Estimation of phenotypic selection differentials for predicting genetic responses to ratio-based selection

Genome ◽  
1988 ◽  
Vol 30 (6) ◽  
pp. 838-843 ◽  
Author(s):  
D. E. Mather ◽  
F. C. Gunsett ◽  
O. B. Allen ◽  
L. W. Kannenberg
Keyword(s):  
Selection Criteria ◽  
Crop Improvement ◽  
Selection Criterion ◽  
Phenotypic Selection ◽  
Worked Examples ◽  
Genetic Response ◽  
Analysis And Evaluation ◽  
Selection For ◽  
Genetic Responses ◽  
Selection Differentials

Ratios of the phenotypic values of two traits may be used as selection criteria in animal and plant breeding to improve the ratio traits themselves or to effect changes in their two component (numerator and denominator) traits. Prediction of genetic responses to ratio-based selection would facilitate quantitative analysis and evaluation of selection based on ratios. Methods for predicting such responses are derived and presented here. They employ expressions for the truncation value of a ratio and for the phenotypic selection differentials of the numerator and denominator traits. The derivation of these expressions is based upon the assumption that the phenotypic values of each of these traits are normally distributed. Worked examples relating to livestock and crop improvement are included to demonstrate how responses to selection for ratios may be predicted.Key words: ratio selection criterion, selection differential, genetic response.

scholarly journals Hotel Selection Criteria of Solo Traveling Females

2020 ◽  
Vol 18 (2) ◽  
pp. 58-73
Author(s):  
Halimin Herjanto ◽  
◽  
Alexandra Chilicki ◽  
Chidchanok Anantamongkolkul ◽  
Erin McGuinness ◽  
...  
Keyword(s):  
Cell Phone ◽  
Selection Criteria ◽  
Academic Research ◽  
Selection Criterion ◽  
Product Evaluations ◽  
Purchasing Decisions ◽  
Study Results ◽  
Automated Teller Machine ◽  
Selection For ◽  
Cost Efficient

Consumers use online e-reviews as a popular tool for information and obtaining guidance. E-reviews have therefore become an important barometer in conducting product evaluations, and more importantly, to make purchasing decisions. This includes decisions about hotel selection. For hospitality industry marketers, the information in e-reviews is particularly important in translating and understanding consumer-specific needs. The current study brings valuable awareness to the limited academic research into hotel selection criteria among solo-traveling females. TripAdvisor’s top 25 list of cost-efficient hotels worldwide received 345 total consumer reviews. Noteworthy findings of the current study show unique selection criteria considered important to the solo traveling female including a hotel-provided cell phone programmed with emergency local contact information, and a nearby or on-premise automated teller machine. Study results also indicate that stewardship service, such as intimate and personalized hotel staff who “go the extra mile” is an important selection criterion. Also discussed are research limitations and implications.

scholarly journals Phenotypic selection in common toad (Bufo bufo)

2007 ◽  
Vol 59 (4) ◽  
pp. 327-333 ◽  
Author(s):  
Dragana Cvetkovic ◽  
Natasa Tomasevic ◽  
I. Aleksic ◽  
Andjelka Crnobrnja-Isailovic
Keyword(s):  
Natural Populations ◽  
Phenotypic Selection ◽  
Bufo Bufo ◽  
Leg Length ◽  
Regression Approach ◽  
Selection For ◽  
Correlated Characters ◽  
Toad Bufo ◽  
Toad Bufo Bufo ◽  
Selection Differentials

One of the most important problems for evolutionary biologists is to investigate the patterns and strength of phenotypic selection acting on quantitative traits in natural populations. Measurement of selection is complicated by the presence of correlations between characters; selection on a particular trait produces not only a direct effect, but indirect effects as well. Despite the growing body of phenotypic selection studies in a variety of taxa, studies on amphibians are still sparse. The aim of this study was to estimate patterns and strength of selection acting on a set of correlated characters in a natural population of Bufo bufo from the vicinity of Belgrade, Serbia. Morphological traits (body length, fore- and hind leg length) were measured, while fitness was assayed as fecundity and gonad weight for females and males, respec?tively. The regression approach was used to estimate selection differentials and gradients. Selection patterns differed between the sexes - linear selection differentials showed significant total directional selection for body size in females, but not in males. In males, differentials were significant for both fore- and hind leg lengths. Sample size did not permit identification of significant nonlinear (quadratic) selection.

The effect of correction factors on response to selection in beef cattle

1980 ◽  
Vol 30 (2) ◽  
pp. 211-216 ◽  
Author(s):  
L. P. Jones ◽  
I. R. Hopkins
Keyword(s):  
Growth Rate ◽  
Age Groups ◽  
Correction Factors ◽  
Response To Selection ◽  
Weaning Weight ◽  
Selection For ◽  
Rate Selection ◽  
Genetic Responses ◽  
Selection Differentials ◽  
Selection Of

ABSTRACTProgeny of younger dams grow more slowly than those of older dams. When the environmental effects of dam age are not allowed for in selection for growth rate, selection differentials and genetic responses to selection are reduced.In a model herd, with cows aged 2 to 8 years, it was found that neglecting the dam age effects reduced genetic gains by about 15% when selection is for weaning weight, and by 11 to 7 % when selection is at an age of 12 to 20 months. Much of the reduction occurs because of the selection of higher proportions from genetically inferior groups.If genetic differences among dam age groups are small the reduction is only 7% at weaning and less at older ages. The effect of ignoring calf age was also estimated. It was found that if calves born within a period of 33 days were compared and calf age was neglected, the response to selection for weaning weight would be reduced by about 6%.

scholarly journals Selection Criteria and Selection Environment for Drought Tolerance of Egyptian Wheat (Triticum aestivum L.) Landraces

2020 ◽  
pp. 25-40
Author(s):  
Ahmed Medhat Mohamed Al-Naggar ◽  
Mohamed Abd El-Maboud Abd El-Shafi ◽  
Mohamed Helmy El-Shal ◽  
Ali Hassan Anany
Keyword(s):  
Drought Tolerance ◽  
Grain Yield ◽  
Selection Criteria ◽  
Selection Criterion ◽  
Correlation Coefficients ◽  
Grain Filling ◽  
Triticum Aestivum L ◽  
Genetic Advance ◽  
Selection Environment ◽  
Selection For

Strong correlations between wheat traits and drought tolerance (DT) associated with high heritability and high genetic advance from selection would allow plant breeder to use such traits as selection criteria. The objective of the present investigation was to determine the optimum selection criteria and selection environment for drought tolerance via estimation of correlation coefficients (r) among 13 agronomic, grain yield and quality traits and DT of 20 wheat landraces, broad-sense heritability (h2b) and genetic advance (GA) from selection for such traits under well-watered (WW) and water stressed (WS) environments. A two-year experiment was carried out using a split-plot design with four replications. Results concluded that the best selection criterion for drought tolerance in our study was grain yield/plant (GYPP), followed by a number of grains/spike (GPS), grain filling period (GFP), grain starch (GSC) and protein (GPC) content, plant height (PH) and days to maturity (DTM), since they showed high (r), high h2b and high GA estimates. The best selection environment was WW for days to anthesis, PH, spikes/plant, GPS, spikelets/spike, GYPP, GPC and WS for DTM, GFP, GSC and thousand-grain weight traits. This information could help future breeding programs in selection for improving drought tolerance of wheat.

Recurrent Phenotypic Selection for Resistance to Brown Leaf Spot in Smooth Bromegrass 1

Crop Science ◽  
1986 ◽  
Vol 26 (3) ◽  
pp. 533-536 ◽  
Author(s):  
Clyde C. Berg ◽  
Robert T. Sherwood ◽  
Kenneth E. Zeiders
Keyword(s):  
Leaf Spot ◽  
Phenotypic Selection ◽  
Smooth Bromegrass ◽  
Brown Leaf Spot ◽  
Brown Leaf ◽  
Selection For

scholarly journals Introgression of Resistance to Leafminer (Liriomyza cicerina Rondani) from Cicer reticulatum Ladiz. to C. arietinum L. and Relationships between Potential Biochemical Selection Criteria

Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 57
Author(s):  
Nesrine Chrigui ◽  
Duygu Sari ◽  
Hatice Sari ◽  
Tuba Eker ◽  
Mehmet Fatih Cengiz ◽  
...  
Keyword(s):  
Organic Acids ◽  
Succinic Acid ◽  
Selection Criteria ◽  
Insect Pests ◽  
Recombinant Inbred Lines ◽  
Selection Criterion ◽  
Leaf Miner ◽  
Interspecific Crosses ◽  
Visual Scale ◽  
Resistant Varieties

The chickpea leafminer, Liriomyza cicerina (Rondani), is one of the most destructive insect pests of cultivated chickpea (Cicer arietinum L.) in the Mediterranean region under field conditions. For sustainable and environmentally friendly chickpea production, efforts have been devoted to managing the leafminer via decreasing the use of insecticides. Breeding of new resistant varieties is not only an efficient and practical approach, but also cost-effective and environmentally sensitive. To improve resistant varieties, breeders need reliable biochemical selection criteria that can be used in breeding programs. The first objective was to investigate the possible introgression of resistance to the leafminer from C. reticulatum Ladiz. (resistant) to C. arietinum (susceptible), then, to estimate inheritance of resistance to the leafminer for efficient breeding strategies, and finally, to study organic acid contents as selection criteria. Recombinant inbred lines (RILs) and their parents were evaluated using a visual scale of 1–9 (1 = free from leafminer damage and 9 = mines in more than 91% of the leaflets and defoliation greater than 31%) in the field under natural infestation conditions after the susceptible parent and check had scores of >7 on the visual scale. Superior RILs were found for resistance to the leafminer, and agro-morphological traits indicating that introgression of resistance to leaf miner from C. reticulatum to C. arietinum could be possible using interspecific crosses. The inheritance pattern of resistance to the leafminer in RILs was shown to be quantitative. Organic acids, including oxalic, malic, quinic, tartaric, citric and succinic acids in RILs grown in the field under insect epidemic conditions and in the greenhouse under non-infested conditions were detected by using high performance liquid chromatography (HPLC). In general, organic acids were found to be higher in resistant RILs than susceptible RILs. Path and correlation coefficients showed that succinic acid exhibited the highest direct effects on resistance to the leafminer. Multivariate analyses, including path, correlation and factor analyses suggested that a high level of succinic acid could be used as a potential biochemical selection criterion for resistance to leafminer in chickpea. Resistant RILs with a high seed yield resembling kabuli chickpea can be grown directly in the target environments under leaf miner infestation conditions.

Composite trait selection to improve reproduction and ewe productivity: a review

2009 ◽  
Vol 49 (1) ◽  
pp. 9 ◽  
Author(s):  
G. D. Snowder ◽  
N. M. Fogarty
Keyword(s):  
Individual Component ◽  
Genetic Relationships ◽  
Reproductive Efficiency ◽  
Component Trait ◽  
Litter Weight ◽  
Growth Selection ◽  
Component Traits ◽  
Selection For ◽  
Genetic Responses ◽  
Lamb Growth

Reproduction and ewe productivity are complex composite traits that are influenced by several component traits. Genetic improvement by selection for an individual component trait may not always be advantageous because adverse or neutral genetic relationships can exist among the component traits. Selection for an overall composite trait of ewe productivity, defined as litter weight weaned per ewe joined, can result in a balanced biological composite trait with favourable responses in component traits including fertility, number of lambs born, lamb survival, lactation and lamb growth. Selection for litter weight weaned may also overcome adverse genetic relationships among reproductive component traits. This review examines the genetic responses of selecting directly for litter weight weaned, compared with selection responses for one or more of its component traits. It is concluded that selection to improve reproductive efficiency and ewe productivity, under most production and environmental systems, would benefit from selection for a composite trait such as litter weight weaned, rather than for a single component trait.

Selection and response within the nucleus of a sheep group-breeding scheme

1990 ◽  
Vol 51 (3) ◽  
pp. 593-599 ◽  
Author(s):  
S. Anderson ◽  
M. K. Curran
Keyword(s):  
Litter Size ◽  
Age Groups ◽  
Selection Response ◽  
Sheep Flock ◽  
Breeding Scheme ◽  
Average Value ◽  
Group Breeding ◽  
Selection For ◽  
Progeny Group ◽  
Selection Differentials

ABSTRACTAn evaluation of the response to selection for prolificacy within a nucleus sheep flock of a commercial group-breeding scheme is presented. In 1979, the Romney Group Breeders formed a nucleus flock of 120 prolific ewes chosen from 12 contributing flocks. A control flock was established in 1982 from the same source. The analysis was conducted on the trait of litter size. Selection differentials are presented for each year of birth progeny group in both flocks. Expected selection response was calculated from selection differentials and was found to have an average value of 1·5% of parent mean litter size per year. Using least squares procedures the litter size performance of control and nucleus ewes of 2, 3 and 4 years of age was corrected for environmental effects. Realized response was estimated from the differences between corrected litter size means of control and nucleus flocks. Response in litter size was found to be significant within years and within ewe age groups (P < 0·05).

scholarly journals Mean-Based Breakpoint Selection on Circular Histogram

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Jiulun Fan ◽  
Jipeng Yang
Keyword(s):  
Selection Criteria ◽  
Color Image ◽  
Selection Criterion ◽  
Threshold Value ◽  
Simple Expression ◽  
Circular Data ◽  
Cumulative Distribution ◽  
Color Model ◽  
Hsi Color Model ◽  
Selection Of

Circular histogram represents the statistical distribution of circular data; the H component histogram of HSI color model is a typical example of the circular histogram. When using H component to segment color image, a feasible way is to transform the circular histogram into a linear histogram, and then, the mature gray image thresholding methods are used on the linear histogram to select the threshold value. Thus, the reasonable selection of the breakpoint on circular histogram to linearize the circular histogram is the key. In this paper, based on the angles mean on circular histogram and the line mean on linear histogram, a simple breakpoint selection criterion is proposed, and the suitable range of this method is analyzed. Compared with the existing breakpoint selection criteria based on Lorenz curve and cumulative distribution entropy, the proposed method has the advantages of simple expression and less calculation and does not depend on the direction of rotation.

scholarly journals Substitution Rates Under Stabilizing Selection

Genetics ◽  
1987 ◽  
Vol 116 (3) ◽  
pp. 479-486
Author(s):  
Alan Hastings
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Quantitative Traits ◽  
Strong Dependence ◽  
Phenotypic Selection ◽  
Analytical Models ◽  
Stabilizing Selection ◽  
Substitution Rates ◽  
Quantitative Characters ◽  
Selection For

ABSTRACT Allelic substitutions under stabilizing phenotypic selection on quantitative traits are studied in Monte Carlo simulations of 8 and 16 loci. The results are compared and contrasted to analytical models based on work of M. Kimura for two and "infinite" loci. Selection strengths of S = 4Nes approximately four (which correspond to reasonable strengths of selection for quantitative characters) can retard substitution rates tenfold relative to rates under neutrality. An important finding is a strong dependence of per locus substitution rates on the number of loci.

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