scholarly journals Heritability estimation in early generations of two-way crosses in soybean

Bragantia ◽  
2008 ◽  
Vol 67 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Marcelo Marchi Costa ◽  
Antonio Orlando Di Mauro ◽  
Sandra Helena Unêda-Trevisoli ◽  
Nair Helena Castro Arriel ◽  
Ivana Marino Bárbaro ◽  
...  
Keyword(s):  
Genetic Parameters ◽  
Genetic Variance ◽  
Selection Process ◽  
Broad Sense ◽  
Selection Methods ◽  
Narrow Sense ◽  
Breeding Programs ◽  
Heritability Estimation ◽  
The Family ◽  
Simple Selection

The estimation of genetic parameters, especially in early generations, is very useful for directing the selection process in breeding programs. The present research was undertaken to estimate heritabilities in the broad sense, narrow sense and using parent-offspring regression in F3 soybean populations from six two-way crosses, originated from the Soybean Breeding Program of Faculdade de Ciências Agrárias e Veterinárias (UNESP), Jaboticabal campus. It was used the family design with common checks located ten plots apart. It was observed highly significant differences among families. The experimental coefficient of variation (CVe), the CVg/CVe ratio and the heritability showed wide variation among traits, being the highest values found for number of pods, number of seeds and grain yield, making evident the existence of variance to be exploited by breeding. The estimation of the heritability coefficients in the broad sense, narrow sense and by regression were close in most of the situations, showing that the largest part of genetic variance is of additive nature, in which simple selection methods can lead to satisfactory genetic gains.

scholarly journals Genetic variance and heritability estimation of hybridized pepper plants (Capsicum annuum L.) F2 progeny for begomovirus resistance in growth stage

2022 ◽  
Vol 951 (1) ◽  
pp. 012103
Author(s):  
E Kesumawati ◽  
Sabaruddin ◽  
E Hayati ◽  
N Hadisah ◽  
R Hayati ◽  
...  
Keyword(s):  
Growth Stage ◽  
Genetic Variance ◽  
Broad Sense ◽  
Phenotypic Variance ◽  
Broad Sense Heritability ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Training Centre ◽  
Tertiary Branch ◽  
Heritability Estimation

Abstract Pepper is widely cultivated as a condiment and cash crop in Indonesia. However, Pepper yellow leaf curl disease (PepYLCD) caused by begomovirus is currently seriously affect the domestic pepper production. Breeding for begomovirus resistance material by crossing is currently necessary to overcome the constraint. The present study is aimed to determine the resistance of pepper (C. annuum) plants F2 progenies to begomovirus infection in the growth stage. Two local C. annuum accessions, BaPep-5 as a resistance donor for pepy-1 begomovirus resistance gene (locally called Perintis) and BaPep-4 as a susceptible parent (locally called Kencana) were crossed to generate F2 progenies. The research was conducted in Agricultural Extension Training Centre (BLPP) Saree and Horticulture Laboratory of Syiah Kuala University from February to July 2020. 500 F2 progenies were transplanted to the field along with 15 plants of each parent as control. The result suggested that plant height and crown width had the highest broad sense heritability value, whereas the dichotomous height, stem diameter, secondary branch, and tertiary branch had the lowest broad sense heritability value. Coefficient of genetic variance and coefficient of phenotypic variance from overall characteristics were relatively low which suggest the narrow sense to slightly narrow sense heritability.

scholarly journals A Genome-Wide Association Analysis Reveals Epistatic Cancellation of Additive Genetic Variance for Root Length in Arabidopsis thaliana

2014 ◽  
Author(s):  
Jennifer Lachowiec ◽  
Xia Shen ◽  
Christine Queitsch ◽  
Örjan Carlborg
Keyword(s):  
Arabidopsis Thaliana ◽  
Candidate Genes ◽  
Root Length ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Broad Sense ◽  
Genome Wide Association ◽  
Broad Sense Heritability ◽  
Narrow Sense ◽  
Genome Wide

Efforts to identify loci underlying complex traits generally assume that most genetic variance is additive. Here, we examined the genetics of Arabidopsis thaliana root length and found that the narrow-sense heritability for this trait was statistically zero. This low additive genetic variance likely explains why no associations to root length could be found using standard additive-model-based genome-wide association (GWA) approaches. However, the broad-sense heritability for root length was significantly larger, and we therefore also performed an epistatic GWA analysis to map loci contributing to the epistatic genetic variance. This analysis revealed four interacting pairs involving seven chromosomal loci that passed a standard multiple-testing corrected significance threshold. Explorations of the genotype-phenotype maps for these pairs revealed that the detected epistasis cancelled out the additive genetic variance, explaining why these loci were not detected in the additive GWA analysis. Small population sizes, such as in our experiment, increase the risk of identifying false epistatic interactions due to testing for associations with very large numbers of multi-marker genotypes in few phenotyped individuals. Therefore, we estimated the false-positive risk using a new statistical approach that suggested half of the associated pairs to be true positive associations. Our experimental evaluation of candidate genes within the seven associated loci suggests that this estimate is conservative; we identified functional candidate genes that affected root development in four loci that were part of three of the pairs. In summary, statistical epistatic analyses were found to be indispensable for confirming known, and identifying several new, functional candidate genes for root length using a population of wild-collected A. thaliana accessions. We also illustrated how epistatic cancellation of the additive genetic variance resulted in an insignificant narrow-sense, but significant broad-sense heritability that could be dissected into the contributions of several individual loci using a combination of careful statistical epistatic analyses and functional genetic experiments.

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

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.

scholarly journals Sample size for family evaluation in potato breeding programs

2006 ◽  
Vol 30 (2) ◽  
pp. 277-282 ◽  
Author(s):  
Maria Cristina Duarte Rios Diniz ◽  
César Augusto Brasil Pereira Pinto ◽  
Eduardo de Souza Lambert
Keyword(s):  
Potato Breeding ◽  
Genetic Variance ◽  
Correlation Coefficients ◽  
Small Sample ◽  
Family Selection ◽  
Breeding Programs ◽  
Lattice Design ◽  
Experimental Variation ◽  
The Family ◽  
Tuber Specific Gravity

Clonal families from a broad genetic base population in the Potato Breeding Program at the Universidade Federal de Lavras (UFLA), Brazil, were used in this trials. Twenty-five families were assessed in a 5 x 5 triple lattice design. Each plot consisted of 30 clones distributed in three rows of ten plants. Tuber yield per plant, percentage of large tubers, mean weight of large tubers, mean medium-sized tuber weight and tuber specific gravity were measured. Three hundred experiments were simulated varying the family sizes from three to 90 clones. The coefficients of experimental variation (CVe), the coefficients of genetic variation (CVg), heritabilities for family mean and the CVg/CVe ratio were estimated. Genetic parameters were stabilized with family sizes as small as six clones, depending on the trait. This indicates that the families can be adequately represented by a small sample of clones. Using the maximum curvature method it is possible to conclude that approximately 30 clones would be sufficient to represent each family, even for traits with the highest CVe. The genetic variance within family was greater than the genetic variance among families for all traits, indicating a favorable potential for within family selection. The correlation coefficients of the family means with the 5%, 10%, 15% and 20% best clones from each family, considering the five traits assessed, were always high, meaning that within the best families generally are the best clones.

scholarly journals ESTIMATION OF HETEROSIS AND GENETIC PARAMETERS FOR SOME FLOWERING AND VEGETATIVE TRAITS IN MAIZE USING THE DIALLEL CROSS METHOD

2015 ◽  
Vol 2 (2) ◽  
pp. 157-166
Author(s):  
Maamoun Ahmed Abdel-Moneam ◽  
M.S. Sultan ◽  
S.E. Sadek ◽  
M.S. Shalof
Keyword(s):  
Plant Height ◽  
Genetic Parameters ◽  
Diallel Cross ◽  
Wilt Disease ◽  
Broad Sense ◽  
Narrow Sense ◽  
Planting Dates ◽  
Vegetative Traits ◽  
Heritability Estimates ◽  
Combined Data

A diallel cross among inbred lines of maize (Zea mays L.) with medium maturity and an evaluation to estimate the genetic parameters for days to 50 % tasseling, days to 50% silking, plant and ear heights, resistance to late wilt disease, ear position were carried out. Mean squares were significant for all of the studied traits. Hybrids mean squares were highly significant for the all studied traits under both planting dates and combined analysis, except days to 50% silking. Indicating that the hybrids performance differed from planting date to another. The highest negative heterosis effect was exhibited by cross P5XP2, P6 x P2, P2 x P6, P3 x P5and P3 x P6 over better parent, crosses P5 x P2 , P6 x P2 and P2 x P6 over mid- parents and crosses P5 x P1, P3 x P2 , P4 x P2 ,P5 x P2 , P6 x P2 , P2 x P6 , P3 x P5 and P3 x P6 over check varieties for tasseling date. For days to 50% silking showed that highest significant and negative heterotic effect was exhibited by crosses P6 x P1, P6 x P2, P2 x P6, P4 x P3 and P3 x P6 over mid- parents and all crosses had highly significant and negative heterosis over check varieties, the highest significant and negative heterotic effects were reported by P6 x P1, P6 x P2, P2 x P6, P4x P3 and P3 x P6 over mid- parents and, P3 x P2, P4 x P2 reciprocal, P5 x P2, P6 x P2 and P3 x P6 over check varieties, The highest significant and positive heterotic effect was exhibited by P3 x P5 and P4 x P3 (40.35 and 37.46%) over better-parent and mid-parents respectively, P4 x P2 (13.93%) highest negative significant heterotic effect over check varieties for plant height. For ear height cross P4—P3 showed maximum negative heterosis over check varieties. For resistance to late wilt disease results regarding significant for crosses P1 x P3,P3 x P1,P1 x P4 ,P4 x P1,P1—P5 and P5 x P1 (1.522%) over mid-parents , indicating that these crosses are the best combinations for resistance to late wilt disease. For ear position , 25 crosses show highly significant and negative heterosis over better-parent value for ear position ,P4 x P3 showed maximum negative heterosis over better-parent and over mid-parents . Seven crosses show highly significant and negative heterosis over check varieties value for ear position, P6 x P4 (-8.92%) showed maximum negative heterosis over check varieties. Heritability estimates in broad sense were generally higher at combined data. In the combined data percentage of heritability in the narrow sense for studied traits ranged from 20% for plant height to 46% for days to 50% tasseling or silking. Heritability estimates were low for plant and ear heights in narrow sense (20% and 28%) and the same in broad sense (29% and 38%), respectively. Heritability estimates in broad sense were medium (29% -64%) of all studied traits. Hence it could be concluded that these crosses may be useful for improving maize grain yield program.

scholarly journals Evaluation of Brassica Juncea Germplasm through heritability estimation and correlation analysis

2017 ◽  
pp. 22-25
Author(s):  
Fawad Ali ◽  
Bakhat Hussain ◽  
Javed Ali, Mehran Ayoob Tunio
Keyword(s):  
Correlation Analysis ◽  
Brassica Juncea ◽  
Seed Yield ◽  
Genetic Parameters ◽  
Broad Sense ◽  
Yield Traits ◽  
Broad Sense Heritability ◽  
Heritability Estimation ◽  
The University ◽  
Pod Length

The experimental material was planted at the University of Agriculture, Peshawar to estimate genetic parameters of heritability and correlation for yield traits of indigenous Brassica Juncea genotypes. RCB design with three replications was used to sow 20 Brassica genotypes. Highly significant genetic variations were obtained among studied parameters. Days to half flowering revealed positive associations with primary branches per plant (r= 0.337**). Primary branches per plant was positively correlated with pod length (r= 0.407**), seed per pod (r= 0.418**) seed yield per plant (r= 0.479**). Similarly, pod length showed positive correlation with seed per pod (r= 0.324*) and seed yield per plant (r= 0.331**), while seed per pod was positively correlated with seed yield per plant (r= 0.878**). Highest broad-sense heritability was recorded for seed yield per plant (0.97), while lowest heritability was estimated for primary branches per plant (0.46).

scholarly journals Evaluation of Variance Components and Genetic Parameters in F1 Progenies of Coffea canephora Pierre x C. congensis Froehner

2021 ◽  
pp. 12-23
Author(s):  
Kouassi M. Ouattara ◽  
Yapo A. Antoine ◽  
Nguetta A. Simon-Pierre ◽  
Okoma M. Pamela ◽  
Gba Kossia M. Karine ◽  
...  
Keyword(s):  
Genetic Parameters ◽  
Block Design ◽  
Diploid Species ◽  
Coffea Canephora ◽  
Broad Sense ◽  
High Yield ◽  
Narrow Sense ◽  
Vegetative Traits ◽  
Additive Gene

The diploid species Coffea congensis is of interest in improving the organoleptic quality of                        C. canephora. F1 crosses of C. canephora x C. congensis named Congusta in 3 x 5 factorial design have been carried out. The work aimed to assess the genetic parameters in the hybrids in order to integrate them into the selection schemes under way in Côte d'Ivoire.  The experimental design was a randomized complete block design. Each cross was represented by a minimum of 29 plants and a maximum of 55 plants. The spacing used was 3 x 1.5 m. Male genotypes C. congensis brought little improvement in offspring regardless of their insignificant additive gene effect in the hybrids. Low heritabilities were found for vegetative vigor traits DICO, GAT and NPLA ranging from 0.13 to 0.23 in the narrow sense and from 0.18 to 0.32 in the broad sense. For production, the narrow sense heritabilities were stable during the first three years of harvest with values ​​between 0.23 and 0.25 whereas the broad sense heritability was irregular. The estimation GCA and SCA showed that all the traits except RCAR had ratio between both effects above 1. The study of correlations between traits showed insignificant correlations between production and vegetative traits, with coefficients below 0.30. However, The selection of 83 high-producing trees from 14 out of 15 studied families make it possible to create good vegetative trees linked to high yield.

scholarly journals Genetic Analysis of Flower Size and Production in Diploid Rose

2017 ◽  
Vol 142 (4) ◽  
pp. 306-313 ◽  
Author(s):  
Shuyin Liang ◽  
Xuan Wu ◽  
David Byrne
Keyword(s):  
Heat Stress ◽  
Genetic Variance ◽  
Dry Weight ◽  
Broad Sense ◽  
Flower Size ◽  
Narrow Sense ◽  
Different Seasons ◽  
Flower Diameter ◽  
Selection For ◽  
Selection Of

This project examined rose (Rosa ×hybrida) performance by measuring flower size and flower numbers per inflorescence in spring, summer, and fall seasons (mean temperatures 21.7, 30.0, and 18.1 °C, respectively) in interrelated rose populations. Populations and progeny differed in flower size as expected. Heat stress in the summer season decreased flower diameter (18%), petal number (17% to 20%), and flower dry weight (32%). Analysis of variance (ANOVA) showed a significant population/progeny × heat stress interaction for flower diameter indicating that rose genotypes responded differentially to heat stress. Flower size traits had moderate low to moderate narrow-sense (0.38, 0.26–0.33, and 0.53 for flower diameter, petal number, and flower dry weight, respectively) and moderately high to high broad-sense (0.70, 0.85–0.91, and 0.88 for flower diameter, petal number, and flower dry weight, respectively) heritability. Genotype × environment (G × E) variance (population/progeny × heat stress) for flower diameter accounted for ≈35% of the total variance in the field experiment indicating that heat stress had moderate differential genotypic effects. However, the genetic variance was several fold greater than the G × E variance indicating selection for flower size would be effective in any season but for the selection of a stable flower size (heat tolerant) rose genotype, selection would be required in both the cool and warm seasons. Seasonal differences in flower productivity of new shoots did not appear related to heat stress but rather to the severity of pruning conducted in the different seasons. The number of flowers produced on the inflorescence had moderate narrow-sense (h2 = 0.43) and high broad-sense (H2 = 0.75) heritability with a moderate genotype × pruning effect that explained about 36% of the variance.

scholarly journals Role of Some Genetic Parameters on Breeding Work for Resistance to Pre-Harvest

2012 ◽  
Vol 69 (1) ◽  
Author(s):  
Lupu Nicolae ◽  
Vasile Moldovan ◽  
Rozalia Kadar ◽  
Ionut Racz
Keyword(s):  
Genetic Parameters ◽  
Phenotypic Expression ◽  
Broad Sense ◽  
Quantitative Character ◽  
Broad Sense Heritability ◽  
Narrow Sense ◽  
Falling Number ◽  
Narrow Sense Heritability ◽  
Gene Effects

For wheat ( Triticum aestivum ), periods of prolonged rainfall and high humidity after the grain has ripened and before it can be harvested can contribute to, so called pre-harvest sprouting (PHS), which can be considered as a premature germination. PHS can be defined a complex quantitative character having two important components: sprouting score and falling number. The two these components are controlled by gene effects which are predominant of additive nature. Our research have been conducted on parental, F 1, F2, backcross generations means, from 4 cyclic crosses with common parents differing in their reaction to PHS and falling number. Broad sense heritability coefficients for PHS score showed high values in the case of majority hybrids that indicate the important role of genotype in phenotypic expression of reaction to sprouting. Concerning to falling number, broad sense heritability coefficients had smaller values. For wheat as a self pollinated crop, is preferable to be used narrow sense heritability which reflects additive genetic contribution to phenotypic expression of sprouting or falling number, because only additive gene effects can be fixed to progeny. When PHS score, or falling number have high values for narrow sense heritability (higher 50), is recommended the beginning of selection in F 2 and in these cases can be successful applied pedigree selection. Concluding, high heritabilities associated with other genetic parameters can be important tools at hand of breeders. They indicated that wheat selection for PHS tolerance or falling number would be effective in populations involving crosses of sensitive and tolerant parents.

Genetic control of rooting ability of stem cuttings from loblolly pine

1990 ◽  
Vol 20 (9) ◽  
pp. 1361-1368 ◽  
Author(s):  
G. S. Foster
Keyword(s):  
Genetic Control ◽  
Loblolly Pine ◽  
Genetic Variance ◽  
Broad Sense ◽  
Mass Selection ◽  
Environment Interaction ◽  
Stem Cuttings ◽  
Narrow Sense ◽  
Gene Effects ◽  
Selection Of

Stem cuttings from 546 loblolly pine (Pinustaeda L.) seedlings were set for rooting during each of three separate trials over time. The seedlings arose from 54 full-sib families derived from four factorial mating designs. Phenotypic variation in rooting percentage was partitioned into genetic variance, environmental variance, and genotype × environment interaction variance. Virtually all genetic variance was due to additive gene effects, with little evidence for dominance gene effects and with no epistasis present. Genetic control of rooting percentage was weak with narrow-sense and broad-sense heritabilities of 0.15 and 0.13, respectively. Selection based on either family means or clone means represented a better strategy than mass selection, as evidenced by narrow-sense and broad-sense heritabilities of 0.46 and 0.40, respectively. Predicted genetic gain in rooting percentage was estimated using two population improvement alternatives. Selection of the best 10% of the clones would increase overall rooting percentage to 53.6% in the current generation, an increase of 11.3%; whereas selection of the best individual within the best 24 of the 54 families and intermating the select trees would increase rooting percentage of the next generation to 54.1 %, an increase of 11.8%.

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