scholarly journals Do genetic differences in growth thermal reaction norms maintain genetic variation in timing of diapause induction?

2019 ◽  
Author(s):  
Erlend I. F. Fossen ◽  
Joost A. M. Raeymaekers ◽  
Sigurd Einum
Keyword(s):  
Genetic Variation ◽  
Growth Performance ◽  
Genetic Correlation ◽  
Thermal Reaction ◽  
Genetic Differences ◽  
Diapause Induction ◽  
Reaction Norms ◽  
List Type ◽  
Environment Interaction ◽  
Sexual Production

AbstractAn optimal timing for diapause induction through the sexual production of dormant propagules is expected in populations of annual organisms. Yet, experimental work typically finds high within-population genetic variation in the sexual production of such propagules. Thus, high genetic variation in timing for diapause induction should be a common feature of annual organisms.Here, we hypothesize that genetic variation in the propensity to produce diapause propagules, Pd, is maintained by a genotype-by-environment interaction in growth performance, where fast-growing genotypes within an environment should delay diapause relative to slow-growing genotypes. From this, we derive two predictions. First, if there is ecological crossover in growth performance, the genetic correlation of Pd between environments should be negative. Second, the correlation between absolute plasticities of growth and Pd should be negative.We tested these predictions by quantifying ephippia production in genotypes of a population of the facultative sexual cladoceran Daphnia magna at two temperatures. The population biomass at the onset of ephippia production was used as a measure of Pd, whereas somatic growth rate was used to quantify growth. Plasticity for both measurements was derived from thermal reaction norms.Our results did not support either prediction, as neither the genetic correlation of Pd between environments, nor the correlation between absolute plasticity of growth and Pd were found to be significant.Our results suggest that genetic variation in the timing of diapause is not maintained by genetic differences in thermal growth reaction norms. We propose as an alternative hypothesis that if there is across year variation in how stochastically the environment deteriorates, fluctuating selection may favor genotypes with different Pd between years.

scholarly journals Do genetic differences in growth thermal reaction norms maintain genetic variation in timing of diapause induction?

2021 ◽  
Author(s):  
Erlend I. F. Fossen ◽  
Joost A. M. Raeymaekers ◽  
Sigurd Einum
Keyword(s):  
Genetic Variation ◽  
Thermal Reaction ◽  
Genetic Differences ◽  
Diapause Induction ◽  
Reaction Norms

Genotype by environment interaction for yearling weight in Nellore cattle applying reaction norms models

2018 ◽  
Vol 58 (11) ◽  
pp. 1996
Author(s):  
S. Ribeiro ◽  
J. P. Eler ◽  
V. B. Pedrosa ◽  
G. J. M. Rosa ◽  
J. B. S. Ferraz ◽  
...  
Keyword(s):  
Genetic Correlation ◽  
Environmental Gradient ◽  
Genotype By Environment Interaction ◽  
Reaction Norms ◽  
Breeding Value ◽  
Environment Interaction ◽  
Genotype By Environment ◽  
Genotype Environment Interaction ◽  
Nellore Cattle ◽  
Gradient Variation

In the present study, a possible existence of genotype × environment interaction was verified for yearling weight in Nellore cattle, utilising a reaction norms model. Therefore, possible changes in the breeding value were evaluated for 46 032 animals, from three distinct herds, according to the environmental gradient variation of the different contemporary groups. Under a Bayesian approach, analyses were carried out utilising INTERGEN software resulting in solutions of contemporary groups dispersed in the environmental gradient from –90 to +100 kg. The estimates of heritability coefficients ranged from 0.19 to 0.63 through the environmental gradient and the genetic correlation between intercept and slope of the reaction norms was 0.76. The genetic correlation considering all animals of the herds in the environmental gradient ranged from 0.83 to 1.0, and the correlation between breeding values of bulls in different environments ranged from 0.79 to 1.0. The results showed no effect of genotype × environment interaction on yearling weight in the herds of this study. However, it is important to verify a possible influence of the genotype × environment in the genetic evaluation of beef cattle, as different environments might cause interference in gene expression and consequently difference in phenotypic response.

The ecology and genetics of fitness in Chlamydomonas . I. Genotype-by-environment interaction among pure strains

1990 ◽  
Vol 240 (1298) ◽  
pp. 295-321 ◽  
Keyword(s):  
Environmental Factors ◽  
Genetic Correlation ◽  
Nonlinear Effects ◽  
Reaction Norms ◽  
Relative Fitness ◽  
Environment Interaction ◽  
Empirical Results ◽  
Genotype By Environment ◽  
The Difference ◽  
Interaction Variance

Strains of Chlamydomonas were cultured in different macroenvironments created by manipulating levels of nitrate, phosphate and bicarbonate in liquid growth media. Cell density, measured by optical transmittance, increased in a density-regulated manner, permitting the logistic par­ameters r and K to be estimated for each genotype–environment combination. The main empirical results of a factorial experiment were as follows. (i) A large proportion of the overall genotypic variance in fitness measures was attributable to genotype-by-environment (G × E) interaction: 65 % for r and 50 % for K . Variance components for r and K were uncorrelated, but components of the interaction variance may have been correlated with corresponding components of the environmental variance, such that the relative fitness of genotypes was most strongly affected by environmental factors that have the greatest effect on average fitness. Higher-order interactions were as large as lower-order interactions, so that relative fitness was sensitive to particular combinations of environmental factors as well as to their main effects. The covariance of r with K also showed strong G × E interaction, being negative in some macroenvironments and zero in others. (ii) An ‘environmental’ decomposition of the G × E interaction vari­ance separates ‘inconsistency’, due to lack of complete correlation between genotypes over macroenvironments, from ‘responsiveness’, due to differences between environmental variances among genotypes. Inconsistency was much the larger component for both r and K , showing that the greater part of the interaction variance was created by changes in the ranking of genotypes with respect to fitness between macroenvironments. When reaction norms were defined as the linear regressions of genotypic value on mean environmental value, substantial variance among reaction norms was detected : nonlinear effects were also large. (ii) A ‘genetic’ decomposition of the G × E interaction variance separates a component due to lack of complete genetic correlation from one due to differences in genetic variance. Incomplete genetic correlation was much the larger effect, the mean correlation between genotypes in two macroenvironments being only about +0.23 for r and +0.45 for K . A very striking observation was that the genetic correlation decreased as the difference between environments increased. It declined from +0.31 (for r ; + 0.58 for K ) when one factor differed between macroenvironments to +0.18 ( + 0.40) when two factors differed, and to +0.13 ( + 0.24) when all three factors differed. Furthermore, the genetic correlation varied inversely with the difference between environmental values, approaching zero when this difference was maximal. A measure of environmental consistency was obtained by plotting the score of a genotype in a given macroenvironment on its mean score over all macroenvironments, to identify environments in which generally inferior genotypes performed relatively well and vice versa. This analysis revealed some differences between macroenvironments, but nonlinear effects were again large. (iv) The two major empirical results of this investigation were ( a ) that much of the variance in fitness among genotypes is due to G × E inter­action caused by incomplete genetic correlation, and ( b ) that genetic correlation is smaller between environments that are less similar. Both the relevance and the limitations of these findings with respect to the interpretation of diversity are discussed.

Family variation in photosynthesis of 22-year-old black spruce: a test of two models of physiological response to water stress

1996 ◽  
Vol 26 (11) ◽  
pp. 1922-1933 ◽  
Author(s):  
John E. Major ◽  
Kurt H. Johnsen
Keyword(s):  
Genetic Variation ◽  
Soil Moisture ◽  
Water Potential ◽  
Black Spruce ◽  
Alternative Hypothesis ◽  
Genetic Differences ◽  
Environment Interaction ◽  
Physiological Measurement ◽  
Genotype Environment Interaction ◽  
Moisture Conditions

Gas exchange and water potential were measured in 22-year-old black spruce (Piceamariana (Mill.) BSP) trees from four full-sib families on two sites (one drier and one wetter) at the Petawawa National Forestry Institute, Ontario. Based on an observed genotype × environment interaction and earlier work with seedlings, a hypothesis was formed that at high soil moisture availability, no genetic differences in net photosynthesis (Pn) would exist and as soil moisture decreases, genetic differences in Pn would increase. From results of initial research with mature trees we formed an alternative hypothesis that genetic differences in Pn are constantly maintained under an array of soil moisture conditions. The two models were rigorously tested over a range of soil moisture conditions using two physiological measurement crews who switched sites throughout the day. Second-year foliage Pn of mature black spruce was more affected by nonstomatal limitations than by stomatal limitations. Progeny of one female had 12.5% and 7.4% higher Pn than progeny of another female on the dry and wet site, respectively. Genetic variation in Pn was consistent over a range of soil water potential. Thus, the first hypothesis was rejected in favor of the alternative hypothesis. Genetic variation in Pn appeared to be due to differential response to vapor pressure deficit. Suggestions as to how to reconcile the observed genotype × environment interaction in growth with the genetic differences in Pn are discussed.

scholarly journals From individuals to populations: How intraspecific competition shapes thermal reaction norms

2019 ◽  
Author(s):  
François Mallard ◽  
Vincent Le Bourlot ◽  
Christie Le Coeur ◽  
Monique Avnaim ◽  
Romain Péronnet ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Intraspecific Competition ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Effect Of Temperature ◽  
Dominant Factor ◽  
List Type ◽  
Joint Effects ◽  
Effects Of Temperature

AbstractMost ectotherms follow the temperature-size rule (TSR): in cold environments individuals grow slowly but reach a large asymptotic length. Intraspecific competition can induce plastic changes of growth rate and asymptotic length and competition may itself be modulated by temperature.Our aim is to disentangle the joint effects of temperature and intraspecific competition on growth rate and asymptotic length.We used two distinct clonal lineages of the Collembola Folsomia candida, to describe thermal reaction norms of growth rate, asymptotic length and reproduction over 6 temperatures between 6°C and 29°C. In parallel, we measured the long-term size-structure and dynamics of populations reared under the same temperatures to measure growth rates and asymptotic lengths in populations and to quantify the joint effects of competition and temperature on these traits.We show that intraspecific competition modulates the temperature-size rule. In dense populations there is a direct negative effect of temperature on asymptotic length, but there is no temperature dependence of the growth rate, the dominant factor regulating growth being competition. We fail to demonstrate that the strength of competition varies with temperature except at the lowest temperature where competition is minimal. The two lineages responded differently to the joint effects of temperature and competition and these genetic differences have marked effects on population dynamics along our temperature gradient.Our results reinforce the idea that the TSR response of ectotherms can be modulated by biotic and abiotic stressors when studied in non-optimal laboratory experiments. Untangling complex interactions between environment and demography will help understanding how size will respond to environmental change and how climate change may influence population dynamics.

scholarly journals Thermal reaction norms in sperm performance of Atlantic cod (Gadus morhua)

2010 ◽  
Vol 67 (3) ◽  
pp. 498-510 ◽  
Author(s):  
Craig F. Purchase ◽  
Ian A.E. Butts ◽  
Alexandre Alonso-Fernández ◽  
Edward A. Trippel
Keyword(s):  
Phenotypic Plasticity ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Swimming Performance ◽  
Common Garden ◽  
Reaction Norm ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Experimental Unit ◽  
Environment Interaction

Phenotypic plasticity occurs when a genotype produces variable phenotypes under different environments; the shapes of such responses are known as norms of reaction. The genetic scale at which reaction norms can be determined is restricted by the experimental unit that can be exposed to variable environments. This has limited their description beyond the family level in higher organisms, thus hindering our understanding of differences in plasticity at the scale of the individual. Using a three-year common-garden experiment, we quantify reaction norms in sperm performance of individual genotypes within different families of Atlantic cod ( Gadus morhua ). Cod sperm showed phenotypic plasticity in swimming performance across temperatures (3, 6, 11, and 21 °C), but the pattern of the response depended upon how long sperm had been swimming (30, 60, 120, or 180 s), i.e., plasticity in plasticity. Sperm generally swam fastest at intermediate temperatures when first assessed at 30 s after activation. However, a significant genotype × environment interaction was present, indicating inter-individual differences in phenotypic plasticity. To our knowledge, this is the first study to describe variable sperm performance across environmental conditions as a reaction norm. The results have potential theoretical, conservation, and aquaculture implications.

scholarly journals Thermal reaction norms of key metabolic enzymes reflect divergent physiological and behavioral adaptations of closely related amphipod species

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lena Jakob ◽  
Kseniya P. Vereshchagina ◽  
Anette Tillmann ◽  
Lorena Rivarola-Duarte ◽  
Denis V. Axenov-Gribanov ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Lake Baikal ◽  
Enzyme Activities ◽  
Large Scale ◽  
Metabolic Enzymes ◽  
Thermal Reaction ◽  
Reaction Norms ◽  
Ecological Niches ◽  
Amphipod Species ◽  
Thermal Plasticity

AbstractLake Baikal is inhabited by more than 300 endemic amphipod species, which are narrowly adapted to certain thermal niches due to the high interspecific competition. In contrast, the surrounding freshwater fauna is commonly represented by species with large-scale distribution and high phenotypic thermal plasticity. Here, we investigated the thermal plasticity of the energy metabolism in two closely-related endemic amphipod species from Lake Baikal (Eulimnogammarus verrucosus; stenothermal and Eulimnogammarus cyaneus; eurythermal) and the ubiquitous Holarctic amphipod Gammarus lacustris (eurythermal) by exposure to a summer warming scenario (6–23.6 °C; 0.8 °C d−1). In concert with routine metabolic rates, activities of key metabolic enzymes increased strongly with temperature up to 15 °C in E. verrucosus, whereupon they leveled off (except for lactate dehydrogenase). In contrast, exponential increases were seen in E. cyaneus and G. lacustris throughout the thermal trial (Q10-values: 1.6–3.7). Cytochrome-c-oxidase, lactate dehydrogenase, and 3-hydroxyacyl-CoA dehydrogenase activities were found to be higher in G. lacustris than in E. cyaneus, especially at the highest experimental temperature (23.6 °C). Decreasing gene expression levels revealed some thermal compensation in E. cyaneus but not in G. lacustris. In all species, shifts in enzyme activities favored glycolytic energy generation in the warmth. The congruent temperature-dependencies of enzyme activities and routine metabolism in E. verrucosus indicate a strong feedback-regulation of enzymatic activities by whole organism responses. The species-specific thermal reaction norms reflect the different ecological niches, including the spatial distribution, distinct thermal behavior such as temperature-dependent migration, movement activity, and mating season.

scholarly journals Genetic evaluation of Devon Cattle using a reaction norms model

2010 ◽  
Vol 39 (1) ◽  
pp. 128-133 ◽  
Author(s):  
Marcela Bicca Bragança Corrêa ◽  
Nelson José Laurino Dionello ◽  
Fernando Flores Cardoso
Keyword(s):  
Environmental Gradient ◽  
Selection Process ◽  
Genotype By Environment Interaction ◽  
Reaction Norms ◽  
Environment Interaction ◽  
Improvement Program ◽  
Spearman Rank ◽  
Genotype By Environment ◽  
Conventional Animal ◽  
Selection Decision

The objective of this study was to evaluate differences in sire genetic values obtained by a conventional animal model (AM) and by a reaction norms hierarchical model (RNHM) that considers the genotype by environment interaction. A total of 25,500 records was used collected by PROMEBO - beef cattle improvement program of the National Breeders Association "Herd Book Collares" on Devon cattle born from 1980 though 2005. Post weaning gain 345 adjusted (PWG345) was the evaluated trait and the INTERGEN program was employed for data analysis. Reaction norms of the 25 sires with larger offspring showed ranking exchanges and scale effect in the environmental gradient. Spearman rank correlations between genetic values obtained by AM and RNHM at low, medium and high environmental levels were used to assess selection decision based on the different models. These correlations ranged from 0.12 and 0.99, therefore showing substantial changes in ranking, particularly between those genetic values obtained by the RNHM at low level compared to the same RNHM at medium and high levels and to AM, when considering the top 5% bulls. The results indicated that the selection process should consider the genotype by environmental interaction to maximize genetic gain and production of this population in each specific environment.

scholarly journals Canaryseed (Phalaris canariensis L.) accessions from nineteen countries show useful genetic variation for agronomic traits

2011 ◽  
Vol 91 (1) ◽  
pp. 37-48 ◽  
Author(s):  
M. Cogliatti ◽  
F. Bongiorno ◽  
H. Dalla Valle ◽  
W J Rogers
Keyword(s):  
Genetic Variation ◽  
Grain Yield ◽  
Harvest Index ◽  
Agronomic Traits ◽  
Grain Weight ◽  
Environment Interaction ◽  
Grain Number ◽  
Harvest Maturity ◽  
Phalaris Canariensis ◽  
Late Sowing

Fifty-seven accessions of canaryseed (47 populations and 10 cultivars) from 19 countries were evaluated for agronomic traits in four field trials sown over 3 yr in the province of Buenos Aires, Argentina. Genetic variation was found for all traits scored: grain yield and its components (grain weight, grain number per square meter, grain number per head and head number per square meter), harvest index, percent lodging, and phenological characters (emergence to heading, emergence to harvest maturity and heading to harvest maturity). Although genotype × environment interaction was observed for all traits, the additive differences between accessions were sufficient to enable promising breeding materials to be identified. Accessions superior in performance to the local Argentinean population, which in general gave values close to the overall mean of the accessions evaluated, were identified. For example, a population of Moroccan origin gave good yield associated with elevated values of the highly heritable character grain weight, rather than with the more commonly observed grain number per square meter. This population was also of relatively short stature and resistant to lodging, and, although it performed best when sown within the normal sowing date, tolerated late sowing fairly well. Other accessions were also observed with high grain weight, a useful characteristic in itself, since large grains are desirable from a quality point of view. Regarding phenology, the accessions showed a range of 160 degree days (8 calendar days in our conditions) in maturity, which, while not large in magnitude, may be of some utility in crop rotation management. Some accessions were well adapted to late sowing. Grain yield in general was strongly correlated with grain number per square meter. Principal components analysis (PCA) carried out for all characteristics provided indications of accessions combining useful characteristics and identified three components that explained approximately 70% of the phenotypic variation. Furthermore, a second PCA plus regression showed that approximately 60% of the variation in grain yield could be explained by a component associated with harvest index and grain number per square meter. Pointers were provided to possible future breeding targets.Key words: Phalaris canariensis, canaryseed, accessions, yield, phenology, genetics, breeding

scholarly journals Variations in Growth Performance and Nitrogen Uptake of Sugarcane Cultivars Under Rain-Fed Conditions

2020 ◽  
Vol 3 (2) ◽  
pp. 571-579
Author(s):  
Dinh Thai Hoang ◽  
Hiroo Takaragawa ◽  
Le Trong Lu ◽  
Eizo Taira ◽  
Yoshinobu Kawamitsu
Keyword(s):  
Genetic Variation ◽  
Growth Performance ◽  
Leaf Area ◽  
Nitrogen Uptake ◽  
Yield Components ◽  
Water Shortage ◽  
Cane Yield ◽  
Total Biomass ◽  
High Nitrogen ◽  
Sugarcane Varieties

The experiment was conducted to evaluate growth and nitrogen uptake of the twelve sugarcane varieties, viz. NiF3, NiF8, Ni9, Ni12, Ni15, Ni17, Ni21, Ni22, Ni25, Ni27, Ni28, and Ni29, under rain-fed conditions during the period from 70 to 160 days after transplanting (DAT) at the experimental field, Faculty of Agriculture, University of the Ryukyus, Okinawa, Japan. The results showed that water shortage from a rain-fed condition caused reductions, but not significant in plant height and SPAD of sugarcane varieties. The genetic variation in leaf area, yield components, partial and total biomass, and cane yield was found among the investigated varieties. The positive associations between total nitrogen uptake with total biomass production and cane yield suggested that higher nitrogen uptake supports better growth performance of sugarcane under rain-fed conditions. From this study, NiF3 and Ni27 could be introduced as the promising sugarcane varieties for better growth performance and high nitrogen uptake under rain-fed conditions.

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