INHERITANCE OF CYCLIC HYDROXAMATES IN Zea mays L.

1981 ◽  
Vol 61 (3) ◽  
pp. 583-593 ◽  
Author(s):  
G. M. DUNN ◽  
B. J. LONG ◽  
D. G. ROUTLEY
Keyword(s):  
Zea Mays ◽  
Genetic Variance ◽  
Zea Mays L ◽  
Additive Genetic Variance ◽  
Hydroxamic Acids ◽  
Phenotypic Variance ◽  
High Concentration ◽  
Components Of Variance ◽  
Rapid Procedure ◽  
Colorimetric Reaction

Hydroxamic acids have been implicated in the resistance of corn (Zea mays L.) to both fungi and insects. In this study, five selected crosses were used among the four inbreds BxBx, bxbx, B49 and B37 to study inheritance of hydroxamates. Hydroxamate concentration in the parental, F1, F2 and backcross generations for each cross was estimated by a rapid procedure based upon the colorimetric reaction of hydroxamates with FeCl3. Components of variance and estimates of heritability were obtained by the procedures of Warner (1952). F2 and backcross data indicated that concentration of hydroxamates is controlled monogenically in the cross bxbx × BxBx and polygenically in the crosses bxbx × B49 and bxbx × B37. Estimates of gene number using the Castle-Wright formula indicated that hydroxamate concentration is conditioned in B49 and B37 by five and two loci, respectively. The addition of BxBx to either B49 or B37 increased the frequency of genotypes in F2 with a high concentration of hydroxamates. Additive genetic variance was the most important component of the phenotypic variance and resulted in estimates of heritability from 0.64 to 0.79. However, the dominance component of variance was considerably higher for crosses involving BxBx than for the crosses bxbx × B49 and bxbx × B37.

The Changes in Genetic and Environmental Variance With Inbreeding in Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 152 (1) ◽  
pp. 345-353 ◽  
Author(s):  
Michael C Whitlock ◽  
Kevin Fowler
Keyword(s):  
Drosophila Melanogaster ◽  
Large Scale ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Inbred Lines ◽  
Residual Variance ◽  
Phenotypic Variance ◽  
Population Bottlenecks ◽  
Environmental Variance ◽  
Components Of Variance

Abstract We performed a large-scale experiment on the effects of inbreeding and population bottlenecks on the additive genetic and environmental variance for morphological traits in Drosophila melanogaster. Fifty-two inbred lines were created from the progeny of single pairs, and 90 parent-offspring families on average were measured in each of these lines for six wing size and shape traits, as well as 1945 families from the outbred population from which the lines were derived. The amount of additive genetic variance has been observed to increase after such population bottlenecks in other studies; in contrast here the mean change in additive genetic variance was in very good agreement with classical additive theory, decreasing proportionally to the inbreeding coefficient of the lines. The residual, probably environmental, variance increased on average after inbreeding. Both components of variance were highly variable among inbred lines, with increases and decreases recorded for both. The variance among lines in the residual variance provides some evidence for a genetic basis of developmental stability. Changes in the phenotypic variance of these traits are largely due to changes in the genetic variance.

scholarly journals Parameters in the estimation of the most suitable F2 population size in conventional maize (Zea mays L.) breeding programs

Genetika ◽  
2010 ◽  
Vol 42 (3) ◽  
pp. 455-464
Author(s):  
Nenad Delic ◽  
Jovan Pavlov ◽  
Vojka Babic ◽  
Gordana Surlan-Momirovic ◽  
Tomislav Zivanovic
Keyword(s):  
Zea Mays ◽  
Genetic Variance ◽  
Zea Mays L ◽  
Phenotypic Variance ◽  
Broad Sense Heritability ◽  
Breeding Programs ◽  
F2 Population ◽  
Population Sizes ◽  
Coefficients Of Variations ◽  
Broadsense Heritability

The objective of the present study was to observe differences among four sizes of the F2 populations (100, 200, 300 and 500 plants) on the basis of test-crosses for grain yield according to the average values of the populations, genetic and phenotypic variances, genotypic and phenotypic coefficients of variations and broad-sense heritability. The values of genetic variance did not significantly differ over population sizes according to all possible comparisons, including the comparison of values obtained for the phenotypic variance. Furthermore, the values of broadsense heritability (67.8%-69%) did not significantly vary over different F2 population sizes. Genetic variability of the observed progenies, as a principal prerequisite of successful selection, was at the satisfactory level in all population sizes.

scholarly journals Efectos genéticos en híbridos de maíz tropical (Zea mays L.) III. Acame, mala cobertura y pudrición de mazorca.

2016 ◽  
Vol 7 (1) ◽  
pp. 47
Author(s):  
Gaspar Martínez ◽  
Humberto De León-Castillo
Keyword(s):  
Zea Mays ◽  
Genetic Variance ◽  
Zea Mays L ◽  
Additive Genetic Variance ◽  
Ear Rot ◽  
Humid Tropic ◽  
Single Cross ◽  
Main Effects ◽  
Single Cross Hybrids ◽  
Interaction Variance

This study report genetic effects for lodging, uncovered ears and ear rot, of 42 single cross hybrids made with seven lines developed in the humid tropic of México, and six lines developed in the dry tropic, using a North Caroline II mating design. Hybrid variation was mainly due to GCA variance, and scanty to SCA variance for all the three attributes, although for ear rot, SCA variance had a considerable role, too. Partitioning GCA variance, revealed humid tropic lines had highest contribution to lodging and ear covering variance, and dry tropic lines the highest contribution to ear rot variance. In addition, humid tropic lines had higher GCAxEnvironment interaction variance than dry tropic lines. In conclusion, GCA effects, which reveal additive genetic variance, were the main effects for all the three attributes, and that GCA effects were higher in humid tropic lines than those of the dry tropic, maybe due to their mobilization in a more ample and diverse region.

Genetic Variance and Selective Value of Ear Number in Corn ( Zea mays L.) 1

Crop Science ◽  
1968 ◽  
Vol 8 (5) ◽  
pp. 540-543 ◽  
Author(s):  
Charles A. Laible ◽  
V. A. Dirks
Keyword(s):  
Zea Mays ◽  
Genetic Variance ◽  
Zea Mays L ◽  
Ear Number

scholarly journals Effects on phenotypic variability of directional selection arising through genetic differences in residual variability

2004 ◽  
Vol 83 (2) ◽  
pp. 121-132 ◽  
Author(s):  
WILLIAM G. HILL ◽  
XU-SHENG ZHANG
Keyword(s):  
Genetic Variance ◽  
Environmental Variability ◽  
Phenotypic Variability ◽  
Additive Genetic Variance ◽  
Directional Selection ◽  
Frequency Change ◽  
Phenotypic Variance ◽  
Additive Effects ◽  
Genetic Covariance ◽  
Mean And Variance

In standard models of quantitative traits, genotypes are assumed to differ in mean but not variance of the trait. Here we consider directional selection for a quantitative trait for which genotypes also confer differences in variability, viewed either as differences in residual phenotypic variance when individual loci are concerned or as differences in environmental variability when the whole genome is considered. At an individual locus with additive effects, the selective value of the increasing allele is given by ia/σ+½ixb/σ2, where i is the selection intensity, x is the standardized truncation point, σ2 is the phenotypic variance, and a/σ and b/σ2 are the standardized differences in mean and variance respectively between genotypes at the locus. Assuming additive effects on mean and variance across loci, the response to selection on phenotype in mean is iσAm2/σ+½ixcovAmv/σ2 and in variance is icovAmv/σ+½ixσ2Av/σ2, where σAm2 is the (usual) additive genetic variance of effects of genes on the mean, σ2Av is the corresponding additive genetic variance of their effects on the variance, and covAmv is the additive genetic covariance of their effects. Changes in variance also have to be corrected for any changes due to gene frequency change and for the Bulmer effect, and relevant formulae are given. It is shown that effects on variance are likely to be greatest when selection is intense and when selection is on individual phenotype or within family deviation rather than on family mean performance. The evidence for and implications of such variability in variance are discussed.

scholarly journals ESTİMATİON OF GENETİC AND ENVİRONMENTAL PARAMETERS AFFECTİNG PRODUCTİVİTY İN MORKARAMAN SHEEP AND ECONOMİC EVALUATİON OF PARAMETERS

2021 ◽  
pp. 155-161
Author(s):  
Ufuk Karadavut ◽  
Burhan Bahadır ◽  
Volkan Karadavut ◽  
Galip Şimşek ◽  
Hakan İnci
Keyword(s):  
Genetic Parameters ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Environmental Parameters ◽  
Error Variance ◽  
Economic Importance ◽  
Phenotypic Variance ◽  
Economic Aspects ◽  
Evaluation Of Parameters ◽  
The Relationship

This study was carried out to protect the continuity of productivity in morkaraman sheep raised in Turkey and determine their economic importance. Morkaraman sheep are concentrated in the Eastern Regions of the country. The province of Bingöl, where the study was conducted, is located in this region and has an important morkaraman population. The study was carried out between 2008-2018. Sixty-eight morkaraman sheep were used during the study period out of 317 lambing lambs. In the study, the total number of lambs born per sheep (TNLBS), the number of weaned lambs (NWL), the weights of the lambs weaned per sheep (WLWS) and the total weight of the lambs weaned in the first period (TWLWFP) were determined. In addition, Additive genetic variance, Error variance, Phenotypic variance, Heritability and Ratio of error variation were determined for these variables. As a result, the correlation between the examined variables was significant and positive, except for the relationship between TNLBS and TWLWFP. The relationship between these two variables was significant but negative. Significant changes were also observed in terms of genetic parameters. It was concluded that the economic aspects of the examined variables should not be ignored in terms of sustainability. Keywords: Sheep, morkaraman, sustainability, genotypic and phenotypic variance.

scholarly journals Combining Ability for Quantitative Traits Under Normal And Heat Stress Conditions in Maize (Zea Mays L.)

2021 ◽  
Vol 50 (3) ◽  
pp. 659-669
Author(s):  
Neha Rani ◽  
Ram Balak Prasad Nirala ◽  
Awadhesh Kumar Pal ◽  
Tushar Ranjan
Keyword(s):  
Zea Mays ◽  
Heat Stress ◽  
Normal Condition ◽  
Combining Ability ◽  
Zea Mays L ◽  
Stress Conditions ◽  
High Yield ◽  
Components Of Variance ◽  
Reciprocal Crosses ◽  
Heat Stress Condition

Investigation was carried out to ascertain the genetic architecture for heat tolerance and yield components from diallel crosses in maize (Zea mays L.). The combining ability in both the normal and heat stress conditions revealed highly significant mean squares due to general combining ability (GCA) and specific combining ability (SCA) in both the direct and reciprocal crosses for all the characters except for anthesis-silking interval in normal condition of the reciprocal crosses. Estimate of components of variance for 13 characters revealed higher SCA variance than that of GCA and reciprocal crosses for all the characters. CML 411 was good general combiner for grain yield in both the conditions, whereas, CML 306 and CML 307 were good general combiners in heat stress condition, and CML 164, CML 304 and CML 305 were average general combiners in normal condition. On the basis of high yield, high SCA and at least high GCA of seed parent, the CML 411*CML 305 and CML 411*CML 307 were identified as promising hybrids for normal and heat stress conditions, respectively. Bangladesh J. Bot. 50(3): 659-669, 2021 (September)

scholarly journals A guide to using a multiple-matrix animal model to disentangle genetic and nongenetic causes of phenotypic variance

2018 ◽  
Author(s):  
Caroline E. Thomson ◽  
Isabel S. Winney ◽  
Oceane C. Salles ◽  
Benoit Pujol
Keyword(s):  
Animal Model ◽  
Genetic Variance ◽  
Genetic Relatedness ◽  
Additive Genetic Variance ◽  
Phenotypic Traits ◽  
Phenotypic Variance ◽  
Data Types ◽  
Evolutionary Potential ◽  
Recent Developments

AbstractNon-genetic influences on phenotypic traits can affect our interpretation of genetic variance and the evolutionary potential of populations to respond to selection, with consequences for our ability to predict the outcomes of selection. Long-term population surveys and experiments have shown that quantitative genetic estimates are influenced by nongenetic effects, including shared environmental effects, epigenetic effects, and social interactions. Recent developments to the “animal model” of quantitative genetics can now allow us to calculate precise individual-based measures of non-genetic phenotypic variance. These models can be applied to a much broader range of contexts and data types than used previously, with the potential to greatly expand our understanding of nongenetic effects on evolutionary potential. Here, we provide the first practical guide for researchers interested in distinguishing between genetic and nongenetic causes of phenotypic variation in the animal model. The methods use matrices describing individual similarity in nongenetic effects, analogous to the additive genetic relatedness matrix. In a simulation of various phenotypic traits, accounting for environmental, epigenetic, or cultural resemblance between individuals reduced estimates of additive genetic variance, changing the interpretation of evolutionary potential. These variances were estimable for both direct and parental nongenetic variances. Our tutorial outlines an easy way to account for these effects in both wild and experimental populations. These models have the potential to add to our understanding of the effects of genetic and nongenetic effects on evolutionary potential. This should be of interest both to those studying heritability, and those who wish to understand nongenetic variance.

Estimation of additive and dominance genetic variance components for female fertility traits in Iranian Holstein cows

2018 ◽  
Vol 156 (4) ◽  
pp. 565-569
Author(s):  
H. Ghiasi ◽  
R. Abdollahi-Arpanahi ◽  
M. Razmkabir ◽  
M. Khaldari ◽  
R. Taherkhani
Keyword(s):  
Dairy Cows ◽  
Variance Components ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Effects ◽  
Information Criteria ◽  
Phenotypic Variance ◽  
Dominance Variance ◽  
Dominance Genetic Variance ◽  
Estimated Heritability

AbstractThe aim of the current study was to estimate additive and dominance genetic variance components for days from calving to first service (DFS), a number of services to conception (NSC) and days open (DO). Data consisted of 25 518 fertility records from first parity dairy cows collected from 15 large Holstein herds of Iran. To estimate the variance components, two models, one including only additive genetic effects and another fitting both additive and dominance genetic effects together, were used. The additive and dominance relationship matrices were constructed using pedigree data. The estimated heritability for DFS, NSC and DO were 0.068, 0.035 and 0.067, respectively. The differences between estimated heritability using the additive genetic and additive-dominance genetic models were negligible regardless of the trait under study. The estimated dominance variance was larger than the estimated additive genetic variance. The ratio of dominance variance to phenotypic variance was 0.260, 0.231 and 0.196 for DFS, NSC and DO, respectively. Akaike's information criteria indicated that the model fitting both additive and dominance genetic effects is the best model for analysing DFS, NSC and DO. Spearman's rank correlations between the predicted breeding values (BV) from additive and additive-dominance models were high (0.99). Therefore, ranking of the animals based on predicted BVs was the same in both models. The results of the current study confirmed the importance of taking dominance variance into account in the genetic evaluation of dairy cows.

scholarly journals Combining ability study in waterlogged tolerant maize (Zea mays L.)

2014 ◽  
Vol 39 (2) ◽  
pp. 283-291 ◽  
Author(s):  
MN Amin ◽  
M Amiruzzaman ◽  
A Ahmed ◽  
MR Ali
Keyword(s):  
Combining Ability ◽  
Genetic Variance ◽  
Zea Mays L ◽  
Additive Genetic Variance ◽  
Diallel Cross ◽  
Kernel Weight ◽  
Hybrid Variety ◽  
Additive Gene ◽  
Ear Height ◽  
Kernel Yield

Combining ability was studied for kernel yield and yield components in a 8×8 diallel cross of waterlogged tolerant maize. Significant general and specific combining ability variances were observed for all the characters studied. Additive genetic variance was preponderant in plant height, ear height, ear length, ear diameter, and kernel weight and non-additive gene action was involved in days to silking, number of kernels per ear and kernel yield. The parental lines E-31 and E-79 were found to be the best general combiners for yield. The good combining parents for different traits could be used in hybridization to improve yield and other desirable traits as donor parents for the accumulation of favourable genes. The cross combinations, E 31× E 40, E 31× E 64, E 31× E 79, E 38× E 40, E 58× E 79, E 63× E 79, E 64 × E 79 showing significant and positive sca effects can be used for commercial hybrid variety development after verifying them at different locations. DOI: http://dx.doi.org/10.3329/bjar.v39i2.20430 Bangladesh J. Agril. Res. 39(2): 283-291, June 2014

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