An analysis of pre-weaning deaths in rabbits with special emphasis on enteritis and pneumonia. II. Genetic sources of variation

1967 ◽  
Vol 9 (1) ◽  
pp. 93-97 ◽  
Author(s):  
W. C. Rollins ◽  
R. B. Casady
Keyword(s):  
Genetic Correlation ◽  
Death Rate ◽  
Genetic Effects ◽  
Experiment Station ◽  
Sources Of Variation ◽  
Heritability Estimates ◽  
The Difference ◽  
Additive Genetic Effects ◽  
The U.S

Heritability estimates of death from enteritis or pneumonia, the two major causes of pre-weaning death at the U.S. Rabbit Experiment Station, Fontana, California, have been estimated. The data consisted of 15,329 observations made at the station from 1946 to 1961.From birth to 14 days of age the death rate over the years increased from 0·2 to 6·1% During the period from 15 days to 56 days of age (weaning) the enteritis death rate was quite constant over the years (7·5%) while that of enteritis or pneumonia increased from 8·3% to 13·2%.Heritability of death from enteritis or pneumonia for the period 15 to 56 days of age was estimated on the basis of paternal half sib analysis to be 0·12 ± 0·02. Based on an analysis of differences between dams within sires the corresponding estimate was 0·58 ± 0·05. The difference between the two estimates was attributed to maternal and non-additive genetic effects.The genetic correlation between the two diseases under discussion was estimated to be 0·66 and 0middot;57 on the basis of differences among sires and among dams within sires respectively.Breeding plans are suggested on the basis of the parameters estimated.

An analysis of pre-weaning deaths in rabbits with special emphasis on enteritis and pneumonia. I. Non-genetic sources of variation

1967 ◽  
Vol 9 (1) ◽  
pp. 87-92 ◽  
Author(s):  
W. C. Rollins ◽  
R. B. Casady
Keyword(s):  
Ambient Temperature ◽  
Litter Size ◽  
Death Rate ◽  
The Other ◽  
Experiment Station ◽  
Sources Of Variation ◽  
The U.S

Non-genetic sources of variation in pre-weaning death losses due to enteritis or pneumonia have been investigated using records of 15,329 rabbits born during the years 1946–61 in the random bred colony at the U.S. Rabbit Experiment Station at Fontana, California. Under consideration were periods of years, season within years, litter size, parity of doe, and fostering.For enteritis there was a statistically significant effect of season due to a negative regression of death rate on ambient temperature. For pneumonia, periods of years were statistically significant due to an increase in later years in deaths during the first 14 days of life. The other sources of variation studied were of negligible importance.

Estimates of genetic parameters for growth and skeletal measurements in Thai swamp buffalo

2000 ◽  
Vol 70 (3) ◽  
pp. 399-406
Author(s):  
K. Meyer ◽  
H. -U. Graser ◽  
A. Na-Chiangmai
Keyword(s):  
Total Variation ◽  
Genetic Association ◽  
Maternal Effects ◽  
Genetic Parameters ◽  
Genetic Effects ◽  
Environmental Correlations ◽  
Length Measurements ◽  
Swamp Buffalo ◽  
Heritability Estimates ◽  
Additive Genetic Effects

AbstractEstimates of genetic parameters were obtained for weight, hip height, heart girth and shoulder to pin length measurements on Thai swamp buffalo, recorded at birth and weaning. Direct heritability estimates were 0·26 for weights at both ages and were low for skeletal measurements, ranging from 0·11 to 0·19. Low values could, in part at least, be caused by inaccuracies in recording. All traits were subject to maternal effects, permanent environmental maternal effects on traits recorded at weaning explaining proportionately up to 0·14 of the total variation. Estimates of genetic (direct and maternal) and permanent environmental correlations between traits recorded at the same time were high throughout, ranging from 0·83 to 0·97 for additive genetic effects and being close to unity otherwise. Except for heart girth measured at weaning, there appeared to be comparatively little genetic association between traits recorded at different times, direct additive correlation estimates ranging from 0·18 to 0·55 in contrast to estimates of 0·38 to 0·65 for correlations with heart girth at weaning.

Inheritance of aluminium tolerance in Phalaris aquatica L

1986 ◽  
Vol 37 (4) ◽  
pp. 397 ◽  
Author(s):  
RA Culvenor ◽  
RN Oram ◽  
JT Wood
Keyword(s):  
Genetic Correlation ◽  
Breeding Population ◽  
Solution Culture ◽  
Aluminium Tolerance ◽  
Staining Procedure ◽  
Highly Sensitive ◽  
Sib Families ◽  
Heritability Estimates ◽  
The Difference ◽  
Further Development

The inheritance of aluminium tolerance in P. aquatica was investigated in solution culture, and correlations with other screening systems were determined. In the Israeli cultivar, Noy, the difference between the highly sensitive and moderately tolerant classes, which had been resolved in earlier experiments, can be largely explained by a two-gene hypothesis in which tolerance requires at least one dominant allele at each locus. Modifiers of these genes may also be involved. Assuming that the extensive continuous variation within the moderately tolerant class is polygenic, a quantitative inheritance study was conducted in a population of half-sib families in a diverse breeding population, the sensitive class being eliminated on performance in solution. Heritability estimates for relative root extension in solution ranged from 0.48 to 0.75, and estimated response to selection was high. However, heritability estimates for shoot growth of the same plants on a field site high in aluminium were low and non-significant (0.07-0.26). The highest estimate of genetic correlation between solution and field was not significant at 0.56. Variability in soil aluminium concentrations appeared to be a major cause of these low values. Prior screening of the population using a haematoxylin root-staining procedure gave a significant genetic correlation with solution responses (0.48). However, the technique requires further development for screening phalaris. In breeding for improved tolerance, the highly sensitive class could be eliminated by test crossing potential parents with homozygous sensitive plants. Several generations of selection could then be imposed, which, on the basis of genetic parameters estimated from solution screening, should yield a population appreciably more aluminium-tolerant than existing cultivars.

scholarly journals Genetic and environmental effects on sexual precocity traits in Nellore cattle

2009 ◽  
Vol 38 (8) ◽  
pp. 1488-1493 ◽  
Author(s):  
Sarah Laguna Meirelles ◽  
Ana Carolina Espasandin ◽  
Maira Mattar ◽  
Sandra Aidar de Queiroz
Keyword(s):  
Genetic Correlation ◽  
Threshold Model ◽  
Genetic Effects ◽  
Residual Effects ◽  
Sexual Precocity ◽  
Contemporary Group ◽  
Scrotal Circumference ◽  
Nellore Cattle ◽  
Genetic Evaluations ◽  
Additive Genetic Effects

The objective of this study was to estimate the heritability of probability of early pregnancy (PEP) and scrotal circumference (SC) and the genetic correlation between these traits in Nellore cattle. PEP records from 11,696 Nellore females born between 1983 and 2001 were analyzed. PEP was assumed to be one for females that effectively bred in the herd (19.84%) and zero for those discarded before first calving (80.16%). The model used to study PEP included the effects of contemporary group, age of dam at calving and heifer weaning age, direct additive genetic effects, and residual effects. For SC, 9335 records were analyzed considering the effect of contemporary group, direct additive genetic effects and residual effects. Covariance components were estimated by Gibbs sampling applied to a two-trait sire model, using a threshold model for PEP and a linear model for SC. Estimated mean heritability was 0.47 ± 0.05 for PEP and 0.27 ± 0.03 for SC, and the genetic correlation between traits was 0.12 ± 0.20. These results indicated the existence of additive genetic variation for PEP and this trait should therefore respond to selection. The estimated genetic correlation between PEP and SC indicated a low, but favorable, association. Thus, SC might be used together with PEP in genetic evaluations of sexual precocity. This procedure would increase the accuracy of predicting expected progeny differences for PEP.

scholarly journals Combining ability and heritability estimates of main agronomic characters in rapeseed breeding lines using line × tester analysis

2012 ◽  
Vol 57 (3) ◽  
pp. 111-120 ◽  
Author(s):  
Valiollah Rameeh
Keyword(s):  
Seed Yield ◽  
Combining Ability ◽  
Yield Components ◽  
Seed Weight ◽  
Oil Content ◽  
Genetic Effects ◽  
Narrow Sense Heritability ◽  
Breeding Lines ◽  
Heritability Estimates ◽  
Additive Genetic Effects

To estimate the general and specific combining ability (GCA and SCA) effects of plant height, yield components, seed yield and oil content, three testers and six lines of spring type of rapeseed varieties were crossed using line ? tester fashion. Significant mean squares of parents and crosses for all the traits indicated significant genetic variation among the parents and their F1 crosses. Significant mean squares of parents vs crosses revealed significant average heterosis for all the traits except seeds per pod, 1000-seed weight and oil content. High narrow-sense heritability estimates for all the traits except seeds per pod, indicating the importance of additive genetic effects for these traits. Due to more importance of additive genetic effects for most of the traits, only a few of the crosses exhibited significant SCA effects. A significant positive correlation between seed yield and some of yield components including pods on main axis, pods per plant and 1000-seed weight indicates that these traits can be used as suitable selection criteria for improving of seed yield. The crosses including Opt ? R01, RG06 ? R01, RG06 ? R08 and RGS3 ? R08 with 3241.91, 3213.68, 3334.28 and 3237.45 kg ha-1 of seed yield detected as prior combinations for improving of this trait and all of these combinations had also positive SCA effect for this trait.

Relative Importance of Additive Genetic and Maternal Sources of Variation in Early Survival of Young Splake Hybrids (Salvelinus fontinalis × S. namaycush)

1974 ◽  
Vol 31 (9) ◽  
pp. 1499-1502 ◽  
Author(s):  
G. Burton Ayles
Keyword(s):  
Maternal Effects ◽  
Salvelinus Fontinalis ◽  
Genetic Effect ◽  
Genetic Effects ◽  
Additive Genetic Effect ◽  
Relative Importance ◽  
Egg Survival ◽  
Brood Stock ◽  
Sources Of Variation ◽  
Additive Genetic Effects

Additive genetic and maternal effects of survival of uneyed eggs, eyed eggs, and alevins were determined from five series of matings within a splake brood stock. Average values for family h2 (heritability) and family m (maternal variance/total variance) were estimated. There were additive genetic effects in alevin survival (h2 =.41 ±.18) but not in uneyed or eyed egg survival. Maternal effects were greatest within the uneyed stage (m =.78 ±.22), decreased during the eyed egg stage (m =.68 ±.24), and were least within the alevin stage (.40 ±.19). The additive genetic effect on alevin survival was attributable to genetic differences in the resistance of young splake to blue sac disease (h2 =.76 ±.28).

scholarly journals The Impact of Non-additive Effects on the Genetic Correlation Between Populations

2019 ◽  
Vol 10 (2) ◽  
pp. 783-795 ◽  
Author(s):  
Pascal Duenk ◽  
Piter Bijma ◽  
Mario P. L. Calus ◽  
Yvonne C. J. Wientjes ◽  
Julius H. J. van der Werf
Keyword(s):  
Genetic Correlation ◽  
Complex Traits ◽  
Genetic Model ◽  
Allele Frequencies ◽  
Additive Effects ◽  
Simulated Genotype ◽  
The Difference ◽  
Allelic Interaction ◽  
Additive Genetic Effects ◽  
The Impact

Average effects of alleles can show considerable differences between populations. The magnitude of these differences can be measured by the additive genetic correlation between populations (rg). This rg can be lower than one due to the presence of non-additive genetic effects together with differences in allele frequencies between populations. However, the relationship between the nature of non-additive effects, differences in allele frequencies, and the value of rg remains unclear, and was therefore the focus of this study. We simulated genotype data of two populations that have diverged under drift only, or under drift and selection, and we simulated traits where the genetic model and magnitude of non-additive effects were varied. Results showed that larger differences in allele frequencies and larger non-additive effects resulted in lower values of rg. In addition, we found that with epistasis, rg decreases with an increase of the number of interactions per locus. For both dominance and epistasis, we found that, when non-additive effects became extremely large, rg had a lower bound that was determined by the type of inter-allelic interaction, and the difference in allele frequencies between populations. Given that dominance variance is usually small, our results show that it is unlikely that true rg values lower than 0.80 are due to dominance effects alone. With realistic levels of epistasis, rg dropped as low as 0.45. These results may contribute to the understanding of differences in genetic expression of complex traits between populations, and may help in explaining the inefficiency of genomic trait prediction across populations.

Genetic Variability and Heritability Estimates Based on the F2 Generation from Crosses of Large-Seeded Virginia-Type Peanuts with Lines Resistant to Cylindrocladium Black Rot1

1983 ◽  
Vol 10 (1) ◽  
pp. 47-51 ◽  
Author(s):  
C. C. Green ◽  
J. C. Wynne ◽  
M. K. Beute
Keyword(s):  
Genetic Effects ◽  
Fruit Traits ◽  
Resistant Lines ◽  
The Common ◽  
Low Levels ◽  
Selection For ◽  
Heritability Estimates ◽  
F2 Generation ◽  
Additive Genetic Effects ◽  
Selection Of

Abstract Selection of large-fruited, high-yielding Cylindrocladium black rot — (CBR) resistant lines from two sets of crosses, each set consisting of crosses in F2 generation between a virginia and two CBR-resistant lines, was evaluated to determine the potential for selecting cultivars with these traits. Heritabilities, phenotypic and genotypic correlations and estimates of additive and nonadditive genetic effects were determined for yield and fruit traits at two locations and CBR resistance at one location. Crosses with NC 2 as a parent had higher levels of CBR resistance than those with Florigiant as the common virginia-type parent. Heritability estimates for the necrosis index (CBR resistance) were high while estimates for yield and fruit traits were variable over crosses and locations. The necrosis index was significantly and negatively correlated with all fruit and yield traits for three of the four crosses indicating it should be possible to select high-yielding, largefruited lines with low levels of disease from three crosses. Only significant additive genetic effects were found for CBR resistance. Significant additive and nonadditive genetic effects were found for the yield and fruit traits. Estimates of additive and non-additive genetic effects indicate that early generation selection for CBR resistance should be effective, whereas selection for yield and fruit traits would be more effective in later generations.

scholarly journals Genetic parameters for calving ease, gestation length and stillbirth in three endangered Austrian blond cattle breeds

2009 ◽  
Vol 52 (6) ◽  
pp. 553-560
Author(s):  
S. Manatrinon ◽  
B. Fürst-Waltl ◽  
R. Baumung
Keyword(s):  
Animal Model ◽  
Genetic Correlation ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Genetic Effects ◽  
Gestation Length ◽  
Calving Ease ◽  
Cattle Breeds ◽  
Heritability Estimates

Abstract. Genetic parameters were estimated for stillbirth, calving ease and gestation length in three endangered Austrian blond cattle breeds, Carinthian Blond, Murboden and Waldviertel Blond. REML analysis based on an animal model including direct and maternal genetic effects was applied. Direct heritability estimates for calving ease, stillbirth and gestation length varied from 0.003 to 0.111, 0.006 to 0.044 and 0.235 to 0.512, respectively, while maternal heritabilities ranged from 0.001 to 0.007 for calving ease, 0.005 to 0.014 for stillbirth, and 0.002 to 0.063 for gestation length. All pairwise genetic correlations for direct traits were generally moderate to high except for stillbirth-calving ease (−0.077, Carinthian Blond). The genetic correlations of all pairs of the 3 direct traits were positive for Murboden (0.520 to 0.700) and Waldviertel Blond (0.253 to 0.707) while negative genetic correlations were detected for Carinthian Blond (−0.077 to −0.943). Close positive genetic correlations were found between direct stillbirth and calving ease of Murboden (0.700) and between direct calving ease and gestation length of Waldviertel Blond (0.707), while a close negative genetic correlation was found between direct calving ease and gestation length of Carinthian Blond (−0.943).

Combining Ability of Plant Height and Yield components in Indian Mustard (Brassica junceaL.Czern & Coss.) under Salt affected Soil using Line×Tester Analysis

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
SHAILESH CHAND GAUTAM ◽  
MP Chauhan
Keyword(s):  
Plant Height ◽  
Seed Yield ◽  
Combining Ability ◽  
Yield Components ◽  
Indian Mustard ◽  
Heritability Estimate ◽  
Genetic Effects ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Additive Genetic Effects

Line × tester analysis of twenty lines and three testers of Indian mustard (Brassica juncea L. Czern & Coss.) cultivars were used to estimate general combining ability (GCA), specific combining ability (SCA) effects, high parent heterosis and narrow-sense heritability estimate for plant height, yield components and seed yield. Significant variance of line x tester for the traits like pods per plant and seed yield indicating non additive genetic effects have important role for controlling these traits. Significant mean squares of parents v/s crosses which are indicating significant average heterosis were also significant for all the traits except seeds per pod. High narrow-sense heritability estimates for all the traits except seeds per pod exhibited the prime importance of additive genetic effects for these traits except seeds per pod. Most of the crosses with negative SCA effect for plant height had at least one parent with significant negative or negative GCA effect for this trait. For most of the traits except pods per plant, the efficiency of high parent heterosis effect was more than SCA effect for determining superior cross combinations.

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