Genetic variation and productivity of Populustrichocarpa and its hybrids. III. Structure and pattern of variation in a 3-year field test

1989 ◽  
Vol 19 (3) ◽  
pp. 372-377 ◽  
Author(s):  
D. L. Rogers ◽  
R. F. Stettler ◽  
P. E. Heilmann
Keyword(s):  
Block Design ◽  
Natural Populations ◽  
Large Degree ◽  
Population Variation ◽  
Black Cottonwood ◽  
Narrow Sense Heritability ◽  
Ongoing Work ◽  
Pattern Of Variation ◽  
Significant Block ◽  
River Valleys

Growth and morphology of 308 black cottonwood (Populustrichocarpa Torr & Gray) clones were studied at one plantation site in northwestern Washington. The material was derived from both open-pollinated seed and branch cuttings from 10 natural populations in major river valleys west of the Cascade Range, between central Oregon (latitude 44°44′) and southern British Columbia (latitude 49°05′). Most of the clones (258) were derived from open-pollinated seedlings, with approximately six from each of two to five selected parents per population. Fifty of the clones were ramets from five field-selected ortets per population. Each clone was represented by two ramets in each of two blocks in a randomized complete block design. Three-year height and diameter growth displayed the largest amount of variation at the clonal level, followed by lesser amounts at the family and population levels. A significant block × clone interaction, combined with some responses contrasting with earlier studies on a different site, suggests that the interaction of genotype with environment is important for this species. Weak clinal trends were observed, despite a large degree of within-population variation. Narrow-sense heritability estimates and their standard errors were 0.10 ± 0.08 and 0.13 ± 0.09 for 3rd-year height and diameter, respectively. Significant trait correlations were obtained between volume and branch characteristics. The implications of these results and their relationship to other ongoing work in black cottonwood are discussed.

Cyanogenic polymorphism as an indicator of genetic diversity in the rarespecies Eucalyptus yarraensis (Myrtaceae)

2002 ◽  
Vol 29 (12) ◽  
pp. 1445 ◽  
Author(s):  
Jason Q. D. Goodger ◽  
Ian E. Woodrow
Keyword(s):  
Genetic Diversity ◽  
Effective Means ◽  
Natural Populations ◽  
Population Variation ◽  
Conservation Strategy ◽  
Narrow Sense Heritability ◽  
Specialist Herbivores ◽  
Cyanogenic Plants ◽  
Physical And Chemical ◽  
First Time

The rare Australian tree Eucalyptus yarraensis Maiden & Cambage is cyanogenic, a quantitative trait potentially indicative of genetic diversity. Cyanogenic plants are capable of releasing cyanide from endogenous cyanide-containing compounds. Cyanide is toxic or deterrent to generalist or non-adapted specialist herbivores. Consequently, cyanogenic plants are afforded an effective means of chemical defense. In this paper we characterize quantitative variation in cyanogenic capability, known as cyanogenic polymorphism, in E. yarraensis for the first time. We show that the cyanogenic glucoside prunasin (R-mandelonitrile-β-D-glucoside) is the only cyanogenic compound in E. yarraensis foliage. We also show that two natural populations of E. yarraensis display extensive intra- and inter-population variation in foliar prunasin concentration. The high prunasin concentrations reported in this paper represent the highest yet recorded for mature eucalypt leaves. The cyanogenic variation could not be attributed to measured physical and chemical parameters, supporting the hypothesis that the variation is genetically based. A preliminary progeny trial also supports this hypothesis, with narrow sense heritability estimated at 1.17 from three half-sibling families. The variation in cyanogenic capability may be a useful tool in the development of a conservation strategy for the species.

scholarly journals Genetic variation in phenology and growth among and within Norway spruce populations from two altitudinal transects in Mid-Norway

Silva Fennica ◽  
2019 ◽  
Vol 53 (1) ◽  
Author(s):  
Tore Skrøppa ◽  
Arne Steffenrem
Keyword(s):  
High Altitude ◽  
Norway Spruce ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Height Growth ◽  
Population Variation ◽  
Clinal Variation ◽  
Short Term ◽  
Narrow Sense Heritability

Progenies from open pollinated cones collected in natural populations of Norway spruce ( (L. Karst.)) distributed along two altitudinal transects in Mid-Norway were tested in the nursery, in short term tests and in long-term field trials. The populations showed clinal variation related to the mean annual temperatures of the populations, with the earliest bud flush and cessation of shoot elongation and lowest height at age nine years for the high altitude populations. Within population variation was considerable as the narrow sense heritability for these traits was 0.67, 0.31 and 0.09 in one transect and 0.55, 0.18 and 0.14 in the other transect, respectively. Lammas shoots occurred in the short term trials with large variation in frequency between years. There was significant family variation for this trait, but also interactions between populations and year. The variance within populations was considerably larger in the populations from low altitude compared to the high-altitude populations. Significant genetic correlations between height and phenology traits and damage scores indicate that families flushing early and ceasing growth late were taller. Taller families also had higher frequencies of damages. Selection of the top 20% families for height growth in short term tests at age nine years gave a simulated gain of 11% increased height growth at age 18 years in long term trials at altitudes similar to those of origin of the populations. The gain was negative when high altitude populations were selected based on testing in the lowland.Picea abies

Genetic variation and productivity of Populustrichocarpa and its hybrids. I. Morphology and phenology of 50 native clones

1985 ◽  
Vol 15 (2) ◽  
pp. 376-383 ◽  
Author(s):  
J. C. Weber ◽  
R. F. Stettler ◽  
P. E. Heilman
Keyword(s):  
Clonal Selection ◽  
Natural Populations ◽  
Principal Component ◽  
Black Cottonwood ◽  
Population Means ◽  
Major River ◽  
Continue Growth ◽  
Genetic Cline ◽  
Source Populations ◽  
River Valleys

Morphological and phenological variation among five black cottonwood (Populustrichocarpa Torr. & Gray) clones from each of 10 natural populations were studied at one plantation site in western Washington. Source populations are located in major river valleys, west of the Cascade Mountains, between central Oregon (latitude 44°44′ N) and southern British Columbia (latitude 49°05′ N). Populations and individual clones were selected for superior form and growth rate. Tested at a spacing of 1.2 × 1.2 m, the 50 clones displayed a large range of variation in 15 leaf, branch, and phenology characters studied. Clones and populations differed significantly in 14 and 10 characters, respectively. Population means for seven characters and a character association (principal component) varied clinally with source latitude, longitude, and (or) elevation. The most consistent genetic cline follows a geographic gradient from southwest to northeast: southwestern clones develop smaller leaves on more erect branches, and continue growth later in the fall. Variation patterns seem to reflect regional climatic gradients, annual disturbance in riparian environments, and the life history characteristics of the species. The results point to the great potential of clonal selection for black cottonwood improvement.

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.

scholarly journals Generation Mean Analysis in Cowpea [Vigna unguiculata (L.) Walp.] under Flower Thrips infestation

2018 ◽  
Vol 10 (4) ◽  
pp. 86 ◽  
Author(s):  
Gonné Sobda ◽  
Fonji Maureen Atemkeng ◽  
Ousmane Boukar ◽  
Chistian Fatokun ◽  
Pangirayi Bernard Tongoona ◽  
...  
Keyword(s):  
Block Design ◽  
Generation Mean Analysis ◽  
Flower Number ◽  
Narrow Sense Heritability ◽  
Gene Effects ◽  
Flower Thrips ◽  
Randomized Block Design ◽  
Cowpea Resistance ◽  
Predominant Type ◽  
Screen House

Two sets of six generations (P1, P2, F1, F2, BC1P1, BC1P2) of cowpea were developed from crosses of contrasting inbred lines VYA (susceptible) × SANZI (resistant) and LORI (susceptible) × SANZI (resistant). The aim of this study was to determine the inheritance and elucidate the genetic control of cowpea resistance to thrips. The first set (VYA × SANZI) was evaluated under natural thrips infestation in the field in a completely randomized block design with three replications. The second set (LORI × SANZI) was screened using artificial thrips infestation in the screen house. In each trial, data were recorded on 150 individual plants. These included the score of thrips damages using the scale of one to nine, number of thrips per flower, number of pods per plant, pod weight per plant and grain weight per plant. The generation mean analysis revealed that both additive and non-additive types of gene effects were significant. Dominance × dominance was the most predominant type of gene effects for thrips resistance, suggesting that breeders should delay selection to late generations to allow advancement of as many high-potential recombinants as possible during hybridization. The number of genes that control the expression of number of thrips per flower was three and ranged from three to four, for score of thrips damages. High broad sense and moderate narrow sense heritability were observed ranging from 0.53 to 0.65 and 0.14 to 0.36, respectively for all of the traits measured. 

scholarly journals Genetic Variation for Biomass Yield and Predicted Genetic Gain in Lowland Switchgrass “Kanlow”

Agronomy ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1845
Author(s):  
Santosh Nayak ◽  
Hem Bhandari ◽  
Carl Sams ◽  
Virginia Sykes ◽  
Haileab Hilafu ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Genetic Gain ◽  
Panicum Virgatum ◽  
Biomass Yield ◽  
Block Design ◽  
Perennial Grass ◽  
Warm Season ◽  
Narrow Sense ◽  
Bioenergy Feedstock ◽  
Narrow Sense Heritability

Switchgrass (Panicum virgatum L.) is a warm-season, perennial grass valued as a promising candidate species for bioenergy feedstock production. Biomass yield is the most important trait for any bioenergy feedstock. This study was focused on understanding the genetics underlying biomass yield and feedstock quality traits in a “Kanlow” population. The objectives of this study were to (i) assess genetic variation (ii) estimate the narrow sense heritability, and (iii) predict genetic gain per cycle of selection for biomass yield and the components of lignocelluloses. Fifty-four Kanlow half-sib (KHS) families along with Kanlow check were planted in a randomized complete block design with three replications at two locations in Tennessee: Knoxville and Crossville. The data were recorded for two consecutive years: 2013 and 2014. The result showed a significant genetic variation for biomass yield (p < 0.05), hemicellulose concentration (p < 0.05), and lignin concentration (p < 0.01). The narrow sense heritability estimates for biomass yield was very low (0.10), indicating a possible challenge to improve this trait. A genetic gain of 16.5% is predicted for biomass yield in each cycle of selection by recombining parental clones of 10% of superior progenies.

scholarly journals Components of genetic variability and heritability of grain yield of silage maize

Genetika ◽  
2004 ◽  
Vol 36 (2) ◽  
pp. 121-131 ◽  
Author(s):  
Mile Secanski ◽  
Tomislav Zivanovic ◽  
Goran Todorovic ◽  
Gordana Surlan-Momirovic
Keyword(s):  
Genetic Variability ◽  
Grain Yield ◽  
Genetic Variance ◽  
Block Design ◽  
Inbred Lines ◽  
Narrow Sense Heritability ◽  
Additive Variance ◽  
Silage Maize ◽  
V Genes ◽  
Set Up

The aim of the present study was to evaluate the following parameters for the grain yield of silage maize: variability of inbred lines and their diallel hybrids, superior-parent heterosis and components of genetic variability and heritability on the basis of the diallel set. The two-year four-replicate trial was set up according to the randomized complete-block design at Zemun Polje. It was determined that a genotype, year and their interaction significantly affected variability of this trait. The highest. i.e. the lowest grain yield, on the average for both investigation years. was recorded in the silage maize inbred lines ZPLB402 and ZPLB405. respectively. The analysis of components of genetic variance for grain yield shows that the additive component (D) was lower than the dominant (H1 and H2) genetic variance, while a positive component F and the frequency of dominant (u) and recessive (v) genes for this observed trait point to prevalence of dominant genes over recessive ones. Furthermore. this is confirmed by the ratio of dominant to recessive genes in parental genotypes for grain yield (Kd/Kr> 1) that is greater than unity in both years of investigation. The estimated value of the average degree of dominance (H1/D)1/2 exceeds unity, pointing out to superdominance in inheritance of this trait in both years of investigation. Results of Vr/Vr regression analysis indicate superdominance in inheritance of grain yield. Moreover. a registered presence of non-allelic interaction points out to the need to study effects of epistasis, as it can have a greater significance in certain hybrids. A greater value of dominant than additive variance resulted in high values of broad-sense heritability for grain yield in both investigation years (98.71%, i.e. 97.19% in 1997, i.e. 1998, respectively). and low values of narrow-sense heritability (11.9% in 1997 and 12.2% in 1998).

scholarly journals Evaluating Genetic Parameters and Combining Ability of Starch Viscosity Parameters in Rice Cultivars (Oryza sativa L.)

2019 ◽  
Vol 7 (4) ◽  
pp. 665
Author(s):  
Alireza Haghighi Hasanalideh ◽  
Mehrzad Allahgholipour ◽  
Ezatollah Farshadfar
Keyword(s):  
Combining Ability ◽  
Gene Action ◽  
Oryza Sativa L ◽  
Block Design ◽  
Breeding Methods ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Gene Effects ◽  
Diallel Mating Design ◽  
Additive Gene

This study was undertaken to assess the combining ability of 6 rice varieties, for viscosity parameters and determining gene action controlling Rapid Visco Analyser (RVA) characters. F2 progenies derived from a 6×6 half diallel mating design with their parents were grown in a randomized complete block design with three replications at the research farm of Rice Research Institute of Iran (RRII) in 2015. The diallel analysis by Griffing`s method indicated the involvement of additive and non-additive gene actions controlling RVA traits. For traits PV and FV RI18447-2 and IR50 were the best combiners for increasing and decreasing, respectively. Deylamani and IR50 were the best combiners for increasing and decreasing BV, respectively. Beside, due to more portion of non-additive gene action in controlling trait SV, The Gilaneh × RI18430-46, and Deylamani × RI18430-46 crosses were the best for increasing and decreasing SV, respectively. The high estimates of broad sense heritability and narrow sense heritability for BV and FV, indicated the importance of additive effects in expression of these traits. Therefore, selection base breeding methods will be useful to improve these traits and selection in the early generations could be done to fix the favourable genes. Low estimate of narrow sense heritability for SV revealed that non-additive gene effects play important role in controlling setback viscosity. So, hybrid base breeding methods will be useful to improve this trait.

scholarly journals A quantitative genetic study of starvation resistance at different geographic scales in natural populations of Drosophila melanogaster

2010 ◽  
Vol 92 (4) ◽  
pp. 253-259 ◽  
Author(s):  
JULIETA GOENAGA ◽  
JUAN JOSÉ FANARA ◽  
ESTEBAN HASSON
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Correlations ◽  
Natural Populations ◽  
Food Shortage ◽  
Population Variation ◽  
Phenotypic Variance ◽  
Starvation Resistance ◽  
Natural Genetic Variation ◽  
Quantitative Genetic ◽  
Variation Explained

SummaryFood shortage is a stress factor that commonly affects organisms in nature. Resistance to food shortage or starvation resistance (SR) is a complex quantitative trait with direct implications on fitness. However, surveys of natural genetic variation in SR at different geographic scales are scarce. Here, we have measured variation in SR in sets of lines derived from nine natural populations of Drosophila melanogaster collected in western Argentina. Our study shows that within population variation explained a larger proportion of overall phenotypic variance (80%) than among populations (7·2%). We also noticed that an important fraction of variation was sex-specific. Overall females were more resistant to starvation than males; however, the magnitude of the sexual dimorphism (SD) in SR varied among lines and explained a significant fraction of phenotypic variance in all populations. Estimates of cross-sex genetic correlations suggest that the genetic architecture of SR is only partially shared between sexes in the populations examined, thus, facilitating further evolution of the SD.

Using AFLP markers to inform population management of the endemic Chatham Island toetoe, Austroderia turbaria (Poaceae).

2012 ◽  
Vol 18 (1) ◽  
pp. 33 ◽  
Author(s):  
Gary J Houliston ◽  
Murray I Dawson ◽  
Peter J De Lange ◽  
Peter B Heenan
Keyword(s):  
Management Practices ◽  
Flow Cytometric Analysis ◽  
Natural Populations ◽  
Source Material ◽  
Population Variation ◽  
Population Genetic Analysis ◽  
Flow Cytometric ◽  
Length Polymorphisms ◽  
Amplified Fragment Length Polymorphisms ◽  
Low Levels

Austroderia turbaria Connor is a threatened grass endemic to the Chatham Islands. Although formerly more widespread, remaining natural populations consist of highly fragmented remnants and/or individuals. Population genetic analysis of seed-raised progeny from six of the extant natural populations on Chatham and Pitt islands, using amplified fragment length polymorphisms (AFLPs) and microsatellite markers, shows that there are very low levels of variation (expected estimated heterozygosity He 0.023–0.030, no. of effective alleles Na 1.039–1.053), and no significant differentiation within or between populations on the two islands. Flow cytometric analysis of endosperm to embryo ratios suggests a sexual breeding system. This lack of population variation and no discernable differences between the two islands suggest that management practices such as the establishment of new populations can be carried out irrespective of the location of source material. One caveat to this is the possibility of Fusarium wilt occurring on the islands, in which case measures should be taken to best prevent spread across the range of the species.

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