate regional differences in these estimates, with tests in the Lower Gulf Coastal Plain tending to have the highest heritabilities for growth traits. There was very little association between site index and heritability, but heritabilities were higher on sites with the highest survival and highest test precision. Genotype x environment interactions were generally low both for half-sib and full-sib families, indicating that families can be operationally deployed to different sites with little concern about unpredictable performance.

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