Genetic variation in juvenile growth of tamarack (Larixlaricina) in northwestern Ontario

1993 ◽  
Vol 23 (9) ◽  
pp. 1852-1862 ◽  
Author(s):  
Robert E. Farmer Jr. ◽  
Gwenoth O'Reilly ◽  
Deng Shaotang
Keyword(s):  
Genetic Variation ◽  
Common Garden ◽  
Shoot Elongation ◽  
Allozyme Variation ◽  
Broad Sense ◽  
Population Variation ◽  
Broad Sense Heritability ◽  
Northwestern Ontario ◽  
Test Population ◽  
N 93

Nested designs incorporating provenances and families and clones within provenances were used in two common garden tests near Thunder Bay, Ont. (48°N, 84°W) to evaluate genetic variation in growth and sylleptic branching among and within populations of tamarack (Larixlaricina (Du Roi) K. Koch) from 46°N, 80°W to 53°N, 93°W. At 7 and 8 years there was a north-south trend of increasing height among provenances. Genetic variation in height was related to both rate and duration of shoot elongation, but latitudinal variation in shoot growth mainly resulted from differences in late-season elongation. There was substantial genetic variance in height within populations, and broad-sense heritability based on pooled variances was 0.23 for one test population at 8 years and 0.11 for the second at 7 years. The more vigorous southern provenances had a greater potential for sylleptic branching in the test area than northern sources, and wide within-population variation in syllepsis was under stronger genetic control than growth (broad-sense heritability = 0.47 in year 6). Patterns of genetic variation observed in the study were not congruent with patterns of morphological and allozyme variation previously reported for the sampled populations.

scholarly journals Genetic variation and correlation of agronomic traits in meadow bromegrass (Bromus riparius Rehm) clones

2004 ◽  
Vol 34 (2) ◽  
pp. 505-510 ◽  
Author(s):  
Marcelo Renato Alves de Araújo ◽  
Bruce Coulman
Keyword(s):  
Genetic Variation ◽  
Crude Protein ◽  
Genetic Correlations ◽  
Neutral Detergent Fiber ◽  
Broad Sense ◽  
Grass Species ◽  
Broad Sense Heritability ◽  
Bromus Riparius ◽  
Heritability Estimates ◽  
Meadow Bromegrass

Meadow bromegrass (Bromus riparius Rehm.) is a recently introduced pasture grass in western Canada. Its leafy production and rapid regrowth have made it a major grass species for pasturing beef animals in this region. As relatively little breeding work has been done on this species, there is little information on its breeding behaviour. The main objective of this study was to estimate total genetic variability, broad-sense heritability, phenotypic and genetic correlations. Forty-four meadow bromegrass clones were evaluated for agronomic characters. Genetic variation for dry matter yield, seed yield, fertility index, harvest index, plant height, plant spread, crude protein, neutral detergent fiber and acid detergent fiber, was significant. Broad-sense heritability estimates exceeded 50% for all characters. Heritability estimates were at least 3.5 times greater than their standard errors. Phenotypic and genetic correlation between all possible characters were measured. There was general agreement in both sign and magnitude between genetic and phenotypic correlations. Correlations between the different characters demonstrated that it is possible to simultaneously improve seed and forage yield. Based on the results, it appears that the development of higher yielding cultivars with higher crude protein, and lower acid and neutral detergent fibers concentration should be possible.

Heritability and C effects in a 3-year-old balsam poplar clonal test

1988 ◽  
Vol 18 (8) ◽  
pp. 1059-1062 ◽  
Author(s):  
Robert E. Farmer Jr. ◽  
Karen Garlick ◽  
Steven R. Watson
Keyword(s):  
Field Test ◽  
Shoot Elongation ◽  
Broad Sense ◽  
Broad Sense Heritability ◽  
Height Variation ◽  
Balsam Poplar ◽  
Clonal Test

A 20-clone population of Populusbalsamifera L. was grown for 3 years in a field test which allowed evaluation of variance due to clones and to primary ramets within clones, the source of cuttings. Primary ramets did not influence rate of summer shoot elongation, which had a broad-sense heritability of 0.24 and 0.16 in the 2nd and 3rd years, respectively. By the end of the 2nd year, height variation associated with primary ramets (i.e., C effects) was nonsignificant, and broad-sense heritability for height was about 0.50.

scholarly journals Genetic resistance of Eucalyptus globulus to autumn gum moth defoliation and the role of cuticular waxes

2002 ◽  
Vol 32 (11) ◽  
pp. 1961-1969 ◽  
Author(s):  
T H Jones ◽  
B M Potts ◽  
R E Vaillancourt ◽  
N W Davies
Keyword(s):  
Genetic Variation ◽  
Eucalyptus Globulus ◽  
Field Trial ◽  
Genetic Resistance ◽  
Cuticular Wax ◽  
Wax Esters ◽  
Broad Sense ◽  
Broad Sense Heritability ◽  
Cuticular Waxes

This study investigated the association between resistance of Eucalyptus globulus Labill. to autumn gum moth (Mnesempala privata Guenée) defoliation and cuticular wax compounds. In a field trial consisting of clonally replicated F2 families of E. globulus, situated in Tasmania, Australia, significant genetic variation in resistance was detected in two of three F2 families. The broad-sense heritability for defoliation within families ranged from 0.24 to 0.33. The 15 most resistant and the 15 most susceptible genotypes within each variable family were compared for their relative levels of 26 cuticular wax compounds. While no significant correlation between resistance and total wax yield estimates was found, significant differences were detected between resistant and susceptible classes in the relative quantities of several aliphatic phenylethyl and benzyl wax esters within both families. This association does not appear to be a response induced by defoliation. The broad-sense heritabilities of the variation in these compounds were high (0.82–0.94). Our findings suggest that these wax compounds are a mechanism of genetic resistance to autumn gum moth in E. globulus.

scholarly journals Variance Components and Estimates of Broad-sense Heritability of Nut and Kernel Traits in Hazelnut

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 494D-494
Author(s):  
Qiang Yao ◽  
Shawn A. Mehlenbacher
Keyword(s):  
Genetic Variation ◽  
Phenotypic Variation ◽  
Variance Components ◽  
Genetic Basis ◽  
Corylus Avellana ◽  
Broad Sense ◽  
Broad Sense Heritability ◽  
Narrow Sense ◽  
High Heritability ◽  
Kernel Traits

Seventy-seven trees representing 41 hazelnut (Corylus avellana L.) genotypes were to evaluate variance components and broad-sense heritability for 10 nut and kernel traits from 1994 to 1996. All effects in the models were assumed to be random. All traits had extremely high heritability. This indicated that nearly all of the phenotypic variation had a genetic basis. Knowledge of variance components may help us efficiently allocate resources. Broad-sense heritability estimates were larger than those in narrow sense, suggesting the presence of nonadditive genetic variation in the population.

A model of genetic variation for Pinus ponderosa in the Inland Northwest (U.S.A.): applications in gene resource management

1991 ◽  
Vol 21 (10) ◽  
pp. 1491-1500 ◽  
Author(s):  
G. E. Rehfeldt
Keyword(s):  
Genetic Variation ◽  
Pinus Ponderosa ◽  
Regression Models ◽  
Common Garden ◽  
Shoot Elongation ◽  
The United States ◽  
Independent Data ◽  
Gene Conservation ◽  
Seed Transfer ◽  
Inland Northwest

Models were developed to describe genetic variation among 201 seedling populations ofPinusponderosa var. ponderosa in the Inland Northwest of the United States. Common-garden studies provided three variables that reflected growth and development in field environments and three principal components of six variables that reflected patterns of shoot elongation. Regression models were developed for describing genetic variation across the landscape. Using functions of latitude, longitude, and elevation as descriptors, these models produced values of R2 that were as large as 0.66, while averaging 0.39. The models described genetic variation as occurring along relatively steep elevational clines and gentle geographic (i.e., latitudinal and longitudinal) clines. An exercise at validating the models with independent data supported their veracity. Predictions made by the models are applied to limiting seed transfer, designing breeding zones, planning gene conservation programs, interpreting phenotypic variation, and predicting the effects of environmental change on the adaptedness of populations.

scholarly journals POPULATION GENETICS OF ALLOZYME VARIATION IN NEUROSPORA INTERMEDIA

Genetics ◽  
1975 ◽  
Vol 80 (4) ◽  
pp. 785-805
Author(s):  
P T Spieth
Keyword(s):  
Genetic Variation ◽  
Vegetative Reproduction ◽  
Vascular Plant ◽  
Natural Populations ◽  
Allozyme Variation ◽  
Regular Feature ◽  
Local Populations ◽  
Neurospora Intermedia ◽  
Pattern Of Variation ◽  
High Level

ABSTRACT Electrophoretically detectable variation in the fungus Neurospora intermedia has been surveyed among isolates from natural populations in Malaya, Papua, Australia and Florida. The principal result is a pattern of genetic variation within and between populations that is qualitatively no different than the well documented patterns for Drosophila and humans. In particular, there is a high level of genetic variation, the majority of which occurs at the level of local populations. Evidence is presented which argues that N. intermedia has a population structure analogous to that of an annual vascular plant with a high level of vegetative reproduction. Sexual reproduction appears to be a regular feature in the biology of the species. Substantial heterokaryon function seems unlikely in natural populations of N. intermedia. Theoretical considerations concerning the mechanisms underlying the observed pattern of variation most likely should be consistent with haploid selection theory. The implications of this constraint upon the theory are discussed in detail, leading to the presentation of a model based upon the concept of environmental heterogeneity. The essence of the model, which is equally applicable to haploid and diploid situations, is a shifting distribution of multiple adaptive niches among local populations such that a given population has a small net selective pressure in favor of one allele or another, depending upon its particular distribution of niches. Gene flow among neighboring populations with differing net selective pressures is postulated as the principal factor underlying intrapopulational allozyme variation.

High Heritability of Glycyrrhizic Acid, Glabridin, Liquiritin and Liquiritigenin in Licorice (Glycyrrhiza Glabra L.) Populations of Iran

2021 ◽  
Author(s):  
Ghasem Eghlima ◽  
Mohsen Sanikhani ◽  
Azizollah Kheiry ◽  
Javad Hadian
Keyword(s):  
Coefficient Of Variation ◽  
Morphological Traits ◽  
Glycyrrhizic Acid ◽  
Correlation Coefficients ◽  
Glycyrrhiza Glabra ◽  
Broad Sense ◽  
Phenotypic Correlation ◽  
Broad Sense Heritability ◽  
Narrow Sense Heritability ◽  
Perennial Plant

Abstract Glycyrrhiza glabra L. is an herbaceous, perennial plant with high distribution in Iran. Genetic variability, heritability and correlation among characters in 22 populations of G. glabra L. were studied. The genetic parameters among the traits including phenotypic variances, genotypic variances, genotype by environment variances, broad-sense heritability and genotypic and phenotypic correlation coefficients were studied. Variance components analysis showed that the extent of phenotypic coefficient of variation (PCV) was fairly higher for all the examined traits compared with genotypic coefficient of variation (GCV). Glabridin (GLA) exhibited high GCV and PCV (156.07% and 156.68%, respectively). The broad sense heritability varied from 38.92–99.79% and narrow sense heritability ranged from 9.70 % to 24.94%. Heritability of GLA, glycyrrhizic acid (GLY), liquiritin (LI), liquiritigenin (LIQ), rutin (RU) and rosmarinic acid (RA) were very high, exhibiting more than 97% heritability. Therefore, these critical characteristics can efficiently be selected and inherited in breeding programs. In most traits, the genotypic correlations showed the same direction as the phenotypic correlations. The contents of GLA and LIQ showed a positive correlation with majority of morphological traits. Therefore, selecting individual plants having desired morphological traits can be correlated with high contents of bioactive compounds in the harvested root.

scholarly journals Evidence of between-population differences in natural selection on extra-floral nectaries of the shrub Anemopaegma album (Bignoniaceae)

Botany ◽  
2016 ◽  
Vol 94 (3) ◽  
pp. 201-213
Author(s):  
Anselmo Nogueira ◽  
Pedro J. Rey ◽  
Julio M. Alcántara ◽  
Lúcia G. Lohmann
Keyword(s):  
Genetic Variation ◽  
Natural Selection ◽  
Evolutionary Ecology ◽  
Common Garden ◽  
Phenotypic Selection ◽  
Population Differences ◽  
Wild Populations ◽  
Neotropical Savanna ◽  
Foliar Damage ◽  
Floral Nectaries

Extra-floral nectaries (EFNs) are thought to represent protective adaptations against herbivory, but studies on the evolutionary ecology of EFNs have seldom been conducted. Here we investigate the patterns of natural selection and genetic variation in EFN traits in two wild populations of Anemopaegma album Mart. ex DC. (Bignoniaceae) that have been previously described as contrasting EFN – ant adapted localities in the Neotropical savanna (Cristália and Grão Mogol). In each population, four EFN descriptors, foliar damage, and reproductive success variables were measured per plant (100–120 plants per population). To estimate the heritability of EFN traits, we crossed reproductive plants in the field, and grew offspring plants in a common garden. The results showed that ant assemblages differed between populations, as did the range of foliar herbivory. Genetic variation and positive phenotypic selection in EFN abundance were only detected in the Cristália population, in which plants with more EFNs were more likely to reproduce. An evaluation of putative causal links conducted by path analysis corroborated the existence of phenotypic selection on EFNs, which was mediated by the herbivory process in the Cristália population. While EFNs could be currently under selection in Cristália, it is possible that past selection may have driven EFN traits to become locally adapted to the local ant assemblage in the Grão Mogol population.

Clonal testing efficiency: the trade-offs between clones tested and ramets per clone

1986 ◽  
Vol 16 (5) ◽  
pp. 925-930 ◽  
Author(s):  
J. H. Russell ◽  
W. J. Libby
Keyword(s):  
Clonal Selection ◽  
Simulation Models ◽  
Radiata Pine ◽  
Fixed Number ◽  
Broad Sense ◽  
Optimum Level ◽  
Broad Sense Heritability ◽  
Selection Intensity ◽  
Trade Offs ◽  
Clonal Testing

Three contrasting simulation models were developed to investigate testing efficiencies in a clonal selection program. The variables investigated were number of total plants tested, number of candidate clones tested, number of ramets per clone, number of clones selected, selection intensity, and broad-sense heritability. The model deemed appropriate to most clonal forestry situations selected a fixed number of clones in an experiment with the total number of plants in the test held constant. In this model, as the number of ramets per clone was varied, the number of candidate clones tested and the selection intensity necessarily also varied. This model indicates that cloning individuals for testing is useful when selection is based on a characteristic or index with broad-sense heritability less than about 0.6. At the lower heritabilities, two to six ramets per clone per site usually produces the optimum level of cloning, the exact number depending upon the selection intensity and heritability. Predictions generated by this fixed number of selected clones model were compared with average phenotypic values of selections using different subsamples of data for 8-year height and for 8-year diameter in a radiata pine (Pinusradiata D. Don) clonal experiment. Agreement between predictions and average phenotypic values in both these two comparisons was close.

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