scholarly journals Genetic parameters and efficiency of early selection for half rotation-aged growth and form traits in Pinus taeda in China

2013 ◽  
Vol 62 (1-6) ◽  
pp. 277-284 ◽  
Author(s):  
Huixiao Yang ◽  
Tianyi Liu ◽  
Chunxin Liu ◽  
Jinbang Wang ◽  
Kaer Chen ◽  
...  
Keyword(s):  
Pinus Taeda ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Early Selection ◽  
Direct Selection ◽  
Individual Tree ◽  
Stem Straightness ◽  
Selection For ◽  
Heritability Estimates

Abstract Genetic parameters for height (H), diameter at breast height (DBH), stem straightness (STR), and under crown clear bole height (CH) of loblolly pine (Pinus taeda L.) were estimated for 255 families (209 open pollinated (OP) and 46 controlled pollinated (CP) families) using a family model and an individual tree model at age 1, 2, 3, 5, 11, and 15 years. Heritability estimates for growth traits of individual trees at age 11 years were the highest (0.17-0.78), and those at age 15 years were the lowest (0.05-0.74). Heritability estimates for DBH, STR, and CH were lower than those for H. Genetic correlations between H and DBH were generally strongly positive, attained a maximum values at age 2 to 3, and declined slightly thereafter. The genetic correlations between CH at age 11 and both H and DBH at different ages were moderate. Age-age genetic correlations for growth traits were moderate to high (0.56-0.91) at age 5 for half-rotation age (15 years), indicating the opportunity exists for early selection. Indirect selection from the age 5 to 11 years for H and DBH could be expected to produce gains of over 50% and 35% respectively, for these two ages, relative to direct selection at age 15. Efficiencies of early selection for H and DBH indicated that growth at maturity could be improved by early selection.

scholarly journals Genetic Control of Growth Traits in Shortleaf Pine in Missouri

2005 ◽  
Vol 29 (4) ◽  
pp. 200-204 ◽  
Author(s):  
David P. Gwaze ◽  
Ross Melick ◽  
Charly Studyvin ◽  
Mark Coggeshall
Keyword(s):  
Growth Traits ◽  
Genetic Correlations ◽  
Selection Criterion ◽  
Seed Orchard ◽  
Direct Selection ◽  
Pinus Echinata ◽  
Shortleaf Pine ◽  
Individual Tree ◽  
High Heritability ◽  
Heritability Estimates

Abstract Genetic parameters for height (HT), diameter (diameter at breast height [dbh]), and volume for a shortleaf pine (Pinus echinata Mill.) population in Missouri were estimated from a single progeny test comprising 44 half-sibling families assessed at 3, 5, 7, 10, and 17 years. Individual tree heritability estimates for growth traits at age 10 years and younger were high (0.30–0.43), and those at age 17 years were low (0.11–0.24). Heritability estimates for dbh were lower than those for HT. Family mean heritability estimates were moderate to high (0.32–0.66). Genetic correlations were higher than their phenotypic counterparts for all growth traits. Age-age genetic correlations for growth traits were moderate to high (0.68–0.98), indicating opportunity for early selection. Genetic correlations between different growth traits were high (0.81–1.00). Indirect selection on age 5- or 7-year HTs may be expected to produce over 25% more volume at 17 years compared with direct selection for volume at age 17 years. Efficiencies of selection suggest that early HT is a better selection criterion for volume at older ages than dbh because of the high heritability at young ages and strong juvenile-mature genetic correlations. Genetic gain in an unrogued seed orchard was predicted to be 6.7 and 27.2% for 10- and 17-year volume, respectively. These results suggest that growth traits in shortleaf pine in Missouri have high genetic variation, and genetic improvement was effective. South. J. Appl. For. 29(4):200–204.

scholarly journals Genetic parameters by Bayesian inference for dual purpose Jaffarabadi buffaloes

2012 ◽  
Vol 55 (6) ◽  
pp. 567-576 ◽  
Author(s):  
C. H. Mendes Malhado ◽  
A. C. Mendes Malhado ◽  
A. Amorim Ramos ◽  
P. L. Souza Carneiro ◽  
F. Siewerdt ◽  
...  
Keyword(s):  
Bayesian Inference ◽  
Milk Yield ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Average Daily Gain ◽  
Genetic Correlations ◽  
Direct Selection ◽  
Dual Purpose ◽  
Lactation Length ◽  
Selection For

Abstract. Knowledge of genetic parameters is essential for improved reproductive management and increased yield. Quantitative analysis of genetic parameters is lacking for many breeds of buffaloes. This article provides the first estimate of genetic parameters for dual purpose (meat and milk) Brazilian Jaffarabadi buffaloes, using Bayesian inference. Data on milk yield (MY), lactation length (LL), weight at 205 days (W205) and 365 (W365) days of age, and average daily gain (ADG) from 205 to 365 days of age were collected in two herds. Bivariate analyses (using the program MTGSAM) were performed with the Gibbs sampler to obtain estimates of variance and covariance. Average lactation milk yield and lactation length were 1620.2±450.9 kg and 257.6±46.8 days, respectively, and the mean values for weight traits (kg) were 181.6±63.3 (W205), 298.04±116.1 (W365), and 0.73±0.35 (ADG). Heritability estimates (modes) were 0.16 for MY, 0.10 for LL, 0.43 for W205, 0.48 for W365 and 0.32 for ADG. There was a high genetic correlation (0.96) between milk yield and lactation length and very high genetic correlations (0.99) between the three growth traits. Our data suggest that both milk production and growth traits have clear potential for yield improvement through direct selection in this dual purpose breed. The selection for weight at an early age would be successful and selection for MY can be performed in the first lactation.

Phenotypic and genetic parameters for reproductive performance in a synthetic line of sheep

1981 ◽  
Vol 96 (1) ◽  
pp. 107-113 ◽  
Author(s):  
T. G. Martin ◽  
D. Nicholson ◽  
C. Smith ◽  
D. I. Sales
Keyword(s):  
Reproductive Performance ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Direct Selection ◽  
Sex Distribution ◽  
Regression Methods ◽  
Litter Weight ◽  
Heritability Estimates ◽  
Synthetic Line

SUMMARYData on 902 ewes (1755 records) bom over 7 years in the synthetic ABRO Dam Line were analysed by least squares. Reproductive traits of the ewe were not affected by whether she was a single or a twin or by the age of her dam. Ewe age had major effects on all reproductive traits. Litter weight traits were affected by the sex distribution and the age of the litter when weighed.Heritability estimates, both by half sib and regression methods, were low for litter size, low to moderate for litter weights, and higher for ewe and fleece weights. Genetic correlations among the litter-weight traits were high. Together with the heritability estimates, they indicated that selection on litter weight at birth (and perhaps other traits) might give a greater change in total litter weight at weaning, the main measure of ewe productivity and the objective in improvement, than would direct selection.

Estimates of genetic parameters for pre-weaning and post-weaning growth traits of Chios lambs

1980 ◽  
Vol 30 (2) ◽  
pp. 271-276 ◽  
Author(s):  
A. P. Mavrogenis ◽  
A. Louca ◽  
O. W. Robison
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Weaning Weight ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Daily Gain

ABSTRACTData on 792 Chios lambs born during the 1972/73 and 1973/74 lambing seasons were used to estimate genetic and phenotypic parameters for birth weight, weaning weight, age at weaning, pre-weaning daily gain, body weight at 5, 10, 15 and 20 weeks of age, and postweaning daily gain. Body weight at 15 weeks of age had the highest heritability estimate (0·73 ± 0·17) and that of post-weaning daily gain was also high (0·56 ± 0·15). Selection for either weight at 15 weeks or post-weaning daily gain would be expected to yield a greater response than selection for pre-weaning daily gain or weaning weight. Genetic correlations among weights and/or gains were positive (approximately 0·20). Phenotypic correlations among weights and gains were generally higher than genetic correlations. However, the correlation between pre— and post-weaning daily gain was small (0·08). Likewise, post-weaning daily gain had low correlations with all weights before 10 weeks. Age at weaning had moderate negative associations with all weights but a very low positive correlation with post-weaning daily gain.

Selection for cow lifetime pregnancy rate using bull and heifer growth and reproductive traits in composite cattle

2000 ◽  
Vol 80 (3) ◽  
pp. 507-510 ◽  
Author(s):  
P. B. Mwansa ◽  
R. A. Kemp ◽  
D. H. Crews Jr ◽  
J. P. Kastelic ◽  
D. R. C. Bailey ◽  
...  
Keyword(s):  
Birth Weight ◽  
Key Words ◽  
Pregnancy Rate ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Reproductive Traits ◽  
Genetic Change ◽  
Direct Selection ◽  
Scrotal Circumference ◽  
Selection For

Genetic correlations of lifetime pregnancy rate with bull and heifer growth and reproductive traits in a beef composite population were estimated. Yearling scrotal circumference had an unfavorable genetic correlation (rg = −0.25) while yearling tonometer score was favorably related (rg = 0.22) to lifetime pregnancy rate. Heifer pregnancy rate, birth weight, weaning weight, yearling weight and age at puberty in heifers had significant genetic correlations (rg = 0.97, 0.58, 0.57, 0.33 and −0.21, respectively) with lifetime pregnancy rate. Lifetime pregnancy rate may be successfully predicted by easy-to-measure heifer growth traits. Using indices including scrotal and heifer growth traits, annual genetic change in lifetime pregnancy rate may be increased 3.1 times compared with direct selection. Key words: Scrotal circumference, tonometer, pregnancy, reproduction, puberty

Genetic parameters of the duration of fertility in hens

1992 ◽  
Vol 72 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Catherine Beaumont
Keyword(s):  
Maximum Likelihood ◽  
Key Words ◽  
Genetic Parameters ◽  
Control Period ◽  
Genetic Correlations ◽  
The Other ◽  
Selection For ◽  
Heritability Estimates ◽  
Highly Correlated ◽  
Box Cox Transformation

After two successive artificial inseminations (AI) with 125 × 106 spermatozoa, various characteristics of the duration of fertility were observed in 2375 egg-type hens at 33 and 44 wk of age: number of fertile (F) or hatched (H) eggs during a 21-d control period after AI, early, medium or late embryonic mortalities occurring at the same time and efficient (De) and maximum (Dm) duration (i.e. time between AI and the first clear egg or the last fertile egg, respectively). Heritability estimates of F, H, De or Dm ranged from 0.08 to 0.31. All genetic correlations between these variables (measured at the same age) were high (0.45–0.99) as well as those between the same variable measured at different ages (0.30–0.97). Estimates of genetic parameters varied little when estimated by Henderson's method III or REML but with the second method only all estimates were within the parameter space. A Box-Cox transformation of data slightly modified heritability estimates and animal ranking after genetic evaluation. The best criterion of selection for duration of fertility seems to be H as it is economically important, well heritable and highly correlated with the other characteristics of duration of fertility. Key words: Genetic parameters, fertility, poultry, Restricted Maximum Likelihood

Estimation of Genetic Parameters and Selection Response for Reproductive and Growth Traits in Rideau-Arcott sheep

2020 ◽  
Author(s):  
Mohammed Naser Boareki ◽  
Luiz Brito ◽  
Angela Cánovas ◽  
V.R. Osborne ◽  
Flavio S Schenkel
Keyword(s):  
Litter Size ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Reproductive Traits ◽  
Selection Response ◽  
Direct Selection ◽  
Correlated Response ◽  
Response To Selection ◽  
Weaning Weight ◽  
Selection For

The goal of this study was to estimate genetic parameters and predict direct and correlated response to selection for lamb growth traits and ewe reproductive traits, based on single trait selection or combining multiple traits in an optimum index that targets total litter post-weaning weight in the first lambing as the main selection goal. Heritability estimates ranged from 0.04 to 0.19. Genetic correlations between growth and reproductive traits ranged from -0.24 to 0.15. The indirect response to selection for reproductive traits in later lambings, by selecting on first lambing performance, was 11 to 25% greater than direct selection. The response to indirect selection for composite reproductive traits, i.e. total weaning weight or total post-weaning weight, by selecting on individual lamb weaning weight or post-weaning weight was 1 to 69% greater than direct selection, but it was accompanied by a negative response on litter size. However, combining alternate growth and reproductive traits in optimum selection index resulted in correlated response of up to 96% greater than direct selection response for reproductive traits without a negative response on litter size. Therefore, multiple trait selection using an index of component traits was more effective than direct selection for a composite trait.

Efficiency of early selection for rotation-aged growth and wood density traits in Pinus radiata

2005 ◽  
Vol 35 (8) ◽  
pp. 2019-2029 ◽  
Author(s):  
Li Li ◽  
Harry X Wu
Keyword(s):  
Pinus Radiata ◽  
Growth Traits ◽  
Growth Ring ◽  
Genetic Correlations ◽  
Ring Width ◽  
Early Selection ◽  
Breast Height ◽  
Growth Ring Width ◽  
Cambial Age ◽  
Heritability Estimates

A total of 1097 cross-sectional wood disks from breast height were sampled from two rotation-aged (27 and 31 years from planting) genetic trials of radiata pine (Pinus radiata D. Don) in Australia to estimate the genetic correlation between early and rotation-aged growth and wood quality traits and the efficiency of early selection. Annual growth-ring width and density, diameter at breast height (DBH), and area-weighted density (AD) from 30 open-pollinated families were measured using X-ray densitometry. Genotype × site interactions were not significant for density and growth traits. Ring density increased steadily from the pith to cambial age 14, and then density had little change in the following years. For AD, the family and individual heritability estimates were about 0.60 and 0.30 after the first 2 years. For DBH, family and individual narrow-sense heritability estimates increased steadily after the first 4 years, and family heritability increased to 0.7 at a cambial age of 11 and had little change thereafter. Individual heritability estimate increased to 0.4 at cambial age 14 and was similar for the later ages. Beyond a cambial age of 5 years, there were strong negative genetic correlations of around –0.80 between AD and DBH. Age–age genetic correlations for AD were high and reached 0.80 and above after cambial age 3. Age–age genetic correlations for DBH were similar to AD, except the first two years. The most efficient early selection year was between ages 4 and 6 years after planting for AD, and between ages 8 and 11 years for DBH.

Environmental and genetic causes of variation in production traits of Damascus goats. 1. Pre-weaning and post-weaning growth

1984 ◽  
Vol 38 (1) ◽  
pp. 91-97 ◽  
Author(s):  
A. P. Mavrogenis ◽  
A. Constantinou ◽  
A. Louca
Keyword(s):  
Growth Rate ◽  
Genetic Parameters ◽  
Genetic Factors ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Production Traits ◽  
Factors Influencing ◽  
Sire Family ◽  
Selection For ◽  
Birth Type

ABSTRACTData on 1542 Damascus kids, collected from 1977 to 1981, were used to study environmental and genetic factors influencing pre-weaning and post-weaning growth traits of kids. Season of birth, type of birth, sex of kid and dam lactation number were the environmental factors investigated. Phenotypic and genetic parameters were estimated from paternal half-sib correlations. The average sire family size was 17·2 kids. Single kids were heavier at birth, at weaning and at 140 days of age than twins or other multiples (P < 0·01). Male kids were heavier (P < 0·01) and grew faster (P < 0·01) than female kids from birth to 140 days of age (4·7 and 4·2 at birth, and 29·2 and 24·6 kg at 140 days, respectively). Dam lactation number significantly affected pre-weaning growth, but had no effect on the post-weaning growth rate of kids.Heritabilities for birth, weaning and 140-day weights, and pre-weaning and post-weaning growth rate, were 0·31 (s.e. 0·08), 0·27 (s.e. 0·07), 0·21 (s.e. 0·07), 0·16 (s.e. 0·06) and 0·22 (s.e. 0·07), respectively. Genetic correlations were mostly high and all positive, especially between weaning weight and 140-day weight (0·82 (s.e. 0·08)), and pre-weaning growth rate and 140-day weight (0·80 (s.e. 0·10)). The corresponding phenotypic correlations were also high and positive (0·71 and 0·67, respectively). No genetic antagonisms were found among the characters studied. Response to selection for post-weaning growth should be effective.

scholarly journals Genetic Variation in an International Provenance-Progeny Test of Pinus caribaea Mor. var. bahamensis Bar. et Gol., in São Paulo, Brazil

2008 ◽  
Vol 57 (1-6) ◽  
pp. 181-187 ◽  
Author(s):  
A. M. Sebbenn ◽  
F. C. Arantes ◽  
O. V. Boas ◽  
M. L. M. Freitas
Keyword(s):  
Growth Traits ◽  
Genetic Correlations ◽  
Sao Paulo ◽  
Progeny Test ◽  
Direct Selection ◽  
São Paulo ◽  
Pinus Caribaea ◽  
Andros Island ◽  
Selection For ◽  
Analysis Of Variation

Abstract A combined provenance-progeny test of Pinus caribaea var. bahamensis was established in Paraguaçu Paulista Experimental Station, São Paulo State, Brazil, in a “compact family” blocks design with 14 provenances, 2 to 10 families per provenance, 5 individuals per subplot, and 7 replications. Variation among and within island, provenances and families and genetic parameters for d.b.h., height, and real volume were investigated, about 15 years after planting. Analysis of variation for all studied traits revealed significant differences among islands, provenances within island and families within islands, suggesting the possibility of increasing the timber yield through selection of the more productive provenances and families within the best island. Genetic correlations on growth traits were high and statistically significant, indicating that substantial gains could be made through indirect selection for one trait based on direct selection for another. Norman Castle provenance from Abaco Island performed best for d.b.h. height and volume, while San Andros and Little Harbour Cay, both from Andros Island performed worst for d.b.h. and height, respectively, and South Riding from Grand Bahamas Island performed worst for volume. The best provenance growth compared to that P. elliottii var. elliottii species at the same experimental site suggests that P. caribaea var. bahamensis has high silvicultural potential for the Paraguaçu Paulista region.

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