Selection strategies of segregant soybean populations for resistance to Asian rust

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.

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Accumulation of mutations affecting body weight in inbred mouse lines

Genetics Research ◽

10.1017/s0016672300033152 ◽

1995 ◽

Vol 65 (2) ◽

pp. 145-149 ◽

Cited By ~ 11

Author(s):

Armando Caballero ◽

Peter D. Keightley ◽

William G. Hill

Keyword(s):

Body Weight ◽

Maximum Likelihood ◽

Genetic Variance ◽

Inbred Mouse ◽

Additive Genetic Variance ◽

Selection Response ◽

Spontaneous Mutations ◽

Line Selection ◽

Divergence Estimates ◽

Mouse Lines

SummaryThe variation from spontaneous mutations for 6-week body weight in the mouse was estimated by selection from a cross of two inbred sublines, C57BL/6 and C57BL/10, separated about 50 years previously from the same inbred line. Selection was practised high and low for 12 generations from theF2, followed by one generation of relaxation. The lines diverged by approximately 1·7 g or 0·7 sd. The additive genetic variance was estimated in theF2by restricted maximum likelihood and from the selection response, and from this variance the mutational heritabilityhM2was estimated using the number of generations since divergence. Estimates ofhM2range from 0·08 to 0·10% depending on the method of analysis. These estimates are similar to those found for other species, but lower than other estimates for the mouse. It is concluded that substantial natural and, perhaps, artificial selection operated during the maintenance of the sublines.

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

Ciência e Agrotecnologia ◽

10.1590/s1413-70542012000200004 ◽

2012 ◽

Vol 36 (2) ◽

pp. 163-170 ◽

Cited By ~ 13

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.

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

Nigerian Journal of Animal Production ◽

10.51791/njap.v44i5.1545 ◽

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.

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Breeding and selection for high early season sugar content in a sugarcane (Saccharum spp. hybrids) improvement program

Australian Journal of Agricultural Research ◽

10.1071/ar9941569 ◽

1994 ◽

Vol 45 (7) ◽

pp. 1569 ◽

Cited By ~ 7

Author(s):

MC Cox ◽

DM Hogarth ◽

PB Hansen

Keyword(s):

Genetic Variance ◽

Recurrent Selection ◽

Sugar Content ◽

Additive Genetic Variance ◽

Breeding Population ◽

Cane Sugar ◽

Improvement Program ◽

Narrow Sense Heritability ◽

Saccharum Spp ◽

Early Season

A recurrent selection program for high early season commercial cane sugar (CCS) in sugarcane (Saccharum spp. hybrids) commenced in 1988. About 20 families (first clonal stage) and their parents are grown in two regions each year. Elite clones with high early CCS are selected and these are recycled into the breeding population with a short generation interval. Estimates of narrow-sense heritability from midparent-offspring regressions were moderate to high (0.6 or greater). Thus breeding for this trait using a large database of information available on early CCS characteristics of parental clones should be effective. Additive genetic variance (=2A) was more important than non-additive genetic variance.

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

10.53040/9789975347204.68 ◽

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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Genetic Control of O3 Sensitivity in a Cross Between Two Cultivars of Snap Bean

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.125.2.222 ◽

2000 ◽

Vol 125 (2) ◽

pp. 222-227 ◽

Cited By ~ 14

Author(s):

Richard A. Reinert ◽

Gwen Eason

Keyword(s):

Genetic Control ◽

Genetic Variance ◽

Additive Genetic Variance ◽

Phenotypic Variance ◽

Narrow Sense Heritability ◽

Snap Bean ◽

Reciprocal Crosses ◽

Blue Lake ◽

Environmental Component ◽

Variance Estimates

Identification of genetic control of ozone (O3) sensitivity is desirable for selection of plant cultivars which are indicators of O3 stress. A cross was made between two cultivars of snap bean (Phaseolus vulgaris L.), `Oregon 91' (P1) and `Wade Bush' (P2), an O3-sensitive and O3-insensitive cultivar, respectively. Ten genetic populations (generations), `Oregon 91' (P1), `Wade Bush' (P2), F1, F2, backcrosses to both parents, and all reciprocal crosses, were field planted in each of two summers and evaluated for injury to O3. Ozone responses for the reciprocal crosses were not significantly different for any generation, so injury ratings from the reciprocal crosses were combined for each generation to provide six populations (P1, P2, F1, F2, BC1, and BC2) for analysis. When components of genetic variation were estimated from the six generations, additive genetic variance was the most important component in the total genetic variance available, although dominance variance was also a significant component. There was an inconsistency in the magnitude and the direction of the factors contributing to the dominance effects and also a large environmental component making up the phenotypic variance. Estimates of broad-sense heritability and narrow-sense heritability were 60% and 44%, respectively. Results suggest that O3-sensitive and O3-insensitive selections could be screened and evaluated in an ambient O3 environment. Several generations will be necessary, however, to develop `Bush Blue Lake' type selections that vary only in sensitivity to O3.

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Using the best linear predictor (BLP) in the selection between and among half-sib progenies of the CMS-39 maize population

Brazilian Journal of Genetics ◽

10.1590/s0100-84551997000400021 ◽

1997 ◽

Vol 20 (4) ◽

pp. 683-690

Author(s):

Cleso Antônio Patto Pacheco ◽

José Ivo Ribeiro Júnior ◽

Cosme Damião Cruz

Keyword(s):

Variance Component ◽

Genetic Variance ◽

Additive Genetic Variance ◽

The Other ◽

Linear Predictor ◽

Selection Cycle ◽

Maize Population ◽

Best Linear Predictor ◽

Selection Of

Data of corn ear production (kg/ha) of 196 half-sib progenies (HSP) of the maize population CMS-39 obtained from experiments carried out in four environments were used to adapt and assess the BLP method (best linear predictor) in comparison with to the selection among and within half-sib progenies (SAWHSP). The 196 HSP of the CMS-39 population developed by the National Center for Maize and Sorghum Research (CNPMS-EMBRAPA) were related through their pedigree with the recombined progenies of the previous selection cycle. The two methodologies used for the selection of the twenty best half-sib progenies, BLP and SAWHSP, led to similar expected genetic gains. There was a tendency in the BLP methodology to select a greater number of related progenies because of the previous generation (pedigree) than the other method. This implies that greater care with the effective size of the population must be taken with this method. The SAWHSP methodology was efficient in isolating the additive genetic variance component from the phenotypic component. The pedigree system, although unnecessary for the routine use of the SAWHSP methodology, allowed the prediction of an increase in the inbreeding of the population in the long term SAWHSP selection when recombination is simultaneous to creation of new progenies.

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Narrow-sense heritability estimation of complex traits using identity-by-descent information

10.1101/164848 ◽

2017 ◽

Author(s):

Luke M. Evans ◽

Rasool Tahmasbi ◽

Matthew Jones ◽

Scott I. Vrieze ◽

Gonçalo R. Abecasis ◽

...

Keyword(s):

Complex Traits ◽

Genetic Variance ◽

Additive Genetic Variance ◽

Fundamental Parameter ◽

Last Common Ancestor ◽

Narrow Sense ◽

Narrow Sense Heritability ◽

Heritability Estimation ◽

Causal Variants ◽

Heritability Estimates

ABSTRACTHeritability is a fundamental parameter in genetics. Traditional estimates based on family or twin studies can be biased due to shared environmental or non-additive genetic variance. Alternatively, those based on genotyped or imputed variants typically underestimate narrow-sense heritability contributed by rare or otherwise poorly-tagged causal variants. Identical-by-descent (IBD) segments of the genome share all variants between pairs of chromosomes except new mutations that have arisen since the last common ancestor. Therefore, relating phenotypic similarity to degree of IBD sharing among classically unrelated individuals is an appealing approach to estimating the near full additive genetic variance while avoiding biases that can occur when modeling close relatives. We applied an IBD-based approach (GREML-IBD) to estimate heritability in unrelated individuals using phenotypic simulation with thousands of whole genome sequences across a range of stratification, polygenicity levels, and the minor allele frequencies of causal variants (CVs). IBD-based heritability estimates were unbiased when using unrelated individuals, even for traits with extremely rare CVs, but stratification led to strong biases in IBD-based heritability estimates with poor precision. We used data on two traits in ~120,000 people from the UK Biobank to demonstrate that, depending on the trait and possible confounding environmental effects, GREML-IBD can be applied successfully to very large genetic datasets to infer the contribution of very rare variants lost using other methods. However, we observed apparent biases in this real data that were not predicted from our simulation, suggesting that more work may be required to understand factors that influence IBD-based estimates.

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Efficiencies of Clonally Replicated and Seedling Testing for Spruce Breeding and Deployment Strategies

Silvae Genetica ◽

10.1515/sg-2009-0038 ◽

2009 ◽

Vol 58 (1-6) ◽

pp. 292-300

Author(s):

Y. H. Weng ◽

Y. S. Park ◽

D. Simpson ◽

T. J. Mullin

Keyword(s):

Genetic Variance ◽

Gene Diversity ◽

Additive Genetic Variance ◽

Seed Orchard ◽

Narrow Sense ◽

Family Selection ◽

Narrow Sense Heritability ◽

Additive Variance ◽

Clonal Seed Orchard ◽

Seedling Test

AbstractGenetic gains based on a genetic test using clonal replicates were compared to those based on a test using seedlings at the same gene diversity and testing effort levels using POPSIM™ Simulator. Three testing and deployment strategies targeting for white spruce (P. glauca [Moench] Voss) and black spruce (P. mariana (Mill.) B.S.P.) in New Brunswick were compared: seedling test with clonal seed orchard deployed as seedlings (CSO_ST), clonally replicated test with clonal seed orchard deployed as seedlings (CSO_CRT), and clonally replicated test deployed as a clone mix (MVF). The breeding populations (BP) were formed by balanced within-family selection and the production populations (PP) were selected by strong restriction on relatedness, i.e., no parent in common. Compared to the seedling test, the clonally replicated test resulted in faster accumulation of additive effects but quicker loss of additive variance in the BP, and this is particular true in the case of lower narrow-sense heritability or less non-additive genetic variance. The quicker loss in BP additive variance was overcompensated for by its faster accumulation in BP additive effect, resulting in higher gain in the clonally replicated test based PPs. Compared to the CSO_ST, the gain superiority of the CSO_CRT increased with generations, decreasing narrow-sense heritability or reducing the amount of non-additive variance. Implementing MVF was the most effective in terms of gain in most simulated cases and its superiority over the CSO_ST increased with generations, decreasing narrowsense heritability, or increasing non-additive genetic variance. Overall results demonstrated significant advantages of using clonally replicated test both for BP advancement and PP selection in most of the scenarios, suggesting that clonally replicated test should be incorporated into current spruce breeding strategies.

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Additive and Dominance Genomic Analysis for Litter Size in Purebred and Crossbred Iberian Pigs

Genes ◽

10.3390/genes13010012 ◽

2021 ◽

Vol 13 (1) ◽

pp. 12

Author(s):

Houssemeddine Srihi ◽

José Luis Noguera ◽

Victoria Topayan ◽

Melani Martín de Hijas ◽

Noelia Ibañez-Escriche ◽

...

Keyword(s):

Litter Size ◽

Genetic Variance ◽

Mixed Model ◽

Additive Genetic Variance ◽

Genetic Correlations ◽

Genomic Analysis ◽

Gxe Interaction ◽

Genomic Regions ◽

Additive Genetic Effects ◽

Selection Of

INGA FOOD S. A., as a Spanish company that produces and commercializes fattened pigs, has produced a hybrid Iberian sow called CASTÚA by crossing the Retinto and Entrepelado varieties. The selection of the parental populations is based on selection criteria calculated from purebred information, under the assumption that the genetic correlation between purebred and crossbred performance is high; however, these correlations can be less than one because of a GxE interaction or the presence of non-additive genetic effects. This study estimated the additive and dominance variances of the purebred and crossbred populations for litter size, and calculated the additive genetic correlations between the purebred and crossbred performances. The dataset consisted of 2030 litters from the Entrepelado population, 1977 litters from the Retinto population, and 1958 litters from the crossbred population. The individuals were genotyped with a GeneSeek® GGP Porcine70K HDchip. The model of analysis was a ‘biological’ multivariate mixed model that included additive and dominance SNP effects. The estimates of the additive genotypic variance for the total number born (TNB) were 0.248, 0.282 and 0.546 for the Entrepelado, Retinto and Crossbred populations, respectively. The estimates of the dominance genotypic variances were 0.177, 0.172 and 0.262 for the Entrepelado, Retinto and Crossbred populations. The results for the number born alive (NBA) were similar. The genetic correlations between the purebred and crossbred performance for TNB and NBA—between the brackets—were 0.663 in the Entrepelado and 0.881 in Retinto poplulations. After backsolving to obtain estimates of the SNP effects, the additive genetic variance associated with genomic regions containing 30 SNPs was estimated, and we identified four genomic regions that each explained > 2% of the additive genetic variance in chromosomes (SSC) 6, 8 and 12: one region in SSC6, two regions in SSC8, and one region in SSC12.

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