scholarly journals Genetic Analysis of Salinity Tolerance in Wheat (Triticum aestivum L.)

2021 ◽  
Author(s):  
Saeed Omrani ◽  
Ahmad Arzani ◽  
Mohsen Esmaeilzadeh Moghaddam ◽  
Mehrdad Mahlooji
Keyword(s):  
Salinity Tolerance ◽  
Genetic Basis ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Triticum Aestivum L ◽  
Total Chlorophyll ◽  
Dominance Model ◽  
Gene Effects ◽  
Quantitative Genetic ◽  
Seven Generations

Abstract Background: The understanding of the genetics of salt tolerance is of utmost need to combat the rising prevalence of soil salinity through employing tolerant cultivars. The current study was carried out to investigate the quantitative genetic basis of agronomical and physiological-related traits of salinity-stressed plants using the seven generations (parents, F1, F2, F3, and backcrosses) of wheat grown in the field under normal and saline conditions. Results: The combined analysis of variance showed highly significant effects of salinity and genotypes (generations) on all the traits. The scaling tests did not support the three-parameter model (additive-dominance model); hence, the six-parameter model was used to assess the genetic effects governing the traits in this study. The epistatic gene effects were crucial, as were additive and dominance gene effects for plant height, K/Na, and yield in salinity stress conditions. The highest heritability was observed for total chlorophyll, carotenoid, SPAD chlorophyll, and K/Na ratio in saline conditions. The additive genetic variance was more important than the dominance variance for grain weight, K, K/Na in salinity conditions. Conclusions: The findings of the current study may have important implications in the quantitative genetics of salinity tolerance and the development of cultivars tolerant to salinity in wheat.

scholarly journals Genetics of resistance to Fusarium stalk rot caused by Fusarium verticilloides in maize (Zea mays L.)

2020 ◽  
Vol 80 (04) ◽  
Author(s):  
B. M. Showkath Babu ◽  
H. C. Lohithaswa ◽  
A. Mohan Rao ◽  
N. Mallikarjuna
Keyword(s):  
Genetic Variance ◽  
Recurrent Selection ◽  
Additive Genetic Variance ◽  
Duplicate Gene ◽  
Genetic Effects ◽  
Reciprocal Recurrent Selection ◽  
Genetics Of Resistance ◽  
Dominance Model ◽  
Gene Effects ◽  
Stalk Rot

Fusarium stalk rot disease (FSR), incited by Fusarium verticilloides, is becoming an important biotic production constraint in many major maize growing areas causing substantial yield losses. The present investigation was conducted to understand the genetics of resistance to FSR through six generation means and variances, as a first step in addressing the problem. Five crosses were developed by crossing four FSR susceptible inbreds (VL1043, VL108867, VL121096 and VL1218) with two resistant inbreds (CM202 and CM212). Six generations of the five crosses (VL1043 × CM212, VL108867 × CM202, VL121096 × CM212, VL1218 × CM202 and VL1218 × CM212) were evaluated through artificial disease inoculation during post rainy season of 2018 and summer, 2019. The scaling tests and joint scaling tests indicated the inadequacy of additive-dominance model and showed the presence of epistatic gene effects in all the five crosses for FSR resistance. The study further revealed the importance of additive, dominance and additive × additive gene effects in the expression of FSR. The magnitude and direction of the additive genetic effects [a], dominance genetic effects [d], magnitudes of additive genetic variance (2A) and dominance genetic variance (2D) varied with the genetic background of the crosses over seasons. Duplicate gene interaction was evident in the inheritance of FSR resistance. Both, additive and non-additive components were found important thus reciprocal recurrent selection would be more effective in obtaining FSR resistant maize inbred lines.

scholarly journals Genetic constraints predict evolutionary divergence in Dalechampia blossoms

2014 ◽  
Vol 369 (1649) ◽  
pp. 20130255 ◽  
Author(s):  
Geir H. Bolstad ◽  
Thomas F. Hansen ◽  
Christophe Pélabon ◽  
Mohsen Falahati-Anbaran ◽  
Rocío Pérez-Barrales ◽  
...  
Keyword(s):  
Genetic Variance ◽  
Floral Morphology ◽  
Additive Genetic Variance ◽  
Genetic Data ◽  
Stabilizing Selection ◽  
Evolutionary Divergence ◽  
Genetic Constraints ◽  
Quantitative Genetic ◽  
Rates Of Evolution ◽  
Genetic Constraint

If genetic constraints are important, then rates and direction of evolution should be related to trait evolvability. Here we use recently developed measures of evolvability to test the genetic constraint hypothesis with quantitative genetic data on floral morphology from the Neotropical vine Dalechampia scandens (Euphorbiaceae). These measures were compared against rates of evolution and patterns of divergence among 24 populations in two species in the D. scandens species complex. We found clear evidence for genetic constraints, particularly among traits that were tightly phenotypically integrated. This relationship between evolvability and evolutionary divergence is puzzling, because the estimated evolvabilities seem too large to constitute real constraints. We suggest that this paradox can be explained by a combination of weak stabilizing selection around moving adaptive optima and small realized evolvabilities relative to the observed additive genetic variance.

COMBINING ABILITY FOR YIELD OF SYNTHETIC HEXAPLOID WHEATS

1974 ◽  
Vol 54 (2) ◽  
pp. 235-239 ◽  
Author(s):  
R. J. BAKER ◽  
P. L. DYCK
Keyword(s):  
Triticum Aestivum ◽  
Seed Yield ◽  
Combining Ability ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Triticum Aestivum L ◽  
Kernel Weight ◽  
Specific Combining Ability ◽  
Synthetic Hexaploid Wheats ◽  
Synthetic Hexaploid

Four hexaploid spring wheats (Triticum aestivum L.), which differ only in their D genomes, were crossed in all combinations. Heterosis was expressed in F1 and F2 for number of spikes, kernel weight, and seed yield. Failure to detect significant specific combining ability among F1 progeny suggests that only additive genetic variance is involved in the inheritance of these traits. Competition between single-spaced plants was detected.

scholarly journals Development of a Five-Parameter Model to Facilitate the Estimation of Additive, Dominance, and Epistatic Effects with a Mediating Using Bootstrapping in Advanced Generations of Wheat (Triticum aestivum L.)

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1325
Author(s):  
Ahmed E. A. Khalaf ◽  
Mohamed A. M. Eid ◽  
Kamal H. Ghallab ◽  
Sherif R. M. El-Areed ◽  
Ahmed A. M. Yassein ◽  
...  
Keyword(s):  
Gene Action ◽  
Mathematical Proof ◽  
Triticum Aestivum L ◽  
Algebraic Solution ◽  
Analysis Method ◽  
Dominance Model ◽  
Gene Effects ◽  
Local Varieties ◽  
Variable Generation ◽  
1000 Grain Weight

As a result of two crosses among three local varieties of wheat, five populations (P1, P2, F5, F6 and F7) were used as parents and grown during two successive seasons; 2016/2017 and 2017/2018. To estimate five types of gene action (e.g., mean effects, additive, dominance, additive × additive, and dominance × dominance), five formulas were developed from with algebraic solution, algebraic proof, and mathematical proof. Besides, to test adequate of a simple additive-dominance model, three formulas A, B, and C scaling test were developed. The path analysis method by PROCESS Macro, AMOS, and Bootstrapping was employed to assess the relationships between grain yield/plant (GYP) as the dependent variable and each one of the number of spikes (NS) and 1000-grain weight (TW) as the independent variables. The results show that there are eight validated equations used to estimate the scaling test (A, B and C) and five types of gene effects (m, a, D, I and L), respectively. Confidence interval using Bootstrapping results indicate that TW was played as the partial mediator between NS as an exogenous variable and GYP as an endogenous variable. Generation means analysis is a relatively simple and statistically reliable tool suitable for the fundamental estimation of different genetic influences.

scholarly journals Quantitative genetics of postponed aging in Drosophila melanogaster. II. Analysis of selected lines.

Genetics ◽  
1991 ◽  
Vol 127 (4) ◽  
pp. 729-737
Author(s):  
E W Hutchinson ◽  
A J Shaw ◽  
M R Rose
Keyword(s):  
Drosophila Melanogaster ◽  
Maternal Effects ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Starvation Resistance ◽  
Selected Lines ◽  
Quantitative Genetic ◽  
Degree Of Differentiation ◽  
Postponed Aging ◽  
Allelic Differentiation

Abstract Quantitative genetic analyses of Drosophila melanogaster stocks with postponed aging have suffered from the problem of a lack of certainty concerning patterns of allelic differentiation. The present experiments were designed to alleviate this difficulty by selecting for enhanced levels of characters known to be related to postponed aging. Selection successfully increased the degree of differentiation of postponed aging stocks with respect to starvation resistance and fecundity, but persistent additive genetic variance suggested that selection did not result in fixation of alleles. The artificially selected stocks were subjected to crosses to test for patterns of dominance and maternal effects. There was little evidence for these effects in the inheritance of the characters underlying postponed aging, even with the increased differentiation of the selected stocks.

scholarly journals Neutral additive genetic variance in a metapopulation

1999 ◽  
Vol 74 (3) ◽  
pp. 215-221 ◽  
Author(s):  
MICHAEL C. WHITLOCK
Keyword(s):  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Additive Model ◽  
Divergent Evolution ◽  
Fixation Index ◽  
Effective Population ◽  
Quantitative Genetic ◽  
Population Structures ◽  
Diploid Individual ◽  
Mutational Variance

For neutral, additive quantitative characters, the amount of additive genetic variance within and among populations is predictable from Wright's FST, the effective population size and the mutational variance. The structure of quantitative genetic variance in a subdivided metapopulation can be predicted from results from coalescent theory, thereby allowing single-locus results to predict quantitative genetic processes. The expected total amount of additive genetic variance in a metapopulation of diploid individual is given by 2Neσ2m (1 + FST), where FST is Wright's among-population fixation index, Ne is the eigenvalue effective size of the metapopulation, and σ2m is the mutational variance. The expected additive genetic variance within populations is given by 2Neσ2e(1 − FST), and the variance among demes is given by 4FSTNeσ2m. These results are general with respect to the types of population structure involved. Furthermore, the dimensionless measure of the quantitative genetic variance among populations, QST, is shown to be generally equal to FST for the neutral additive model. Thus, for all population structures, a value of QST greater than FST for neutral loci is evidence for spatially divergent evolution by natural selection.

scholarly journals ESTIMATION GENE EFFECTS BASED ON JOINT SCALING TEST AND SOME GENETIC PARAMETERS IN FOUR MAIZE CROSSES 1-YIELD COMPONENTS

2019 ◽  
Vol 49 (2) ◽  
Author(s):  
B. H. Hadi
Keyword(s):  
Genetic Parameters ◽  
Genetic Variance ◽  
Block Design ◽  
Dominance Model ◽  
Chi Square ◽  
Gene Effects ◽  
Randomized Complete Block Design ◽  
Maize Grain ◽  
Allelic Interaction

The objective of this study to estimate the components of genetic variation, phenotypic (PCV) ,genotypic(GCV)  coefficient of variation, genetic gain and its percentage. An experiment was conducted at the field of Field Crop Dept.Coll. Agric.-Univ. Baghdad, using four crosses (FI01301 Rustico), (AntignaoHi39× Nostred), (Lo1391× Rustico) and (Rusticocangini× Rustico) which developed  from crossing of genetically different of six inbred lines for maize (Zae mays L.), introduced from Italy. Genetic parameters were estimated according to the Joint scaling test using the randomized complete block design with four replications. The components  of genetic variance; Additive and dominance of the maize grain yield and some trait, were estimated. The results showed that the values of Chi square were significant  for all the studied some traits  of all crosses, thus the simple additive – dominance model in four crosses exhibited lack of good fit  for all traits, indicates the role of non-allelic interaction. Dominance gene action was higher than additive for most traits. Therefore the hybridization would be more effective than population selection to improve these traits for these crosses.

scholarly journals THE EFFECT OF AN EXPERIMENTAL BOTTLENECK UPON QUANTITATIVE GENETIC VARIATION IN THE HOUSEFLY

Genetics ◽  
1986 ◽  
Vol 114 (4) ◽  
pp. 1191-1211 ◽  
Author(s):  
Edwin H Bryant ◽  
Steven A McCommas ◽  
Lisa M Combs
Keyword(s):  
Genetic Variation ◽  
Body Size ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Control Line ◽  
Additive Effects ◽  
Morphometric Traits ◽  
Complete Dominance ◽  
Quantitative Genetic ◽  
Principal Axes

ABSTRACT Effects of a population bottleneck (founder-flush cycle) upon quantitative genetic variation of morphometric traits were examined in replicated experimental lines of the housefly founded with one, four or 16 pairs of flies. Heritability and additive genetic variances for eight morphometric traits generally increased as a result of the bottleneck, but the pattern of increase among bottleneck sizes differed among traits. Principal axes of the additive genetic correlation matrix for the control line yielded two suites of traits, one associated with general body size and another set largely independent of body size. In the former set containing five of the traits, additive genetic variance was greatest in the bottleneck size of four pairs, whereas in the latter set of two traits the largest additive genetic variance occurred in the smallest bottleneck size of one pair. One trait exhibited changes in additive genetic variance intermediate between these two major responses. These results were inconsistent with models of additive effects of alleles within loci or of additive effects among loci. An observed decline in viability measures and body size in the bottleneck lines also indicated that there was nonadditivity of allelic effects for these traits. Several possible nonadditive models were explored that increased additive genetic variance as a result of a bottleneck. These included a model with complete dominance, a model with overdominance and a model incorporating multiplicative epistasis.

scholarly journals MASS SELECTION FOR POST-WEANING GROWTH IN SWINE: II. RESPONSE TO SELECTION

1971 ◽  
Vol 51 (2) ◽  
pp. 497-502 ◽  
Author(s):  
G. W. RAHNEFELD
Keyword(s):  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Average Daily Gain ◽  
Mass Selection ◽  
Realized Heritability ◽  
Response To Selection ◽  
Components Of Variance ◽  
Selection For ◽  
Seven Generations ◽  
Daily Gain

Recurrent mass selection for post-weaning average daily gain was practiced for seven generations in a population of Lacombe swine. Response to selection was positive, but the observed response was estimated to be only 0.33 of the predicted. The pooled estimate of additive genetic variance was 0.0013 ± 0.0002. Realized heritability was 0.126 ± 0.029. The pooled estimate of heritability obtained from components of variance and parent-offspring regression was 0.377 ± 0.058. Litter size was positively correlated with average daily gain (0.14 piglet per generation). No significant effects of selection in reducing additive genetic variance were observed.

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.

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