EVOLUTION OF RESISTANCE TO A MULTIPLE-HERBIVORE COMMUNITY: GENETIC CORRELATIONS, DIFFUSE COEVOLUTION, AND CONSTRAINTS ON THE PLANT'S RESPONSE TO SELECTION

Evolution ◽  
2013 ◽  
Vol 67 (6) ◽  
pp. 1767-1779 ◽  
Author(s):  
Michael J. Wise ◽  
Mark D. Rausher
Keyword(s):  
Genetic Correlations ◽  
Response To Selection ◽  
Community Genetic ◽  
Herbivore Community ◽  
Evolution Of Resistance ◽  
Diffuse Coevolution

Measurement of fleece wettability in sheep and its relationship to susceptibility to fleece rot and blowfly strike

1982 ◽  
Vol 33 (1) ◽  
pp. 141 ◽  
Author(s):  
L Pascoe
Keyword(s):  
Genetic Variance ◽  
Additive Genetic Variance ◽  
Genetic Correlations ◽  
Economic Importance ◽  
Correlated Response ◽  
Response To Selection ◽  
Significant Incidence ◽  
The Mean ◽  
Selection For ◽  
The One

Fleece wettability in sheep is a character believed to be related to susceptibility to fleece rot and blowfly strike. The present study was undertaken to investigate that hypothesis and to assess wettability as a possible character for a selection program. Wool samples were taken from two flocks which had been subject to selection for wool quality and resistance to fleece rot and a third flock which was unselected. The wettabilities of about 800 samples were determined. The results were found to be repeatable and the technique was capable of distinguishing between sheep. Some problems of measurement are discussed. In the one flock with a significant incidence of fleece rot, susceptibility to fleece rot was found to be associated with higher wettabilities. The mean wettability and the variance were found to be significantly higher in the unselected flock than in the two selected flocks. The heritability of wettability was estimated in the two selected flocks and was found to be low. It is argued that there is likely to be more additive genetic variance in the unselected flock and that the observed difference in wettability was due to a correlated response to selection for resistance to fleece rot. It is considered that further work on the heritability of wettability and its genetic correlations with other characters of economic importance could be fruitful.

scholarly journals Conservation and Convergence of Genetic Architecture in the Adaptive Radiation ofAnolislizards

2021 ◽  
Author(s):  
Joel W. McGlothlin ◽  
Megan E. Kobiela ◽  
Helen V. Wright ◽  
Jason J. Kolbe ◽  
Jonathan B. Losos ◽  
...  
Keyword(s):  
Adaptive Radiation ◽  
Genetic Architecture ◽  
Recurrent Selection ◽  
Phylogenetic Signal ◽  
Genetic Correlations ◽  
Greater Antilles ◽  
Evolutionary Constraint ◽  
Response To Selection ◽  
Repeated Evolution ◽  
Habitat Specialists

ABSTRACTTheGmatrix, which quantifies the genetic architecture of traits, is often viewed as an evolutionary constraint. However,Gcan evolve in response to selection and may also be viewed as a product of adaptive evolution. The evolution of similarGmatrices in similar environments would suggest thatGevolves adaptively, but it is difficult to disentangle such effects from phylogeny. Here, we use the adaptive radiation ofAnolislizards to ask whether convergence ofGaccompanies the repeated evolution of habitat specialists, or ecomorphs, across the Greater Antilles. We measuredGin seven species representing three ecomorphs (trunk-crown, trunk-ground, and grass-bush). We found that the overall structure ofGdoes not converge. Instead, the structure ofGis well conserved and displays a phylogenetic signal. However, several elements ofGshowed signatures of convergence, indicating that some aspects of genetic architecture have been shaped by selection. Most notably, genetic correlations between limb traits and body traits were weaker in long-legged trunk-ground species, suggesting effects of recurrent selection on limb length. Our results demonstrate that common selection pressures may have subtle but consistent effects on the evolution ofG, even as the overall pattern of genetic architecture remains conserved.

Direct response to selection for post-weaning net feed intake in mice and correlated responses in post-weaning growth, intake, gross digestibility and body composition

2004 ◽  
Vol 44 (5) ◽  
pp. 489 ◽  
Author(s):  
T. E. Hughes ◽  
W. S. Pitchford
Keyword(s):  
Body Composition ◽  
Feed Intake ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Response To Selection ◽  
Correlated Responses ◽  
Direct Response ◽  
Selection For ◽  
Seven Generations ◽  
Daily Gain

Seven generations of divergent selection on a phenotypic index of net feed in mice produced a realised heritability estimate of 0.27 ± 0.07. Despite small negative genetic correlations of net feed intake with daily gain and liveweight, correlated responses in these economically important traits were negligible. Still, more efficient animals tended to be fatter during the early post-weaning phase. Gross digestibility was also affected, which may have implications for the overall energy balance of a biological system.

Heritability, correlated response, and indirect selection involving spectral reflectance indices and grain yield in wheat

2007 ◽  
Vol 58 (5) ◽  
pp. 432 ◽  
Author(s):  
M. A. Babar ◽  
M. van Ginkel ◽  
M. P. Reynolds ◽  
B. Prasad ◽  
A. R. Klatt
Keyword(s):  
Grain Yield ◽  
Spectral Reflectance ◽  
Genetic Correlations ◽  
Grain Filling ◽  
Indirect Selection ◽  
The Other ◽  
Correlated Response ◽  
Response To Selection ◽  
Selection For ◽  
Reflectance Indices

The objectives of this study were to assess the potential of using spectral reflectance indices (SRIs) as an indirect selection tool for grain yield in wheat under irrigated conditions. This paper demonstrates the genetic correlation between grain yield and SRIs, heritability and expected response to selection for grain yield and SRIs, correlated response to selection for grain yield estimated from SRIs, and efficiency of indirect selection for grain yield using SRIs in different spring wheat populations. Four field experiments, GHIST (15 CIMMYT globally adapted genotypes), RLs1 (25 random F3-derived families), RLs2 (36 random F3-derived families), and RLs3 (64 random F5-derived families) were conducted under irrigated conditions at the CIMMYT research station in north-west Mexico in 3 different years. Spectral reflectance was measured at 3 growth stages (booting, heading, and grain filling) and 7 SRIs were calculated using average values of spectral reflectance at heading and grain filling. Five previously developed SRIs (PRI, WI, RNDVI, GNDVI, SR), and 2 newly calculated SRIs (NWI-1 and NWI-2) were evaluated in the experiments. In general, the within- and between-year genetic correlations between grain yield and SRIs were significant. Three NIR-based indices (WI, NWI-1, and NWI-2) showed higher genetic correlations (0.73–0.92) with grain yield than the other indices (0.35–0.67), and these observations were consistent in all populations. Broad-sense heritability estimates for all indices were in general moderate to high (0.60–0.80), and higher than grain yield (0.45–0.70). The realised heritability for the 3 NIR-based indices was higher than for the other indices and for grain yield itself. Expected response to selection for all indices was moderate to high (0.54–0.85). The correlated response for grain yield estimated from the 3 NIR-based indices (0.59–0.64) was much higher than the correlated response for grain yield estimated from the other indices (0.31–0.46), and the efficiency of indirect selection for these 3 NIR-based indices was 90–96% of the efficiency of direct selection for grain yield. These results demonstrate the potential for using the 3 NIR-based SRI tools in breeding programs for selecting for increased genetic gains for yield.

Correlated response to selection for some egg performance traits in egg line of Japanese quail

2016 ◽  
Vol 56 (5) ◽  
pp. 913 ◽  
Author(s):  
B. Y. F. Mahmoud ◽  
G. Abou Khadiga ◽  
E. A. El-Full
Keyword(s):  
Japanese Quail ◽  
Egg Production ◽  
Genetic Correlations ◽  
Production Performance ◽  
Egg Mass ◽  
Correlated Response ◽  
Selection Experiment ◽  
Production Traits ◽  
Response To Selection ◽  
Female Line

Estimation of correlated response to selection in female line of Japanese quail after a short-term selection experiment was conducted. The total number of 547 female (275 selected and 272 control) Japanese quail included in the selection experiment of selection depended on aggregate breeding values based on animal model Best Linear Unbiased Prediction. Correlated selection response estimates were favourable for all the studied traits and significant (–0.38, –9.89, –12.86, –16.64, –5.08 and –8.24) for first egg weight (FEW), age at the first 10 eggs (AGE10), age at first 30 eggs (AGE30), age at first 60 eggs (AGE60), days needed to produce the first 30 eggs (DN30) and the first 60 eggs (DN60), respectively. Estimates of heritability were moderate for egg mass for the first 10 eggs (EM10), the first 30 eggs (EM30), the first 60 eggs (EM60), AGE10 and AGE30 (0.17–0.30), but low for AGE60, DN30 and DN60 (0.01–0.10). Genetic correlations between the selection criteria traits (AFE, BWSM and DN10) and the studied egg production traits were positive and ranged from 0.25 to 0.97, 0.24 to 0.95 and 0.06 to 0.98 for AFE, BWSM and DN10, respectively, whereas phenotypic correlations ranged from 0.12 to 0.89, 0.01 to 0.34 and 0.06 to 0.87 for the same traits. The favourable genetic response obtained for egg traits could be an indicator for improving egg production performance in Japanese quail.

RESPONSE TO SELECTION FOR WEIGHT-PER-DAY-OF-AGE IN RAMBOUILLET AND ROMNELET SHEEP

1975 ◽  
Vol 55 (1) ◽  
pp. 1-8 ◽  
Author(s):  
J. A. VESELY ◽  
H. F. PETERS
Keyword(s):  
Genetic Correlations ◽  
Response To Selection ◽  
Correlated Responses ◽  
Weaning Weight ◽  
Two Generations ◽  
Selection For ◽  
Heritability Estimates

Responses to selection for weight-per-day-of-age (WPDA) to about 170 days in Rambouillet and Romnelet sheep over 5 yr, comprising two generations, were measured by two methods. Correlated responses in weaning weight (WW) at about 100 days, and postweaning gain (PWG) for 70 days were also estimated. The estimates of annual genetic increases in WPDA were quite similar in both breeds and from both methods. The improvements of this trait in Rambouillet and Romnelet were estimated as 9.7 and 6.0 g/yr from method 1, and 9.1 and 7.8 g/yr from method II. Estimates of correlated responses in PWG obtained by both methods and in both breeds were close to expected estimates, but correlated responses in WW appeared to be overestimated. Heritability estimates for WPDA using paternal half-sibs were 0.20 for Rambouillet and 0.18 for Romnelet. All genetic correlations among the three traits were positive. Realized heritabilities for WPDA were 0.28 and 0.20 in Rambouillet and Romnelet by method I, and 0.26 in both breeds by method II.

scholarly journals Genetic variation and response to selection for storage root dry matter and associated traits in a population of yam bean (Pachyrhizus spp.) interspecies crosses

Euphytica ◽  
2021 ◽  
Vol 217 (4) ◽  
Author(s):  
Rolland Agaba ◽  
Patrick Rubaihayo ◽  
Phinehas Tukamuhabwa ◽  
Robert O. M. Mwanga ◽  
Silver Tumwegamire ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Coefficient Of Variation ◽  
Dry Matter ◽  
Block Design ◽  
Genetic Correlations ◽  
Storage Root ◽  
Response To Selection ◽  
Genetic Progress ◽  
Narrow Sense Heritability ◽  
High Dry Matter

AbstractThe goal of yam bean improvement in Africa is to develop superior high yielding and high dry matter cultivars that are preferred for adoption. In this study, the estimates of variance components, heritability and response to selection were studied in F3 yam bean families selected from interspecies crosses targeting improvement of storage root dry matter and associated traits. Breeding populations were generated using North Carolina II (NC II) mating design involving high dry matter P. tuberosus chuin cultivar, low dry matter P. ahipa and the high yielding P. erosus yam beans. The progenies were advanced through selfing from F1 to F2 population and then exposed to selection at 10% selection intensity to obtain 83 high dry matter lines. The selected lines were evaluated in an F3 trial using a randomized complete block design (RCBD) with three replications at the National Crops Resources Research Institute (NaCRRI) Namulonge, in Central Uganda. The results revealed significant (P < 0.001) genetic variation for storage root dry matter (RDM), storage root fresh yield (RFY), storage root dry yield (RDY), vine yield (VNY), fresh biomass yield (FBY), harvest index (HI), starch (STA) and protein (PRO) content. High genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) were obtained for VNY, RDY, FBY, RFY, RDM and STA. Narrow sense heritability was higher than 0.5 and response to selection was 15.5 to 33.1 for RDM, RFY, RDY, VNY, FBY and STA, indicating rapid genetic progress is achievable and early generation selection would be effective to improve these traits. Significant (P < 0.01) positive genetic correlations were observed between RDM, RDY, RFY, VNY, FBY and STA ranging from 0.422 to 0.963 implying that simultaneous improvement of these traits is possible in the current yam bean populations.

scholarly journals Additive Genetic Effects for Resistance to Foliar Powdery Mildew in Strawberry Revealed through Divergent Selection

2014 ◽  
Vol 139 (3) ◽  
pp. 310-316
Author(s):  
Colleen Kennedy ◽  
Luis F. Osorio ◽  
Natalia A. Peres ◽  
Vance M. Whitaker
Keyword(s):  
Powdery Mildew ◽  
Genetic Correlations ◽  
Breeding Population ◽  
Field Trials ◽  
Divergent Selection ◽  
Response To Selection ◽  
Additive Variance ◽  
Susceptible Population ◽  
High Heritability ◽  
Selection For

Powdery mildew (PM) of strawberry (Fragaria sp.) is a ubiquitous, wind-spread disease caused by the obligate parasite Podosphaera aphanis. To control PM, multiple fungicide applications are necessary each season, and none of the major cultivars in Florida have high levels of resistance. Therefore, the objectives of this study were to observe the response to selection and to estimate genetic parameters for PM and related traits in the University of Florida breeding population. In 2010, clonally replicated individuals from seven biparental crosses arising from 11 parents were included in a field trial in which clonally replicated seedlings were evaluated visually for percent coverage of PM mycelium using a modified Horsfall-Barratt scale of 0 to 6. Broad- (H2) and narrow-sense (h2) heritabilities for PM score were (mean ± se) 0.50 ± 0.08 and 0.40 ± 0.39, respectively, for the base population. After the second round of selection in the resistant population, no additive variance was detected, indicating that alleles for PM resistance had become fixed. In contrast, after two rounds of divergent selection in the susceptible population, there remained considerable additive variance (h2 = 0.42 ± 0.65). Moderate to high heritability estimates and a clear response to selection indicate that resistance to PM is genetically controlled through mostly additive effects. Selection of parents based on field trials with natural inoculum should result in good progress toward more resistant cultivars. The consistently moderate to strong genotypic and genetic correlations among PM and canopy density (CD) indicate that selection for PM resistance will result in reduced CD. Therefore, CD must be monitored over successive rounds of selection for low levels of PM to prevent CD falling below the commercially acceptable range.

Heritability and genotypic and environmental correlations of creeping root and persistency in Medicago sativa L.

1968 ◽  
Vol 19 (1) ◽  
pp. 27 ◽  
Author(s):  
H Daday
Keyword(s):  
Medicago Sativa ◽  
Plant Density ◽  
Genetic Correlations ◽  
Response To Selection ◽  
Environmental Correlations ◽  
Continuous Grazing ◽  
Medicago Sativa L ◽  
River Plants

This study examines the relationships between creeping-rootedness, plant diameters, and persistency in lucerne. Highly significant positive genetic correlations were found between all three plant characters among families under continuous grazing. The investigations disclosed several trends in genetic and environmental correlations, the significance of which is discussed. The heritabilities for the proportion I of creeping plants (0.41), plant diameter (0.32–0.45), and survival (0.23–0.46) were all high, indicating that response to selection is possible. The results showed that plant density decreased under continuous grazing; 66% of the creeping-rooted plants but only 8% of Hunter River plants survived after 17 months of continuous grazing.

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