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.

scholarly journals Selection strategies of segregant soybean populations for resistance to Asian rust

2009 ◽  
Vol 44 (11) ◽  
pp. 1452-1459 ◽  
Author(s):  
Aliny Simony Ribeiro ◽  
José Francisco Ferraz de Toledo ◽  
Magno Antonio Patto Ramalho
Keyword(s):  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Infected Leaf ◽  
Good Resistance ◽  
Narrow Sense Heritability ◽  
Growing Seasons ◽  
Selection Strategies ◽  
Line Selection ◽  
Soybean Resistance ◽  
Selection Of

The objective of this work was to identify the best selection strategies for the more promising parental combinations to obtain lines with good resistance to soybean Asian rust (Phakopsora pachyrhizi). Two experiments were carried out in the field during the 2006/2007 and 2007/2008 growing seasons, to determine the percentage of infected leaf area of individual plants of five parents and their segregant F2 and F3 populations. The data obtained indicates that additive genetic variance predominates in the control of soybean resistance to Asian rust, and that the year and time of assessment do not significantly influence the estimates of the genetic parameters obtained. The narrow-sense heritability (h²r) ranged from 23.12 to 55.83%, and indicates the possibility of successful selection of resistant individuals in the early generations of the breeding program. All the procedures used to select the most promising populations to generate superior inbred lines for resistance to P. pachyrhizi presented similar results and identified the BR01-18437 x BRS 232 population as the best for inbred line selection.

scholarly journals Estimate of genetic parameters and predicted gains with early selection of physic nut families

2012 ◽  
Vol 36 (2) ◽  
pp. 163-170 ◽  
Author(s):  
Bruno Galvêas Laviola ◽  
Alexandre Alonso Alves ◽  
Fábio de Lima Gurgel ◽  
Tatiana Barbosa Rosado ◽  
Rhayanne Dias Costa ◽  
...  
Keyword(s):  
Grain Yield ◽  
Genetic Parameters ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Biodiesel Production ◽  
Early Selection ◽  
Physic Nut ◽  
Genetic Gains ◽  
Canopy Volume ◽  
Selection Of

An initial evaluation of early selection of physic nut genotypes based on phenotypic data is presented. In order to predict the genetic gains with early selection, genetic parameters, e.g. additive genetic variance, were first obtained for grain yield along with other numerous traits. The results demonstrated that additive genetic variance exists not only for grain yield, which is considered to be the most important trait for oil and biodiesel production, but also for numerous other traits. The predicted genetic gains for grain yield, considering the selection of the 30, 20, 10 and 5 best families in the second crop year are respectively, 40.47, 48.43, 61.78 and 70.28%. With the selection of highly yielding physic nut genotypes indirectly genotypes with enhanced volume would be also selected, because yield exhibits moderate to high genetic correlations with height e canopy volume. The results here presented demonstrate the potential of the population gathered in the Brazilian physic nut germplasm bank for genetic breeding purposes and that superior physic nut families can be selected with high accuracy based on the evaluation of its second crop.

Quantitative inheritance studies in sugar-cane. I. Estimation of variance components

1971 ◽  
Vol 22 (1) ◽  
pp. 93 ◽  
Author(s):  
DM Hogarth
Keyword(s):  
Factorial Design ◽  
Variance Components ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
The Other ◽  
Quantitative Inheritance ◽  
Genetic Determination ◽  
Nested Design ◽  
Dominance Genetic Variance ◽  
Estimation Of Variance

Two experiments in quantitative genetics were conducted, one based on a nested design in lattice squares and the other on a factorial design in a balanced lattice. Lattice designs were found to be suitable for genetic experiments if a large number of crosses was involved, but posed some problems in partitioning the sum of squares for treatments. The factorial design was considered preferable to the nested design, although neither design permitted estimation of epistatic variances which, therefore, were assumed to be negligible. Additive genetic variance was found to be more important than dominance genetic variance for most characters. However, most estimates of genetic variance lacked precision in spite of the use of large, precise experiments, which illustrated the difficulty in obtaining estimates of variance components with adequate precision. The validity of assumptions made for these analyses is discussed. The effect of competition was studied and estimates of heritability and degree of genetic determination were determined.

scholarly journals Variance Component Analysis of Parthenocarpic Character in a Processing Cucumber (Cucumis sativus L.) population

HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 881A-881
Author(s):  
Zhanyong Sun* ◽  
Richard L. Lower ◽  
Jack E. Staub
Keyword(s):  
Cucumis Sativus ◽  
Variance Component ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Component Analysis ◽  
Variance Component Analysis ◽  
Individual Plant ◽  
Normal Leaf ◽  
Dominance Genetic Variance ◽  
Plant Basis

The incorporation of genes for parthenocarpy (production of fruit without fertilization) has potential for increasing yield in pickling cucumber (Cucumis sativus L.). The inheritance of parthenocarpy in cucumber is not well understood, and thus a genetic analysis was performed on F3 cross-progeny resulting from a mating between the processing cucumber inbred line 2A (P1, gynoecious, parthenocarpic, indeterminate, normal leaf) and Gy8 (P2, gynoecious, non-parthenocarpic, indeterminate, normal leaf). A variance component analysis was performed to fruit yield data collected at two locations (designated E-block and G-block) at Hancock, WI in 2000. The relative importance of additive genetic variance compared to dominance genetic variance changed across environments. The additive genetic variance was 0.5 and 4.3 times of dominance genetic variance in E-block and G-block, respectively. The estimated environmental variance accounted for ≈90% of the total phenotypic variance on an individual plant basis in both locations. Narrow-sense heritability estimated on an individual plant basis ranged from 0.04 (E-block) to 0.12 (G-block). Broad-sense heritability estimated on an individual plant basis ranged from 0.12 (E-block) to 0.15 (G-block). The minimum number of effective factors controlling parthenocarpy was estimated to range between 5 (G-block) to 13 (E-block). These results suggest that the response to direct selection of individual plants for improving parthenocarpy character will likely be slow and difficult. Experiment procedures that minimize the effect of environment on the expression of parthenocarpy will likely maximize the likelihood of gain from selection.

scholarly journals Combining ability analysis in near homozygous lines of okra [Abelmoschus esculentus (L.) Moench] for yield and yield attributing parameters

2017 ◽  
Vol 9 (1) ◽  
pp. 324-331
Author(s):  
Y. A. Lyngdoh ◽  
R. Mulge ◽  
A. Shadap ◽  
Jogendra Singh ◽  
Seema Sangwan
Keyword(s):  
Combining Ability ◽  
Genetic Variance ◽  
Gene Action ◽  
Additive Genetic Variance ◽  
Total Yield ◽  
Fruit Weight ◽  
Additive Gene Action ◽  
Combining Ability Analysis ◽  
Additive Gene ◽  
Number Of Branches

Line × tester analysis was carried out with the objective of identifying the good combiners and to decide the breeding strategies for developing potential and productive genotypes or cultivars. Parents and hybrids differed significantly for GCA and SCA effects for all the characters respectively. Specific combining ability (SCA) variance was higher than the general combining ability (GCA) variance which shows the predominance of non-additive gene action for the improvement of all the characters studied. The parents and crosses having highest and significant GCA and SCA effects viz., KO-18 (13.69), KO-6 (9.54) and KO-2 × Parbhani Kranti (19.28) for plant height; KO-12 (0.34), KO-14 (0.19) and KO-5 × V5 (0.60) for number of branches per plant; KO-14 (-0.66) and KO-15 × Arka Anamika(-1.66) for days to first flowering; KO-1(1.10), Arka Anamika (0.46) and KO-9 × VRO-5 (3.28) for fruit length; KO-7 (7.91), VRO-5(1.68) and KO-18 × VRO-6 (8.64) for average fruit weight; KO-2 (1.18) and KO-17 × Arka Anamika (2.80) for number of fruits per plant; KO-9(0.05), VRO-6 (0.01) and KO-11 × VRO-6 (0.10) for total yield per plant were identified as good general and specific combiners. The results establish the worth of heterosis breeding for effective usage of non-additive genetic variance in okra.

scholarly journals Estimation of variance components for bodyweight of grasscutters using expectation maximization algorithm of restricted maximum likelihood

2020 ◽  
Vol 44 (5) ◽  
pp. 5-8
Author(s):  
I. Udeh
Keyword(s):  
Body Weight ◽  
Maximum Likelihood ◽  
Expectation Maximization ◽  
Variance Components ◽  
Genetic Variance ◽  
Phenotypic Variability ◽  
Additive Genetic Variance ◽  
Expectation Maximization Algorithm ◽  
Estimation Of Variance ◽  
Selection Of

The objective of this study was to estimate the variance components and heritability of bodyweight of grasscutters at 4, 6 and 8 months of age using EM algorithm of REML procedures. The data used for the study were obtained from the bodyweight records of 20 grasscutters from four families at 4, 6 and 8 months of age. The heritability of bodyweight of grasscutters at 4, 6 and 8 months of age were 0.14, 0.10 and 0.12 respectively. This implies that about 10 – 14 % of the phenotypic variability of body weight in this grasscutter population was accounted by additive genetic variance while environmental and gene combination variance made a larger contribution. The implication is that selection of grasscutters in this population should not be based on the information on the animals alone but also information fromits relatives.

scholarly journals Selection of half-sib families of creole melon (Cucumis melo L.) on the Ecuadorian coast

2019 ◽  
Vol 13 (2) ◽  
pp. 178-185
Author(s):  
Francisco Espinosa ◽  
Franco Alirio Vallejo ◽  
Lauden Rizzo
Keyword(s):  
Block Design ◽  
Fruit Weight ◽  
Soluble Solids ◽  
Genetic Progress ◽  
Randomized Complete Block Design ◽  
Sib Families ◽  
High Production ◽  
Cucumis Melo L ◽  
Fruit Diameter ◽  
Selection Of

The creole melon cantaloupe is a horticultural species, whose fruits are used for human nutrition. However, no research has been reported on their genetic variability for starting breeding processes. The objective of this study was to take advantage of the variability of creole melons for genetic improvement. 20 creole melon half-sib families were selected and evaluated for production characteristics and fruit quality in order to obtain improved populations. The study was carried out in Palenque canton, Ecuador. Seeds from 20 half-sib families were used, arranged in a randomized complete block design with three replications. The differences between the families were significant for all the studied characteristics. Family 93 presented higher averages for fruit weight, fruit diameter and production (per hectare), and family 196 did so for soluble solids. The phenotypic correlations were positive and significant between the fruit weight and fruit diameter, fruit length, pulp thickness, fruit cavity, soluble solids and production. The coefficients of genetic variation, in general, were lower than the coefficients of environmental variation. The estimates of heritability broadly had a moderate magnitude (30-60%) for the 10 evaluated characteristics, and the magnitude of the expected genetic progress was low (<10%) for the fruit weight, production, and soluble solids, so the selection for high production should focus on fruit weight and soluble solids.

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 Variabilitatea şi heritabilitatea vigorii boabelor de grâu comun la interacţiunea cu Drechslera Sorokiniana

2020 ◽  
Author(s):  
Galina Lupascu ◽  
◽  
Svetlana Gavzer ◽  
Keyword(s):  
Common Wheat ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Broad Sense ◽  
Genetic Progress ◽  
Vigor Index ◽  
Seedling Length ◽  
Selection Of

The article presents data on the effects of the interaction of common wheat with the fungus Drechslera sorokiniana on grain vigor. Its differentiated action on germination and seedling length (LP) was found. The vigor index (VI) depended more on LP (r = 0.90 *) than on the germination 278 level (r = 0.52 *, p≤0.05). The coefficient of heritability in the broad sense (h2) was 71.3% for LP and 60.1% – for VI. The association of h2 and genetic progress with high values reveals the pronounced contribution of additive genetic variance in the control of the vigor index, which offers increased opportunities in the selection of wheat plants resistant to this pathogen in restricted terms.

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