The effect of different levels of management on the assessment of differences within a variety of chicken

1967 ◽  
Vol 9 (1) ◽  
pp. 121-125 ◽  
Author(s):  
M. W. Oakes
Keyword(s):  
Egg Production ◽  
Genetic Correlations ◽  
Environment Interaction ◽  
Components Of Variance ◽  
Genotype Environment Interaction ◽  
Single Location ◽  
Body Weights ◽  
The Mean ◽  
Maximum Expression ◽  
Different Levels

The data relating to twenty single location trials, involving the progeny of seven sires from one variety mated with random females from another, have been analysed to obtain estimates of sire × location (genotype–environment) interaction for egg production, 23- and 64-week body weights and 32-and 45-week egg weights. In no case was a significant interaction found, indicating genetic correlations not significantly different from unity.The between- and within-sire components of variance have been calculated for each trait on each location separately. The regressions of these components on the mean levels at the locations have been obtained. Though low and non-significant, they tend to support the use of those locations giving maximum expression of a trait for comparisons involving that trait.

The effect of different levels of management on the assessment of differences between varieties of chickens. II. Egg production, mortality and egg weight

1964 ◽  
Vol 6 (2) ◽  
pp. 195-205 ◽  
Author(s):  
J. C. Bowman ◽  
J. C. Powell
Keyword(s):  
Egg Production ◽  
Genetic Correlations ◽  
Egg Laying ◽  
Components Of Variance ◽  
Egg Weight ◽  
The Mean ◽  
Intensive Investigation ◽  
Optimum Management ◽  
Maximum Expression ◽  
Different Levels

1. The data relating to 16 multi-location trials involving several varieties of egg-laying chickens per trial have been analysed to obtain estimates of variety × location (genotype-environment) interactions for rearing and laying mortality, hen-month and hen-housed egg production and 32-week egg weight. Significant interactions were found in about a third of the trials for all five traits though in only two cases did the interaction variance account for more than 20% of the total variance.2. Genetic correlations for varieties between locations have been calculated as 0·49 for rearing mortality, 0·50 for laying mortality, 0·72 for hen-month production, 0·76 for hen-housed production and 0·91 for egg weight. These are in close agreement with previous published estimates.3. The between-and within-variety components of variance have been calculated for each trait on each location separately. The regressions within trials and pooled values of the components on the mean level of all varieties on the location have been calculated. For hen-month production the pooled regres-son of the within-variety component on mean was negative, whilst for all other traits the pooled regressions were positive. The pooled regressions of the between-variety components on mean were all positive. It is suggested that this information indicates that comparison of varieties for single traits should be carried out on locations favourable for maximum expression of the trait. The difficulties which variety comparisons, for several traits having different optimum management regimes, would cause and the need for a more intensive investigation of the conditions conducive to genotype-environment interactions are stressed.

scholarly journals Genetic Variability of Fruit Set, Fruit Weight, and Yield in a Tomato Population Grown in Two High-temperature Environments

1992 ◽  
Vol 117 (5) ◽  
pp. 867-870 ◽  
Author(s):  
Linda Wessel-Beaver ◽  
J.W. Scott
Keyword(s):  
Puerto Rico ◽  
Genetic Variance ◽  
Fruit Set ◽  
Genetic Correlations ◽  
Fruit Weight ◽  
Environment Interaction ◽  
Significant Component ◽  
Genotype Environment Interaction ◽  
Single Location ◽  
Selection For

Heritabilities (h2) and genetic correlations between percent fruit set, yield, and fruit weight were estimated from one summer planting each in Florida and Puerto Rico of 100 S, tomato (Lycopersicon esculentum Mill.) families from a synthetic population. Single-location h2 was high for all traits. Across-locations h2 was low for yield, intermediate for fruit set, and high for fruit weight. Genotype × environment interaction (G × E) was 1) the only significant component of variance for yield, 2) somewhat important for fruit set, and 3) not an important variance component for fruit weight. The greater importance of genetic variance compared to G × E variance explains why across-location heritabilities for fruit weight and fruit set were high. Genetic correlations between fruit set and weight were strongly negative, while those between yield and set were large and positive. Yields under high temperatures may increase with selection for fruit set, but a reduction in fruit weight would be expected in this population and those with similar genetic correlations.

The effect of different levels of management on the assessment of differences between varieties of chickens. 1. Eight-week body weight

1962 ◽  
Vol 4 (3) ◽  
pp. 319-327 ◽  
Author(s):  
J. C. Bowman ◽  
J. C. Powell
Keyword(s):  
Body Weight ◽  
Broiler Chickens ◽  
Environment Interaction ◽  
Environmental Variance ◽  
Components Of Variance ◽  
Management Level ◽  
Genotype Environment Interaction ◽  
Predetermined Level ◽  
Mean Differences ◽  
Different Levels

1. Analyses of records of eight-week body weight in broiler chickens have been carried out to estimate the effect of management level (measured by mean body weight of all varieties on each farm) on the components of variance due to differences between and within varieties, and to find out if there is any evidence of genotype-environment interaction.2. It was found that as management improved, the between-variety genetic variance remained constant or possibly increased whilst the withinvariety (genetic and environmental) variance decreased markedly. The cause of these regressions is not known.3. In four cases out of six there were significant genotype-environment interactions. In two cases, the genetic correlation between the performance of varieties on different locations was significantly different from 1·0.4. It is suggested that on the basis of these findings it would be necessary to select between varieties on records taken from chickens maintained under conditions similar to those in which they will eventually be used. However, fewer chickens would be required to measure, with a predetermined level of accuracy, mean differences on well managed farms than on poorly managed ones.

Genetic parameters associated with characters effecting egg production in the domestic fowl. I. Heritability of total egg production during the pullet year

1956 ◽  
Vol 7 (6) ◽  
pp. 625 ◽  
Author(s):  
BL Sheldon
Keyword(s):  
Standard Error ◽  
Domestic Fowl ◽  
Egg Production ◽  
Genetic Parameters ◽  
Research Centre ◽  
Narrow Sense ◽  
White Leghorn ◽  
Components Of Variance ◽  
Production Index ◽  
The Mean

Egg production records of White Leghorn pullets hatched a t the Poultry Research Centre, Werribee, Vic., during 1947 to 1950 inclusive have been analysed both on a hen-housed (Production Index) and a survivor basis. Estimates of heritability were obtained by two methods: (1) by the analysis of components of variance between families of full sibs and half-sibs; (2) by estimating the intra-sire regression of the mean performance of offspring on dam's performance. Heritability, in the narrow sense, of Production Index during the pullet year is shown to be 23-30 per cent. with a reasonably low standard error, while heritability of survivors' production is slightly lower but not significantly so. Possible reasons are advanced for the low estimates of heritability of survivors' production.

Adaptation of field pea varieties to organic farming across different environments of Italy

2019 ◽  
Vol 70 (4) ◽  
pp. 327 ◽  
Author(s):  
Luciano Pecetti ◽  
Angelo R. Marcotrigiano ◽  
Luigi Russi ◽  
Massimo Romani ◽  
Paolo Annicchiarico
Keyword(s):  
Grain Yield ◽  
Southern Italy ◽  
Ascochyta Blight ◽  
Genetic Correlations ◽  
Field Pea ◽  
Environment Interaction ◽  
Adaptive Responses ◽  
Climatic Regions ◽  
Organic Systems ◽  
Genotype Environment Interaction

This study aimed to support field pea (Pisum sativum L.) breeding strategies for organic systems of southern European environments, by assessing the size of genotype × environment interaction (GEI) due to spatial and temporal factors across climatically contrasting regions and identifying plant characters associated with genotype adaptive responses. Twelve recent varieties were evaluated for grain yield and other traits in six organically managed environments (three sites × two cropping years) of northern, central and southern Italy. GEI for grain yield was large, with the variety × site × year interaction greatly exceeding the variety × site interaction. This finding, and the similar magnitude of the mean genetic correlations for variety yields across pairs of sites (rg = 0.56) and pairs of years (rg = 0.51), indicated the difficulty of exploiting variety × site interaction effects by breeding for specific climatic regions. Pattern analysis highlighted the large inconsistency across years for GEI pattern of the sites from central and southern Italy. GEI also complicated the targeting of varieties, owing to inconsistent top-performing material across years according to additive main effects and multiplicative interaction (AMMI)-modelled yields. Higher genotype mean yield was strictly associated (P < 0.01) with lower weed proportion (hence, greater competitiveness against weeds: r = –0.96), taller plants (r = 0.89) and larger seeds (r = 0.78), with looser associations with lower susceptibility to lodging and ascochyta blight. These traits, which also contributed to preferential adaptation to the moisture-favourable environments of northern Italy, could be selected in breeding widely adapted varieties.

scholarly journals Genetic variability for girth growth and rubber yield in Hevea brasiliensis

2006 ◽  
Vol 63 (3) ◽  
pp. 246-254 ◽  
Author(s):  
Paulo de Souza Gonçalves ◽  
Marcelo de Almeida Silva ◽  
Ligia Regina Lima Gouvêa ◽  
Erivaldo José Scaloppi Junior
Keyword(s):  
Hevea Brasiliensis ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Basic Knowledge ◽  
Environment Interaction ◽  
Genetic Characteristics ◽  
Genotype Environment Interaction ◽  
Genetic And Phenotypic Correlations ◽  
High Heritability ◽  
Selection Intensities

Basic knowledge of genetic characteristics of populations is necessary to conduct effective breeding and selection. The objective of this paper is describing the genetic variation of rubber yield and the correlation with other traits, and estimating the genetic parameters for girth growth and total number of latex vessels. Sixty seven clones of Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg. were tested at five sites during 10 years. Characters girth growth at panel opening and rubber yield, showed broad sense heritability on plot mean level, from 0.32 to 0.66 and 0.59 to 0.92, respectively. Predicted genetic gains equal to 0.73 cm and 0.79 g increase respectively on girth and yield in the opening panel and mature phases seems realistic, even with moderate selection intensities. Genetic correlations with rubber yield, bark thickness and total number of latex vessels were very large, and almost no genotype-environment interaction was present for girth growth. High genotype-environment interaction was present for rubber yield with genetic and phenotypic correlations across the sites, ranging from 0.64 to 0.92 (genetic) and 0.63 to 0.89 (phenotypic). Total number of latex vessels rings had a high heritability, ranging from 20.0% to 64.0% in the sites E and B, respectively.

scholarly journals The effect of raw soybeans in mixtures for laying hens on production performance and the relative weight of the pancreas

2014 ◽  
Vol 30 (1) ◽  
pp. 115-123
Author(s):  
V. Petricevic ◽  
M. Lukic ◽  
Z. Pavlovski ◽  
Z. Skrbic ◽  
Z. Jokic ◽  
...  
Keyword(s):  
Food Consumption ◽  
Egg Production ◽  
Laying Hens ◽  
Relative Weight ◽  
Production Performance ◽  
Heat Treated ◽  
Body Weights ◽  
Standard Level ◽  
Production Body ◽  
Different Levels

The study was conducted on Isa Brown hybrid hens at the age of 49-57 weeks. The effect of using different levels of share of raw soybean of two varieties in mixtures for feeding hens on egg production, body weight, food consumption, the occurrence of defective eggs, mortality and the relative weight of the pancreas was studied. The possibility of replacing the heat-treated soybean grains, varieties Lana, with reduced trypsin inhibitor (TI) and Lydia with a standard level of TI, with raw soybean grains was examined. The research was conducted on the principle of two factorial experiment 2 x 4 (2 varieties x 4 levels of share of raw grain in the mixture) with a total of 8 diet treatments and 4 replicates per each treatment. In the first 5 weeks of the study, the differences in the number of eggs produced under the influence of tested factors were not significant. Under the influence of soybean varieties, the level of share of raw soybean and interaction of the studied factors showed significant differences (p<0.01) after 53 week of age. The use of soy with lower TI in the diet for laying hens resulted in a significantly greater capacity compared to standard variety. The share of raw soybean grains of 8 % in the mixtures significantly reduced the number of eggs laid. The differences in body weights, food consumption, occurrence of defective eggs and the relative weight of the pancreas were not significantly influenced by the studied factors or by their interaction effect.

scholarly journals GENETIC AND PHENOTYPIC ASSOCIATIONS OF JUVENILE BODY WEIGHTS AND EGG PRODUCTION TRAITS IN TWO STRAINS OF RHODE ISLAND CHICKENS

2021 ◽  
Vol 18 ◽  
pp. 66-70
Author(s):  
O. O. ONI ◽  
B. Y. ABUBAKAR ◽  
S. O. OGUNDIPE
Keyword(s):  
Body Weight ◽  
Rhode Island ◽  
Sexual Maturity ◽  
Egg Production ◽  
Genetic Parameters ◽  
Laying Hens ◽  
Genetic Correlations ◽  
Selection Criterion ◽  
Production Traits ◽  
Body Weights

Data on body weight at 16 (WT16); 20 (WT20) weeks of age and at sexual maturity (WTSM) weight of first egg (WT1st), age at sexual maturity (ASM) and 120-d egg production (EN)  were used to estimate genetic parameters in 636 hens of two strains of Rhode Island chikens. There were significant (P.01) differences between  the two strains for all traits except for WTSM.The heritability estimates obtained ranged from 0.05 to 0.41 and 0.04 to 0.30 for strains 1 and 2 respectively. The genetic correlations obtained for the various traits were medium to high for the two strains. The phenotypic correlations were generally low but followed the same trend. The results indicate that selected stocks of the two strains would show improvements in egg production and age   at sexual maturity if juvenile body weight (WT20) is employed as a selection criterion at housing for laying hens.

scholarly journals Nest acceptance, clutch, and oviposition traits are promising selection criteria to improve egg production in cage-free system

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251037
Author(s):  
Lorry Becot ◽  
Nicolas Bedere ◽  
Thierry Burlot ◽  
Jenna Coton ◽  
Pascale Le Roy
Keyword(s):  
Rhode Island ◽  
Selection Criteria ◽  
Egg Production ◽  
Genetic Correlations ◽  
Breeding Systems ◽  
Likelihood Method ◽  
Free System ◽  
Genetic And Phenotypic Correlations ◽  
High Heritability ◽  
The Mean

In cage-free systems, laying hens must lay their eggs in the nests. Selecting layers based on nesting behavior would be a good strategy for improving egg production in these breeding systems. However, little is known about the genetic determinism of nest-related traits. Laying rate in the nests (LRN), clutch number (CN), oviposition traits (OT), and nest acceptance for laying (NAL) of 1,430 Rhode Island Red (RIR) hens and 1,008 White Leghorn (WL) hens were recorded in floor pens provided with individual electronic nests. Heritability and genetic and phenotypic correlations of all traits were estimated over two recording periods–the peak (24–43 weeks of age) and the middle (44–64 weeks of age) of production–by applying the restricted maximum likelihood method to an animal model. The mean oviposition time (MOT) ranged from 2 h 5 min to 3 h and from 3 h 35 min to 3 h 44 min after turning on the lights for RIR and WL hens, respectively. The mean oviposition interval ranged from 24 h 3 min to 24 h 16 min. All heritability and correlation estimates were similar for RIR and WL. Low to moderate heritability coefficients were estimated for LRN (0.04–0.25) and moderate to high heritability coefficients for CN and OT (0.27–0.68). CN and OT were negatively genetically correlated with LRN (-0.92 to -0.39) except during peak production for RIR (-0.30 to +0.43). NAL was weakly to moderately heritable (0.13–0.26). Genetic correlations between NAL and other traits were low to moderate (-0.41 to +0.44). In conclusion, CN and OT are promising selection criteria to improve egg production in cage-free systems. NAL can be also used to reduce the number of eggs laid off-nest in these breeding systems. However, variability in MOT must be maintained to limit competition for the nests.

scholarly journals AMMI and GGE Biplot Analysis for Stability of Yield in Mid-early Pigeonpea [Cajanus cajan (L.) Millspaugh] Genotypes

2022 ◽  
Author(s):  
P. Jagan Mohan Rao ◽  
N. Sandhyakishore ◽  
S. Sandeep ◽  
G. Neelima ◽  
A. Saritha ◽  
...  
Keyword(s):  
Block Design ◽  
High Yield ◽  
Environment Interaction ◽  
Gge Biplot ◽  
Genotype By Environment ◽  
Genotype Environment Interaction ◽  
Single Location ◽  
Randomized Complete Block Design ◽  
Advanced Stages ◽  
Superior Genotypes

Background: The genotype × environment interaction greatly influences the success of breeding and in multi-location trials complicates the identification of superior genotypes for a single location, due to magnitude of genotype by location interaction are often greater than genotype by year interaction. This necessitates genotype evaluation in multi environments trials in the advanced stages of selection. Methods: Nine elite pigeonpea genotypes of mid-early duration were evaluated in six diverse locations in randomized complete block design with three replications during kharif, 2019 to ascertain the stable genotypes, environments discrimination and genotype by environment crossovers using AMMI and GGE biplot stability models. Result: The results in the present investigation revealed that first two principal components explained 73.4% of variation interaction, while, 80.50% in GGE biplot. Both the models identified WRGE-126 (G6) as stable performer with high yield (1733 kg ha-1) and among the locations Tandur (E1) measured as the ideal environment. Whereas, the environments, Adilabad (E3) and Warangal (E4) were observed representative with better discriminating ability.

Sign in / Sign up

Export Citation Format

Share Document