A STUDY OF COMBINING ABILITY FOR SOME DEVELOPMENTAL TRAITS IN A DIALLEL SET OF CROSSES IN PEARL MILLET

1976 ◽  
Vol 18 (3) ◽  
pp. 429-435
Author(s):  
H. R. Chaudhary ◽  
S. Jana
Keyword(s):  
Pearl Millet ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Leaf Size ◽  
Diallel Cross ◽  
Pennisetum Typhoides ◽  
Genetic Variances ◽  
Considerable Impact ◽  
Nonallelic Interactions ◽  
Developmental Traits

A diallel cross involving ten selected inbred parents in pearl millet Pennisetum typhoides (Burm.) Staph and Hubb. was analyzed for the inheritance of number of functioning leaves and leaf size. The study revealed that both additive and dominance genetic variances were important for leaf size whereas additive genetic variance was of major importance for number of functioning leaves. However, nonallelic interactions evidently had considerable impact in the inheritance of both characters. Heritability for number of functioning leaves was higher than that for leaf size. Although specific and general combining abilities were significant for both characters, gca effect appeared to be more important than sca effect for both characters. It was proposed that a breeding procedure which could make an efficient use of both additive and nonadditive genetic variances would be appropriate for the improvement of pearl millet.

scholarly journals Variance component analysis for viability in an isolated population of Drosophila melanogaster

1983 ◽  
Vol 42 (2) ◽  
pp. 207-217 ◽  
Author(s):  
Hidenori Tachida ◽  
Muneo Matsuda ◽  
Shin-Ichi Kusakabe ◽  
Terumi Mukai
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variance ◽  
Balancing Selection ◽  
Additive Genetic Variance ◽  
Diallel Cross ◽  
Variance Component Analysis ◽  
Logarithmic Scale ◽  
Dominance Variance ◽  
Diversifying Selection ◽  
Partial Diallel

SUMMARYUsing the 602 second chromosome lines extracted from the Ishigakijima population of Drosophila melanogaster in Japan, partial diallel cross experiments (Design II of Comstock & Robinson, 1952) were carried out, and the additive genetic variance and the dominance variance of viability were estimated. The estimated value of the additive genetic variance is 0·01754±0·00608, and the dominance variance 0·00151±0·00114, using a logarithmic scale. Since the value of the additive genetic variance is much larger than expected under mutation–selection balance although the dominance variance is compatible with it, we speculate that in the Ishigakijima population some type of balancing selection must be operating to maintain the genetic variability with respect to viability at a minority of loci. As candidates for such selection, overdominance, frequency-dependent selection, and diversifying selection are considered, and it is suggested that diversifying selection is the most probable candidate for increasing the additive genetic variance.

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

scholarly journals Genetic Analysis of Yield Components in Cucumber at Low Plant Density

1997 ◽  
Vol 122 (4) ◽  
pp. 522-528 ◽  
Author(s):  
Felix C. Serquen ◽  
Jeff Bacher ◽  
Jack E. Staub
Keyword(s):  
Genetic Factors ◽  
Plant Density ◽  
Additive Genetic Variance ◽  
Leaf Size ◽  
Sex Expression ◽  
Genetic Variances ◽  
Lateral Branching ◽  
Minimum Number ◽  
Multiple Lateral Branching ◽  
Lateral Branches

Plant architecture can be manipulated in cucumber (Cucumis sativus L.) to provide an array of phenotypes. Determinate, multiple-lateral plants are unique because they afford an opportunity to increase fruit yield per plant. Estimates of genetic variances, numbers of genetic factors, and genotypic and phenotypic correlations between traits were made in a population, segregating for sex expression, leaf size, and plant habit at low plant density (≈19,000 plants/ha). Replicated evaluation of 100 F3 families derived from an initial mating between a gynoecious, determinate, moderately branched line (G421) and a monoecious, indeterminate, multiple lateral branching line (`H-19') indicated that mainstem length and multiple lateral branching exhibit mostly additive genetic variance. For sex expression, additive and dominant genetic variances were important. The minimum number of genetic factors controlling sex expression, number of lateral branches, and mainstem length were estimated at five, four, and eight, respectively. Phenotypic and genotypic correlations between traits indicated that relative leaf size may influence fruit mass while having only limited influence on the number of fruit produced per plant. The amount and type of genetic variation suggests that the development of an array of determinate, multiple-lateral branching plant types with varying sex expression and plant stature is possible.

scholarly journals GROWTH TRAIT'S AND YIELD EVAIUATION OF ITALIAN MAIZE INBRED LINES BY FULL DIALLEL CROSS

2017 ◽  
Vol 48 (3) ◽  
Author(s):  
Abed & et al.
Keyword(s):  
Reciprocal Cross ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Total Yield ◽  
Diallel Cross ◽  
Inbred Lines ◽  
Area Index ◽  
Positive Direction ◽  
Maize Inbred Lines ◽  
Degree Of Dominance

To evaluate five  maize inbred lines imported from Italy by  daillel and reciprocal crosses which predict from its, by estimate the heterosis ,general and specific combining ability effect(Gca,Sca,Rca), type of gene action and degree of dominance  for growth traits  and total yield. Field experiment was conducted during the two successive  seasons of 2013 , during spring  seasons full –diallel cross was carried out among inbred lines, In fall season a comparison experiment between the parents and the hybrids was carried by using randomized complete block design. The result show significant differences  for the  plant height (PH)(cm), ear height (EH)(cm) ,number of  leafs per plant(NLP) ,leaf area index(LA) ,the biomass(BI) and total yield per area(TY)(tan.h-1) which refer to high variation among the parents. The  inbred line Agostano  excel in TY (tan .h-1), NLP and  the BI, as such the DSP177  was excellence in ether traits  and the cross between  parents was deign high TY reach to 7.88 tan.h-1.The results of heterosis revealed the 20 cross in PH,15 cross in EH,14 cross in NLP and LAI, 17 cross in BI and 15 cross in TY  a positive direction desired for heterosis , best values for it  given from the  hybrid Hi39Antiguao x FLO1240 (128.9%) in TY . The genetic analyses emerged the greatest role of inheritable traits which to demonic effect and some for this inheritable to additive effect   where notes high significant for the GCA,SCA and RCA but the rate of the  Gca / Sca more loss  than one for all traits as well as the rate of Gca / Rca  except LAI in reciprocal cross which it more than one , as such the dominance genetic variance(δ2D)  which higher than the  additive genetic variance(δ2A), and high bored  sense heritability (h2bs%) ,and lower narrow  sense heritability (h2ns %)for the daillel cross all traits as well as the degree of dominance which more than one except the LA in reciprocal cross  , It can be conclude the possibility of benefit to breed the parents to produce diallel cross by  using the hybridization  method is the hybridization and  the  hybridization followed by selection to produce reciprocal cross  .

scholarly journals Animal models with group-specific additive genetic variances: extending genetic group models

2018 ◽  
Author(s):  
Stefanie Muff ◽  
Alina K. Niskanen ◽  
Dilan Saatoglu ◽  
Lukas F. Keller ◽  
Henrik Jensen
Keyword(s):  
Animal Model ◽  
Animal Models ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Group ◽  
Breeding Value ◽  
Sampling Variance ◽  
Implicit Assumption ◽  
Genetic Variances ◽  
Genetic Groups

Abstract1. The animal model is a key tool in quantitative genetics and has been used extensively to estimate fundamental parameters, such as additive genetic variance, heritability, or inbreeding effects. An implicit assumption of animal models is that all founder individuals derive from a single population. This assumption is commonly violated, for instance in cross-bred livestock breeds, when an observed population receive immigrants, or when a meta-population is split into genetically differentiated subpopulations. Ignoring genetic differences among different source populations of founders may lead to biased parameter estimates, in particular for the additive genetic variance.2. To avoid such biases, genetic group models, extensions to the animal model that account for the presence of more than one genetic group, have been proposed. As a key limitation, the method to date only allows that the breeding values differ in their means, but not in their variances among the groups. Methodology previously proposed to account for group-specific variances included terms for segregation variance, which rendered the models infeasibly complex for application to most real study systems.3. Here we explain why segregation variances are often negligible when analyzing the complex polygenic traits that are frequently the focus of evolutionary ecologists and animal breeders. Based on this we suggest an extension of the animal model that permits estimation of group-specific additive genetic variances. This is achieved by employing group-specific relatedness matrices for the breeding value components attributable to different genetic groups. We derive these matrices by decomposing the full relatedness matrix via the generalized Cholesky decomposition, and by scaling the respective matrix components for each group. To this end, we propose a computationally convenient approximation for the matrix component that encodes for the Mendelian sampling variance. Although convenient, this approximation is not critical.4. Simulations and an example from an insular meta-population of house sparrows in Norway with three genetic groups illustrate that the method is successful in estimating group-specific additive genetic variances and that segregation variances are indeed negligible in the empirical example.5. Quantifying differences in additive genetic variance within and among populations is of major biological interest in ecology, evolution, and animal and plant breeding. The proposed method allows to estimate such differences for subpopulations that form a connected meta-population, which may also be useful to study temporal or spatial variation of additive genetic variance.

ESTIMATION OF ADDITIVE AND NONADDITIVE GENETIC VARIANCES IN NONINBRED POPULATIONS UNDER SIRE OR FULLSIB MODEL

1989 ◽  
Vol 69 (1) ◽  
pp. 61-68
Author(s):  
C. Y. LIN ◽  
A. J. LEE
Keyword(s):  
Animal Model ◽  
Maximum Likelihood ◽  
Least Squares ◽  
Key Words ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Restricted Maximum Likelihood ◽  
Animal Breeding ◽  
Genetic Variances ◽  
Reml Estimation

The separation of additive and nonadditive genetic variances has been a problem for animal breeding researchers because conventional methods of statistical analyses (least squares or ANOVA type) were not able to accomplish this task. Henderson presented computing algorithms for restricted maximum likelihood (REML) estimation of additive and nonadditive genetic variances from an animal model for noninbred populations. Unfortunately, application of this algorithm in practice requires extensive computing. This study extends Henderson's methodology to estimate additive genetic variance independently of nonadditive genetic variances under halfsib (sire), fullsib nested and fullsib cross-classified models. A numerical example illustrates the REML estimation of additive [Formula: see text] and additive by additive [Formula: see text] genetic variances using a sire model. Key words: Genetic variance, additive, nonadditive, dairy

DOUBLED HAPLOIDS FOR ESTIMATING ADDITIVE EPISTATIC GENETIC VARIANCES IN SELF-POLLINATING CROPS

1980 ◽  
Vol 22 (1) ◽  
pp. 125-127 ◽  
Author(s):  
T. M. Choo
Keyword(s):  
Doubled Haploid ◽  
Genetic Variance ◽  
Doubled Haploids ◽  
Additive Genetic Variance ◽  
Genetic Variances ◽  
Doubled Haploid Lines

In this study it was shown that besides additive and additive × additive genetic variances, additive × additive × additive genetic variance can also be estimated from a diallel experiment in which each cross is represented by a number of doubled haploid lines.

THE GENETICS OF YIELD IN SPRING WHEAT (TRITICUM AESTIVUM L.)

1971 ◽  
Vol 13 (1) ◽  
pp. 110-114 ◽  
Author(s):  
P. D. Walton
Keyword(s):  
Triticum Aestivum ◽  
Spring Wheat ◽  
Genetic Variance ◽  
Developmental Stages ◽  
Flag Leaf ◽  
Additive Genetic Variance ◽  
Diallel Cross ◽  
Triticum Aestivum L ◽  
Morphological Characters ◽  
Wheat Cultivars

A diallel cross among eight spring wheat cultivars examined the inheritance of yield, its components, certain developmental stages and morphological characters above the flag leaf node. Additive genetic variance was important for all the characters studied. For yield, kernels per ear, ear volume and for the developmental stages considered dominance was also present. Results presented here agreed with the main conclusions drawn in four other diallels crosses which were reported previously.

scholarly journals Changes of genetic variances and heritability by effect of selection in a Mexican local variety of Squash

2020 ◽  
Vol 7 (5) ◽  
pp. 225-230
Author(s):  
Clemente Villanueva-Verduzco ◽  
José Antonio Ayala-Esteban ◽  
Evert Villanueva-Sanchez ◽  
Jaime Sahagen-Castellanos ◽  
Martha Blanca Guadalupe Irizar Garza
Keyword(s):  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Dry Weight ◽  
Fruit Weight ◽  
Local Variety ◽  
Genetic Variances ◽  
Dominance Genetic Variance ◽  
Sib Families ◽  
Combined Selection ◽  
Selection Of

A local variety of squash (Cucurbita pepo L.), ‘Round Zuchinni’ type from Los Reyes Acatlixhuayan State of México, México, was simultaneously evaluated and selected. The objective was to study effect of selection on genetic variance and heritability. Additive genetic variance decreased in seven of nine traits studied: fruit height (79.93 %); fruit weight (65.72 %); fruit width (60.91 %); flesh thickness (57.66 %); flesh color (43.70 %); dry weight of seed (39.54 %); flesh flavor (16.60 %); except in width and seed length traits where it increased 63.40 % and 0.81 %, respectively. Only weight of seed had dominance genetic variance. The coefficient of additive genetic variance (CVA) fluctuated from 9.4 to 61.7 % in the first cycle, and from 9.4 to 51.8 % in the second cycle of selection-evaluation among traits. Heritability diminished in seven from nine characters. In general, the estimated genetic variances (additive and dominance) and heritability decreased as a result of combined selection of falf sib families.

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