scholarly journals Multistage selection for genetic gain by orthogonal transformation.

Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 963-974 ◽  
Author(s):  
S Z Xu ◽  
W M Muir
Keyword(s):  
Selection Index ◽  
Orthogonal Transformation ◽  
Cost Savings ◽  
Breeding Value ◽  
Economic Returns ◽  
Selection Scheme ◽  
Genetic Gains ◽  
Independent Culling ◽  
Total Proportion ◽  
Multistage Selection

Abstract An exact transformed culling method for any number of traits or stages of selection with explicit solution for multistage selection is described in this paper. This procedure does not need numerical integration and is suitable for obtaining either desired genetic gains for a variable proportion selected or optimum aggregate breeding value for a fixed total proportion selected. The procedure has similar properties to multistage selection index and, as such, genetic gains from use of the procedure may exceed ordinary independent culling level selection. The relative efficiencies of transformed to conventional independent culling ranged from 87% to over 300%. These results suggest that for most situations one can chose a multistage selection scheme, either conventional or transformed culling, which will have an efficiency close to that of selection index. After considering cost savings associated with multistage selection, there are many situations in which economic returns from use of independent culling, either conventional or transformed, will exceed that of selection index.

scholarly journals Prediction of genetic gains for breeding objective traits and designing selection schemes for Washera and Gumuz indigenous sheep

2021 ◽  
Vol 4 (1) ◽  
pp. 1-13
Author(s):  
Sisay Asmare ◽  
Sisay Asmare ◽  
Kefyalew Alemayehu ◽  
Solomon Abegaz K. ◽  
Aynalem Haile ◽  
...  
Keyword(s):  
Litter Size ◽  
Selection Index ◽  
Genetic Response ◽  
Breeding Scheme ◽  
Selection Scheme ◽  
Genetic Gains ◽  
Washera Sheep ◽  
Indigenous Sheep ◽  
Breeding Objective ◽  
One Year

In Ethiopia,there are 32.85 millions of sheep,more than 99 % of which are indigenous.However,the productivity of local sheep under traditional production system is low with high mortality of sheep.There are two ways of improving performance of sheep and goats,namely improving the enviroment of animals and/or improving there genetic potential.The aim of this study was to predict genetic gains of breedingobjective traits and select the best sheep selection scheme for Gumuz andWashera sheep. Body size(six month weight and yearling weight) and litter size were breeding objective traits identified by own flock animal ranking experiment and personal interview. Deterministic approach of ZPLAN computor program is used for modeling input parametres of Gumuz and Washera sheep and simulating breeding plans using gene flow method and selection index procedures. One-tier cooperative sheep breeding scheme were proposed whereby ram exchange between and within villages is the main means of genetic dissimination. Genetic gains predicted for six month weight of Gumuz and Washera sheep were 0.43 and 0.55 kg,respectively. Genetic gains predicted for yearling weight of Gumuz and Washera sheep were 0.55 and 0.60 kg,respectively. Genetic gains predicted for litter  size of Gumuz and Washera sheep were 0.08 and 0.09 lambs,respectively. The lower rate of inbreeding, the higher monetary genetic gain for aggregate genotype,higher return to investmnet and higher profit/ewe/year were quality measures of breeding program considered to prefer scheme 4 for both Gumuz and Washera sheep.Hence,for both Gumuz and Washera sheep populations a sheep selection scheme designed with 15 % selection proportion and one year ram use for breeding was recommended. Special emphasis need to be given to yearling weight with higher predicted genetic response and higher percentage return to investment.

scholarly journals A further examination of the relative efficiency of three methods of selection for genetic gains under less-restricted conditions

1961 ◽  
Vol 2 (1) ◽  
pp. 106-121 ◽  
Author(s):  
S. S. Y. Young
Keyword(s):  
Relative Efficiency ◽  
Selection Index ◽  
Phenotypic Correlation ◽  
Relative Importance ◽  
Selection Intensity ◽  
Genetic Gains ◽  
Equal Importance ◽  
Independent Culling ◽  
Correlated Characters ◽  
Efficiency Of Selection

The relative efficiency of three methods of selection (index, independent culling levels and tandem) is compared in terms of genetic gains in economic units. The comparison covers cases where variances, heritabilities and economic weights are unequal, while the case of two correlated characters is also examined. Various factors may influence the relative efficiency, including selection intensity, the number of traits under selection, the relative importance of those traits (in terms of a factor λ, which is the product of economic weight, heritability and phenotypic standard deviation), and the correlations between them.The conclusions are:(i) In all circumstances the index is never less efficient than independent culling levels, though in some cases it is no more efficient. Independent culling is, in turn, never less, but in some cases no more efficient than tandem selection.(ii) The superiority of the index over other methods increases with an increasing number of traits under selection, but decreases with increasing differences in relative importance, its superiority being at a maximum when the traits are of equal importance. The superiority of the index over independent culling levels decreases with increasing selection intensity, but its superiority over tandem selection is independent of intensity.(iii) The superiority of independent culling over tandem selection increases with increasing selection intensity or an increasing number of traits under selection, but decreases with increasing differences in relative importance.(iv) The relative efficiency of the index over other methods is much affected by the phenotypic correlation between traits when the traits are of equal importance, the relative efficiency of the index being higher when the phenotypic correlation is low or negative. The effect of genetic correlation is only apparent when the traits are of unequal importance and its influence on relative efficiency changes with changes in other parameters.(v) The relative efficiency of selection methods may be changed by their use for special purposes.

scholarly journals Optimal breeding-value prediction using a Sparse Selection Index

Genetics ◽  
2021 ◽  
Author(s):  
Marco Lopez-Cruz ◽  
Gustavo de los Campos
Keyword(s):  
Sample Size ◽  
Dna Sequences ◽  
Genomic Prediction ◽  
Prediction Accuracy ◽  
Regularization Parameter ◽  
Selection Index ◽  
Prediction Method ◽  
Training Data ◽  
Breeding Value ◽  
Data Set

Abstract Genomic prediction uses DNA sequences and phenotypes to predict genetic values. In homogeneous populations, theory indicates that the accuracy of genomic prediction increases with sample size. However, differences in allele frequencies and in linkage disequilibrium patterns can lead to heterogeneity in SNP effects. In this context, calibrating genomic predictions using a large, potentially heterogeneous, training data set may not lead to optimal prediction accuracy. Some studies tried to address this sample size/homogeneity trade-off using training set optimization algorithms; however, this approach assumes that a single training data set is optimum for all individuals in the prediction set. Here, we propose an approach that identifies, for each individual in the prediction set, a subset from the training data (i.e., a set of support points) from which predictions are derived. The methodology that we propose is a Sparse Selection Index (SSI) that integrates Selection Index methodology with sparsity-inducing techniques commonly used for high-dimensional regression. The sparsity of the resulting index is controlled by a regularization parameter (λ); the G-BLUP (the prediction method most commonly used in plant and animal breeding) appears as a special case which happens when λ = 0. In this study, we present the methodology and demonstrate (using two wheat data sets with phenotypes collected in ten different environments) that the SSI can achieve significant (anywhere between 5-10%) gains in prediction accuracy relative to the G-BLUP.

scholarly journals Genetic gains under three methods of selection

1962 ◽  
Vol 3 (3) ◽  
pp. 417-423 ◽  
Author(s):  
D. J. Finney
Keyword(s):  
Linear Function ◽  
Genetic Gain ◽  
Index Selection ◽  
Genetic Gains ◽  
Independent Culling

Results obtained by Young for the expectation of genetic gain in an arbitrary linear function of several traits under selection by independent culling levels, under tandem selection, and under index selection have been obtained in slightly more general form and their dependence on basic genetic and phenotypic parameters exhibited. A warning is given about the effects of selection in modifying the distribution of traits; when the distribution has become appreciably non-normal, any calculation of genetic gains from formulae based on normality will tend to overestimation.

scholarly journals MoBPSweb: A web-based framework to simulate and compare breeding programs

2020 ◽  
Author(s):  
T. Pook ◽  
L. Büttgen ◽  
A. Ganesan ◽  
N.T. Ha ◽  
H. Simianer
Keyword(s):  
Selection Index ◽  
Relevant Information ◽  
Simulation Software ◽  
Breeding Program ◽  
Breeding Value ◽  
Long Term Effects ◽  
General Applicability ◽  
Breeding Programs ◽  
Web Based ◽  
Value Estimation

ABSTRACTSelective breeding is a continued element of both crop and livestock breeding since early prehistory. In this work, we are proposing a new web-based simulation framework (“MoBPSweb”) that is combining a unified language to describe breeding programs with the simulation software MoBPS, standing for ‘Modular Breeding Program Simulator’. Thereby, MoBPSweb is providing a flexible environment to enter, simulate, evaluate and compare breeding programs. Inputs can be provided via modules ranging from a Vis.js-based flash environment for “drawing” the breeding program to a variety of modules to provide phenotype information, economic parameters and other relevant information. Similarly, results of the simulation study can be extracted and compared to other scenarios via output modules (e.g. observed phenotypes, accuracy of breeding value estimation, inbreeding rates). Usability of the framework is showcased along a toy example of a dairy cattle breeding program on farm level, with comparing scenarios differing in implemented breeding value estimation, selection index and selection intensity being considered. Comparisons are made considering both short and long-term effects of the different scenarios in terms of genomic gains, rates of inbreeding and the accuracy of the breeding value estimation. Lastly, general applicability of the MoBPSweb framework and the general potential for simulation studies for genetics and in particular in breeding are discussed.

scholarly journals Application of selection index method to combine two generations of estimated breeding value in pigs.

1989 ◽  
Vol 26 (3) ◽  
pp. 188-196
Author(s):  
Hiroshi TAKAHASHI ◽  
Takashige SUGIMOTO ◽  
Akio NIBE ◽  
Allan SCHINCKEL ◽  
Yasuo AMEMIYA
Keyword(s):  
Selection Index ◽  
Breeding Value ◽  
Index Method ◽  
Two Generations ◽  
Estimated Breeding Value

Experimental comparison of restricted selection index and restricted independent culling levels in Tribolium castaneum

Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 91-96 ◽  
Author(s):  
J. L. Campo ◽  
B. Villanueva
Keyword(s):  
Tribolium Castaneum ◽  
Selection Index ◽  
Egg Laying ◽  
Experimental Comparison ◽  
Pupal Weight ◽  
Selection Methods ◽  
Adult Weight ◽  
Antagonistic Selection ◽  
Independent Culling ◽  
Restricted Selection

A selection index (I) method was compared with independent culling levels (N), with a restriction in the selection program, using two replicated single generation experiments in Tribolium castaneum, which are considered forms of antagonistic selection. The first experiment was designed to increase adult weight without changing pupal weight, while the second experiment was intended to improve egg laying without changing adult weight. In both experiments the genetic correlation between the traits involved were positive but were higher in experiment 1 than in experiment 2. The proportion of selection was 10%. In experiment 1, the effect of restriction was as expected in both lines since the changes in pupal weight were not significant. Adult weight change was positive for the I line and negative for the N line, showing that the index was a superior method to improve adult weight. In experiment 2, the effect of restriction was also as expected in both lines and changes in adult weight were not significant. Egg laying changed positively in both lines. Therefore, both selection methods were similar in this experiment, even though egg laying change was higher in the I than the N line. Key words: restricted index, restricted culling levels, antagonistic selection, Tribolium.

scholarly journals The assessment of genetic potential in performance tested gilts by means of selection indexes method

Genetika ◽  
2014 ◽  
Vol 46 (1) ◽  
pp. 95-104 ◽  
Author(s):  
Mladen Popovac ◽  
Milica Petrovic ◽  
Dragan Radojkovic ◽  
Dragan Stanojevic ◽  
Aleksandar Miletic ◽  
...  
Keyword(s):  
Body Mass ◽  
Significant Variation ◽  
Selection Index ◽  
Research Paper ◽  
Backfat Thickness ◽  
Breeding Value ◽  
Birth Season ◽  
Genetic Potential ◽  
Selection Indexes ◽  
The One

The objective of this research paper was to make an assessment of breeding value of performance tested gilts of Swedish Landrace and F1 crossbreds of Swedish Landrace and Great Yorkshire by the method of selection index. The traits on whose basis the breeding value was estimated were: daily liveweight gain, average backfat thickness measured at two sites and carcass meat percentage. These traits were corrected for body mass of 100kg by the method of base indexes and the following average values were determined: corrected daily liveweight gain (KZDP) 408.93g/day, corrected average backfat thickness measured at two sites (KSL) 9.77mm and corrected carcass meat percentage (KPM) 61.08%. Studying the effect of genotype, year and birth season of gilts a statistically significant variation (P>0.05) of these traits provoked by the mentioned factors was not determined while the gilts` sire statistically highly significantly (P<0.001) influenced all studied traits. Heritability coefficients were: h2= 0.255 for KZDP, h2= 0.356 for KSL and h2 = 0.349 for KPM. The four selection index equations were constructed among which as the most optimal was chosen the one which includes all three traits (KZDP, KSL and KPM) and whose coefficient of the correlation of selection index and aggregate genotype was rIAG = 0.594.

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