Genetic variation, genotype × environment interaction, and selection for tipburn resistance in lettuce in multi-environments

Euphytica ◽  
2009 ◽  
Vol 171 (3) ◽  
pp. 427-439 ◽  
Author(s):  
Sylvie Jenni ◽  
Ryan J. Hayes
Keyword(s):  
Genetic Variation ◽  
Environment Interaction ◽  
Genotype Environment Interaction ◽  
Selection For

scholarly journals Multiple layers of cryptic genetic variation underlie a yeast complex trait

2018 ◽  
Author(s):  
Jonathan T Lee ◽  
Alessandro L V Coradini ◽  
Amy Shen ◽  
Ian M Ehrenreich
Keyword(s):  
Genetic Variation ◽  
Complex Trait ◽  
Environment Interaction ◽  
Coding Region ◽  
Cryptic Genetic Variation ◽  
Genotype Environment Interaction ◽  
Genetic Perturbations ◽  
In Cis ◽  
The Relationship ◽  
Surface Gene

Cryptic genetic variation may be an important contributor to heritable traits, but its extent and regulation are not fully understood. Here, we investigate the cryptic genetic variation underlying a Saccharomyces cerevisiae colony phenotype that is typically suppressed in a cross of the lab strain BY4716 (BY) and a derivative of the clinical isolate 322134S (3S). To do this, we comprehensively map the trait's genetic basis in the BYx3S cross in the presence of three different genetic perturbations that enable its expression. This allows us to detect and compare the specific loci harboring cryptic genetic variants that interact with each perturbation. In total, we identify 21 loci, all but one of which interacts with just a subset of the perturbations. Beyond impacting which loci contribute to the trait, the genetic perturbations also influence the extent of additivity, epistasis, and genotype-environment interaction among the detected loci. Additionally, we show that the single locus interacting with all three perturbations corresponds to the coding region of the cell surface gene FLO11. Nearly all of the other loci influence FLO11 transcription in cis or trans. However, the perturbations reveal cryptic genetic variation in different pathways and sub-pathways upstream of FLO11, suggesting that multiple layers of cryptic genetic variation with highly contextual effects underlie the trait. Our work demonstrates an abundance of cryptic genetic variation in transcriptional regulation and illustrates how this cryptic genetic variation complicates efforts to study the relationship between genotype and phenotype.

scholarly journals Challenges and adaptive strategies in pig breeding from the aspect of heat stress and heat tolerance

2020 ◽  
Vol 24 (1) ◽  
pp. 1-13
Author(s):  
István Nagy ◽  
György Kövér ◽  
Zsolt Gerencsér ◽  
Gabriella Szász
Keyword(s):  
Heat Tolerance ◽  
Temperature Effects ◽  
Selection Criteria ◽  
Relevant Literature ◽  
Genetic Selection ◽  
Adaptive Strategies ◽  
Environment Interaction ◽  
Genotype Environment Interaction ◽  
Selection For ◽  
The Ideal

Authors summarized the results of the last three decades’ relevant literature examining the temperature effects on the various growth, reproductive and carcass traits in pigs. The ideal period of temperature measurement and the different methodologies characterizing temperature effects were summarized. The aspects of genotype environment interaction for the measured traits under hot and temperate conditions were also presented. Finally the possibilities of direct genetic selection for heat tolerance and its possible selection criteria traits were also discussed.

scholarly journals Genotype-environment interaction and the maintenance of genetic variation: an empirical study of Lobelia inflata (Campanulaceae)

2020 ◽  
Vol 7 (3) ◽  
pp. 191720 ◽  
Author(s):  
Kristen Côté ◽  
Andrew M. Simons
Keyword(s):  
Genetic Variation ◽  
Balancing Selection ◽  
Rank Order ◽  
Empirical Test ◽  
Heterozygote Advantage ◽  
Environment Interaction ◽  
Fluctuating Selection ◽  
Long Term Study ◽  
Genotype Environment Interaction ◽  
Lobelia Inflata

High levels of genetic variation are often observed in natural populations, suggesting the action of processes such as frequency-dependent selection, heterozygote advantage and variable selection. However, the maintenance of genetic variation in fitness-related traits remains incompletely explained. The extent of genetic variation in obligately self-fertilizing populations of Lobelia inflata (Campanulaceae L.) strongly implies balancing selection. Lobelia inflata thus offers an exceptional opportunity for an empirical test of genotype-environment interaction (G × E) as a variance-maintaining mechanism under fluctuating selection: L. inflata is monocarpic and reproduces only by seed, facilitating assessment of lifetime fitness; genome-wide homozygosity precludes some mechanisms of balancing selection, and microsatellites are, in effect, genotypic lineage markers. Here, we find support for the temporal G × E hypothesis using a manipulated space-for-time approach across four environments: a field environment, an outdoor experimental plot and two differing growth-chamber environments. High genetic variance was confirmed: 83 field-collected individuals consisted of 45 distinct microsatellite lineages with, on average, 4.5 alleles per locus. Rank-order fitness, measured as lifetime fruit production in 16 replicated multilocus genotypes, changed significantly across environments. Phenotypic differences among microsatellite lineages were detected. Results thus support the G × E hypothesis in principle. However, the evaluation of the effect size of this mechanism and fitness effects of life-history traits will require a long-term study of fluctuating selection on labelled genotypes in the field.

Genetic improvement of early vigour in wheat

1999 ◽  
Vol 50 (3) ◽  
pp. 291 ◽  
Author(s):  
G. J. Rebetzke ◽  
R. A. Richards
Keyword(s):  
Genetic Variation ◽  
Leaf Area ◽  
Plant Biomass ◽  
Genetic Correlations ◽  
Yield Potential ◽  
Environment Interaction ◽  
Narrow Sense Heritability ◽  
Wheat Varieties ◽  
Early Vigour ◽  
Selection For

Grain yield potential of Australian wheat crops is often limited because of inadequate water for crop growth and grain filling. Greater early vigour, defined here as the amount of leaf area produced early in the season, should improve the water-use efficiency and yield of wheat crops grown in Mediterranean-type climates such as occurs in southern Australia. In order to maximise selection efficiency for early vigour in breeding programs, the magnitude and form of genetic variation for early vigour and its components was investigated for 2 contrasting wheat populations. The first population comprised 28 Australian and overseas wheat varieties evaluated in a serial sowing study in Canberra. The second population contained 50 random F 2:4 and F 2:6 families derived from a convergent cross of elite CIMMYT wheat lines evaluated in Canberra, and in the field at Condobolin, New South Wales. For the first population, environmental effects on leaf breadth and length, and to a lesser extent, phyllochron interval, produced significant (P < 0.05) changes in leaf area. Large and significant (P < 0.05) differences were observed among Australian and overseas wheats for early vigour and its components. Australian varieties were among the least vigorous of the lines tested, with a number of overseas varieties producing about 75% greater leaf area than representative Australian wheats. Increased leaf area was genetically correlated with increases in leaf breadth and length, and a longer phyllochron interval. Significant (P < 0.05) genotype ´ environment interaction reduced broad-sense heritability (%) for early vigour (H ± s.e., 87 ± 26) compared with leaf breadth (96 ± 25) and length (97 ± 27). Narrow-sense heritability (%) in the second population was small for leaf area (h2 ± s.e., 30 ± 6) and plant biomass (35 ± 7), but high for leaf breadth (76 ± 14) and length (67 ± 16). Genetic correlations were strong and positive for leaf area with plant biomass, leaf breadth and length, specific leaf area and coleoptile tiller frequency, whereas faster leaf and primary tiller production were negatively correlated with leaf area. The high heritability for leaf breadth coupled with its strong genetic correlation with leaf area (rg = 0.56-0.57) indicated that selection for leaf breadth should produce genetic gain in leaf area similar to selection for leaf area per se. However, the ease with which leaf breadth can be measured indicates that selection for this character either by itself, or in combination with coleoptile tiller production, should provide a rapid and non-destructive screening for early vigour in segregating wheat populations. The availability of genetic variation for early vigour and correlated traits should enable direct or indirect selection for greater leaf area in segregating wheat populations.

Detection and estimation of components of genetic variation and genotype × environment interaction in three wheat crosses

1984 ◽  
Vol 103 (3) ◽  
pp. 543-547 ◽  
Author(s):  
S. Singh ◽  
M. S. Dahiya
Keyword(s):  
Genetic Variation ◽  
Grain Yield ◽  
Plant Height ◽  
Environment Interaction ◽  
Gene Effects ◽  
Genotype Environment Interaction ◽  
Additive Component ◽  
Spike Number ◽  
Additive Gene ◽  
1000 Grain Weight

SummaryThe data obtained from 360 progeny families produced by crossing 40 F2 plants from each of three wheat crosses HD 2009 × HD 1949, Raj 821 × WH 147 and NP 876 × HD 1949, to three testers (the testers being the two parents of each original cross and their F1 in each case) were subjected to triple test cross analysis for detecting and estimating additive, dominance and epistatic components of genetic variation and interaction of these components with environment for plant height, spike length, number of tillers per plant, number of spikelets per spike, number of grains per spike, 1000-grain weight, number of days from sowing to heading and to maturity, grain yield per plant and grain yield/above ground dry matter ratio (harvest index). Epistasis was an important element for plant height, number of tillers per plant, number of grains per spike and grain yield per plant in all three crosses. Both the i type and j and l type epistasis were equally important. In general, the magnitude of additive component was larger than that of dominance component. The additive gene effects were more sensitive to environmental change than the dominance gene effects. Similarly, j and l type epistasis was relatively more sensitive to environment than the i type epistasis.

Genetic improvement of resistance to cyclaneusma needle cast in Pinus radiata

2019 ◽  
Vol 49 (2) ◽  
pp. 128-133 ◽  
Author(s):  
Mari Suontama ◽  
Yongjun Li ◽  
Charlie B. Low ◽  
Heidi S. Dungey
Keyword(s):  
New Zealand ◽  
Pinus Radiata ◽  
Genetic Improvement ◽  
Genetic Correlations ◽  
Tree Height ◽  
Progeny Testing ◽  
Environment Interaction ◽  
Needle Cast ◽  
Genotype Environment Interaction ◽  
Selection For

Progeny testing of resistance to needle loss caused by Cyclaneusma minus (cyclaneusma needle cast) has been included in the needle disease resistance strategy of Pinus radiata D. Don in New Zealand since the late 1970s. Data on progeny trials, two in the North Island of New Zealand and one in Tasmania, Australia, were available to estimate heritability between trait genetic correlations and genotype × environment interaction. Resistance to cyclaneusma needle cast had moderate estimates of heritability (0.25 to 0.46) at all sites. Genetic correlations between the assessed traits indicated that selection for faster early growth, i.e., tree height at age 4 years and diameter at breast height at age 6 years, favours trees that are prone to Cyclaneusma infection, while a favourable genetic association between resistance to cyclaneusma needle cast and productivity was evident at a later assessment at age 9 years. No significant genotype × environment interaction was found for resistance to cyclaneusma needle cast; however, stability of genotypes across a wider range of environments and with a high genetic connectedness requires more research. Considerable genetic improvement can be achieved for resistance to cyclaneusma needle cast and indirect selection for the trait should be pursued by selecting for productivity and culling susceptible genotypes from breeding.

Genetic Variation and Causes of Genotype-Environment Interaction in the Body Size of Blue Tit (Parus caeruleus)

Genetics ◽  
1998 ◽  
Vol 148 (3) ◽  
pp. 1233-1244 ◽  
Author(s):  
Juha Merilä ◽  
James D Fry
Keyword(s):  
Genetic Variation ◽  
Body Size ◽  
Genetic Variance ◽  
Natural Populations ◽  
The Body ◽  
Environment Interaction ◽  
Parus Caeruleus ◽  
Genotype Environment Interaction ◽  
The Poor ◽  
Good Environment

Abstract In several studies of natural populations of birds, the heritability of body size estimated by parent-offspring regression has been lower when offspring have developed in poor feeding regimens than when they developed in good feeding regimens. This has led to the suggestion that adaptation under poor regimens may be constrained by lack of genetic variation. We examined the influence of environmental conditions on expression of genetic variation in body size of nestling blue tits (Parus caeruleus) by raising full sibs in artificially reduced and enlarged broods, corresponding to good and poor feeding regimens, respectively. Individuals grown in the poor regimen attained smaller body size than their sibs grown in the good regimen. However, there was among-family variation in response to the treatments—i.e., genotype-environment interactions (GEIs). Partitioning the GEI variance into contributions attributable to (1) differences in the among-family genetic variance between the treatments and (2) imperfect correlation of genotypic values across treatments identified the latter as the main cause of the GEI. Parent-offspring regressions were not significantly different when offspring were reared in the good environment (h2 = 0.75) vs. when they were reared in the poor environment (h2 = 0.63). Thus, there was little evidence that genetic variance in body size was lower under the poor conditions than under the good conditions. These results do not support the view that the genetic potential for adaptation to poor feeding conditions is less than that for adaptation to good conditions, but they do suggest that different genotypes may be favored under the different conditions.

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