Trends in variances and heritabilities with stand development of tropical pines

1996 ◽  
Vol 26 (8) ◽  
pp. 1473-1480 ◽  
Author(s):  
J. Vásquez ◽  
W.S. Dvorak
Keyword(s):  
Phenotypic Trait ◽  
Phenotypic Variance ◽  
Narrow Sense ◽  
Ontogenetic Changes ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Genetic Variances ◽  
Rate Of Increase ◽  
The Individual ◽  
Over Time

Phenotypic and additive genetic variances as well as narrow-sense heritability for cumulative height were determined from assessments of tropical pine (Pinuscaribaea Morelet, Pinuschiapensis (Mart.) Andresen, and Pinustecunumanii (Schw.) Eguiluz et Perry) trials established in South America and South Africa by the Central America and Mexico Coniferous Resources (CAMCORE) Cooperative. Cumulative stem height was analyzed from 1-, 3-, 5-, and 8-year data collected on open-pollinated families to determine additive genetic and phenotypic variances. Variances based on arithmetic as well as log-transformed values are presented. Phenotypic and genetic variances of log-transformed values decreased over time, probably reflecting the onset of intergenotypic competition. Absolute variances increased over time as the trials became older, but the rate of increase for phenotypic variance was greater than that for additive variance. Individual narrow-sense heritabiiities changed over time but without showing any definite trend by species. It appeared that variance trends reflected the varying ontogenetic changes during the development of the stands, which could be indicated by size of the trees rather than by their age. Breeding strategies in tropical pines should consider the increasing intensity of environmental effects as a stand matures, since they cause a decline of genetic variances at a higher rate than phenotypic variances. Furthermore, it is hypothesized that a phenotypic trait at a given ontogenetic stage of the individual is under temporal control of a set of genes that changes as the temporal environmental conditions change.

scholarly journals DYNAMICS OF HERITABILITY IN DIFFERENT CHARACTERS OF LETTUCE

2021 ◽  
Vol 34 (3) ◽  
pp. 514-526
Author(s):  
ALISSON HENRIQUE GAMA DE OLIVEIRA ◽  
GABRIEL MASCARENHAS MACIEL ◽  
ANA CAROLINA SILVA SIQUIEROLI ◽  
JOSÉ MAGNO QUEIROZ LUZ ◽  
ERNANI CLARETE DA SILVA
Keyword(s):  
Chlorophyll Content ◽  
Gene Action ◽  
Gene Interactions ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Dominant Type ◽  
Partial Dominance ◽  
Number Of Genes ◽  
Number Of Leaves

ABSTRACT The lack of knowledge of the genetic parameters and the type of gene action results in difficulties to obtain varieties that combine agronomic and functional characteristics. The objective of this study was to determine the type of gene action associated with the contents of chlorophyll and agronomic characteristics in lettuce populations. The research was conducted at the Experimental Station of Vegetables, Monte Carmelo, Brazil. To perform the crosses and obtain the generations P1, P2, F1, F2, Bc1 and Bc2 the genotypes UFU-Albina#2, UFU-Albina#3, UFU-Lisa124#2#1, UFU-Crespa199#1#1 and UFU-Lisa217#5#2 were used as parents. The generations were evaluated for three characteristics: number of leaves, plant diameter and chlorophyll content. The parameters: genetic, phenotypic, environmental and additive variance, the dominance in F2, heritability in the broad and narrow-sense, the average degree of dominance based on averages, number of genes, the measure of the dominance deviations, additive effects and all interactions of ‘additive x additive’, ‘additive x dominant’ and ‘dominant x dominant’ type, were evaluated. Chlorophyll content was the most influenced by the environment. Plant diameter had the highest narrow-sense heritability for the cross UFU-Lisa-124#2#1 x UFU-Albina#3 (82.1%). The number of genes for the number of leaves varied from inconclusive to a minimum of 9 genes. The gene interactions for number of leaves were of overdominance type, while for plant diameter and for chlorophyll content the gene interactions were of partial dominance. The characteristics are suggested as being of polygenic or oligogenic nature.

scholarly journals GENERATION MEAN ANALYSIS USING GENERATION VARIANCE IN DURUM WHEAT TRAITS (Triticum durum L.)

2020 ◽  
Vol 51 (5) ◽  
pp. 1308-1313
Author(s):  
H. S. Ali Askander
Keyword(s):  
Durum Wheat ◽  
Plant Height ◽  
Mean Value ◽  
Narrow Sense ◽  
Generation Mean Analysis ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Gene Effects ◽  
Gene Effect ◽  
Engineering Sciences

The present investigation was conducted to estimate the gene action effects in some traits of durum wheat by using crosses two generation of wheat (Albit-9 X omgenil-3) through generation mean analysis during growing season 2016-2017, at Field Crops Department, Collage of Agricultural Engineering Sciences, University of Duhok. The analysis of variance showed significant differences between generations mean for studied traits except spike length which did not significant. The mean value of F1 generation was higher than the respect parents (P1 and P2) F2, Bc1 and Bc2 for most of studied traits in wheat crosses. The results of gene effect shown that the dominance gene effects were significant and positive with all studied traits, whereas additive gene effect did not significant for all traits except plant height and number of grain per spike, also The results exhibited that the dominance and additive X additive variance was positive for all traits this mean complementary gene effect controlling these traits, regarding of broad and narrow sense heritability. The results indicate that broad sense value was more than the narrow sense heritability. Heterosis in F1 cross over mid parents was recorded a positive value (9.672, 8.112) for plant height and grain yield per plant, while inbreeding depression was measured as reduction in performance of F2 generation a positive results were obtained for all traits.   

scholarly journals Estimation of Genetic Parameter for Quantitative Characters of Pepper (Capsicum annuum L.)

2014 ◽  
Vol 1 (1) ◽  
pp. 4-8 ◽  
Author(s):  
Muhamad Syukur ◽  
Syaidatul Rosidah
Keyword(s):  
Plant Height ◽  
Genetic Parameters ◽  
Genetic Parameter ◽  
Stem Diameter ◽  
Broad Sense Heritability ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Fruit Length ◽  
Quantitative Characters

The research was conducted at Leuwikopo Experimental Field and Plant Breeding Laboratory of IPB, Dramaga, Bogor, West Java, Indonesia from October 2012 to April 2013. Crossing population between C15 and C2 genotype were used to study genetic parameters for quantitative characters in pepper. All the characters were not controlled by maternal effect, except fruit length. Broad-sense heritability were high for plant height, stem diameter, dichotomous height, days to flower, days to harvest; and medium for fruit length and diameter. Narrow-sense heritability was high for stem diameter, dichotomous height, days for flowering; medium for plant height, days to harvest; and low for fruit length and diameter. The ratio of additive variance was high for all the characters, except for fruit length and fruit diameter.Keywords: heritability, heterosis, heterobeltiosis, additive variance, dominant variance

scholarly journals Inheritance of Resistance to Colletotrichum Species in Strawberry

1991 ◽  
Vol 116 (4) ◽  
pp. 724-727 ◽  
Author(s):  
Creighton L. Gupton ◽  
Barbara J. Smith
Keyword(s):  
Recurrent Selection ◽  
Major Gene ◽  
Broad Sense ◽  
Inheritance Of Resistance ◽  
Broad Sense Heritability ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Genetic Variances ◽  
Heritability Estimates ◽  
Selection Of

Experiments were conducted to estimate the relative importance of additive and dominance genetic variances and non-allelic interactions in the inheritance of resistance to Colletotrichum spp. in strawberry (Fragaria × ananassa Duch.). Progeny of 40 parents crossed in a Comstock and Robinson Design II Mating scheme were inoculated with three isolates of C. fragariae and one isolate of C. acutatum. Disease development on each plant was rated visually. Variance components were estimated and converted to genetic variances. Estimates of were six to 10 times higher than those for Within-family variance not accounted for by equaled 35% and 38% of the total genetic variance in females and males, respectively, indicating probable epistatic effects. The frequency distribution of disease severity ratings was bimodal in both experiments, suggesting major gene action. Narrow-sense heritability estimates were 0.37 and 0.26, and broad-sense heritability estimates were 0.87 and 0.85 for females and males, respectively. Narrow-sense heritability estimates are probably sufficient to produce gains from recurrent selection. Gains from selection of clonal value should be possible because of the high broad sense heritability estimates. It appears feasible to establish a broad genetic-based population resistant to Colletotrichum spp. from which selections could be evaluated per se and/or recombined to produce improved populations.

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

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.

Changes in the pattern of genetic variability over time in American sycamore and the implication for early selection

1992 ◽  
Vol 22 (5) ◽  
pp. 713-717 ◽  
Author(s):  
T.A. Greene ◽  
W.J. Lowe
Keyword(s):  
Volume Growth ◽  
Stem Canker ◽  
Early Selection ◽  
Phenotypic Variance ◽  
Additive Variance ◽  
Individual Tree ◽  
Genetic Prediction ◽  
Family Effects ◽  
Error Terms ◽  
Over Time

Height, volume, and stem canker symptom data were collected at ages 3, 5, 7, 10, 13, and 15 years in three genetic tests of American sycamore (Platanusoccidentalis L.) planted in Texas and Louisiana. Five provenances from Texas, Arkansas, and Louisiana were represented in the tests. Data were subjected to analysis of variance; heritabilities, coefficients of genetic prediction, and variance components were calculated. Provenance had no significant effect on height and volume; however, northern provenances tended to be more susceptible to stem canker. Significant family effects occurred for height and volume at all ages, and family heritabilities were moderate to high for all traits. Coefficients of genetic prediction between age 3 height and age 15 volume and canker rating were large and positive, suggesting that early selection to improve 15-year volume and canker resistance in sycamore would be possible. Over the course of this study, the additive variance for height and volume growth gradually increased. The variance attributed to the plantation x family interaction was generally small and nonsignificant. Changes in height and volume individual tree heritabilities over time were due to changes in the magnitude of the between-plot and within-plot error terms and their impact on phenotypic variance. This appeared to be caused by differential timing and severity of stem canker infection in the tests.

scholarly journals Genetic variance for body size in a natural population of Drosophila buzzatii.

Genetics ◽  
1991 ◽  
Vol 128 (4) ◽  
pp. 739-750
Author(s):  
A Ruiz ◽  
M Santos ◽  
A Barbadilla ◽  
J E Quezada-Díaz ◽  
E Hasson ◽  
...  
Keyword(s):  
Genetic Variance ◽  
Genetic Model ◽  
Phenotypic Variance ◽  
Total Phenotypic Variance ◽  
Fourth Chromosome ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Thorax Length ◽  
Drosophila Buzzatii ◽  
F2 Generation

Abstract Previous work has shown thorax length to be under directional selection in the Drosophila buzzatii population of Carboneras. In order to predict the genetic consequences of natural selection, genetic variation for this trait was investigated in two ways. First, narrow sense heritability was estimated in the laboratory F2 generation of a sample of wild flies by means of the offspring-parent regression. A relatively high value, 0.59, was obtained. Because the phenotypic variance of wild flies was 7-9 times that of the flies raised in the laboratory, "natural" heritability may be estimated as one-seventh to one-ninth that value. Second, the contribution of the second and fourth chromosomes, which are polymorphic for paracentric inversions, to the genetic variance of thorax length was estimated in the field and in the laboratory. This was done with the assistance of a simple genetic model which shows that the variance among chromosome arrangements and the variance among karyotypes provide minimum estimates of the chromosome's contribution to the additive and genetic variances of the trait, respectively. In males raised under optimal conditions in the laboratory, the variance among second-chromosome karyotypes accounted for 11.43% of the total phenotypic variance and most of this variance was additive; by contrast, the contribution of the fourth chromosome was nonsignificant. The variance among second-chromosome karyotypes accounted for 1.56-1.78% of the total phenotypic variance in wild males and was nonsignificant in wild females. The variance among fourth chromosome karyotypes accounted for 0.14-3.48% of the total phenotypic variance in wild flies. At both chromosomes, the proportion of additive variance was higher in mating flies than in nonmating flies.

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.

GENETIC VARIANCES IN AN EIGHT PARENT HALF DIALLEL OF OATS

1976 ◽  
Vol 18 (3) ◽  
pp. 419-427 ◽  
Author(s):  
D. R. Sampson ◽  
I. Tarumoto
Keyword(s):  
Grain Yield ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Heading Date ◽  
Phenotypic Variance ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Additive Component ◽  
Tests Of Fit ◽  
Half Diallel

Twenty-eight progenies with their eight parent cultivars of Avena saliva L. (2n = 6x = 42) were grown in F1, F2 and F3 in separate years; the F1 as spaced plants, the F2 and F3 as dense seeded populations. Additive genetic variance constituted most of the phenotypic variance of eight traits (heading date, plant height, stem diameter, grain yield and four components of yield) according to a Griffing Method 4, Model II analysis. Similarly, additive × year interactions were more important than nonadditive × year interactions. A Hayman-Jinks analysis of the same material but with the parents included showed that the additive component was 2 to 16 times larger than the dominance components in the F1 However in the F2 and F3 the dominance components became larger than the additive components for most traits instead of declining in importance as expected. Further, tests of fit to the hypotheses underlying the Hayman-Jinks analysis were negative in 8 of 24 cases. It is postulated that these discrepancies result from epistatic variance which caused an upward bias in the dominance estimates. The calculation and uses of two estimates of narrow-sense heritability are discussed.

ADDITIVE AND NONADDITIVE GENETIC VARIANCES AND GENOTYPIC CORRELATIONS FOR YIELD AND OTHER TRAITS IN OATS

1971 ◽  
Vol 13 (4) ◽  
pp. 864-872 ◽  
Author(s):  
D. R. Sampson
Keyword(s):  
Seed Weight ◽  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Heading Date ◽  
Stem Diameter ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Plot Yield ◽  
Panicle Number

The oat cultivate 'Dorval', 'Kelsey', 'Stormont', 'Orbit', 'Goodfield', 'Tyler' and 'Egdolon' and two numbered lines were crossed in a 3 × 6 factorial design. F1's, F2's and bullied F2 progenies were grown in successive years at seeding rates of 2.7, 9.5 and at the commercial rare of 76 Kg/ha, respectively; the F1's in irrigated cages, the F2's and F3's in nonirrigated fields. Additive genetic variance was the most important component of the phenotypic variances among progenies. Major differences occurred between the F1's and F2's, but the F2's and F3's agreed closely. The percentages of additive variance (narrow sense heritability) for the joint F2, F3 analyses were: height (91); heading date (87); seed weight (74); yield per panicle (71); seeds per panicle (63); panicle number (58); stem diameter (55); plot yield (52). Important nonadditive variance was present in the F2, F3 data for plot yield (17%), stem diameter (15%) and seed weight (12%). All traits were positively correlated with each other in the F1's. Correlations were weaker in the F2 and F3 and reversed for panicle number. Seed weight showed the least correlation with other traits. These results are discussed from the practical viewpoint of combining strong straw with high grain yield. The usefulness of selecting for seed weight and panicle yield to improve plot yield is underlined.

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