Genetic gain with desired status number in breeding programs: a study on selection effects

1998 ◽  
Vol 28 (12) ◽  
pp. 1861-1869 ◽  
Author(s):  
R -P Wei ◽  
C R Hansen ◽  
N K Dhir ◽  
F C Yeh
Keyword(s):  
Genetic Gain ◽  
Breeding Population ◽  
Breeding Value ◽  
Index Selection ◽  
Selection Methods ◽  
Family Selection ◽  
Breeding Populations ◽  
High Heritability ◽  
Status Number ◽  
Restricted Selection

Genetic gain and average coancestry or status number was investigated for five selection methods: penalty index selection (PIS), family index selection (FIS), combined between-family and within-family selection (CBW), restricted individual selection (RIS), and combined index selection (RCS). PIS was a function of an individual's breeding value and family contributions, modelled as a stepwise procedure to select superior individuals one by one. A penalty would indicate the need to have low average coancestry or large status number. Breeding populations of unrelated families were investigated by Monte Carlo simulation to examine the genetic response of the five selection methods at a restricted selection intensity and average coancestry. PIS attained the greatest genetic gain, except at the selection limits of maximum genetic gain and minimum average coancestry where PIS might be identical to the other selection methods. FIS and RCS well approximated PIS at high average coancestry. RIS was similar to RCS when the heritability was high, particularly at low average coancestry. CBW attained the least genetic gain among the selection methods. For all selections, high heritability would contribute to a greater genetic gain and status number or low average coancestry. PIS was applied to a practical breeding program in Alberta that included several subpopulations. The results suggested that the selection efficiency for balancing genetic gain and average coancestry would increase when deploying a subpopulation strategy for breeding population management.

Expected gain and status number following restricted individual and combined-index selection

Genome ◽  
1997 ◽  
Vol 40 (1) ◽  
pp. 1-8 ◽  
Author(s):  
R.-P. Wei ◽  
F. C. Yeh ◽  
D. Lindgren
Keyword(s):  
Genetic Gain ◽  
Real Life ◽  
Selection Criterion ◽  
Breeding Value ◽  
Index Selection ◽  
Expected Gain ◽  
Status Number ◽  
Efficiency Of Selection ◽  
Number Of Individuals ◽  
Restricted Selection

Imposition of restrictions on number of individuals selected from a family and number of families from which superior individuals are selected could markedly alter the consequences of individual and combined-index selection. Predicted genetic gain and diversity measured as status number following selection were studied to draw general conclusions. Selection and its prediction were applied to two sets of real-life data. Theoretical prediction gave results close to those from factual selection. Gain and status number varied with initial family number and size, sib type, heritability, selection proportion, restriction type and intensity, and selection criteria. Proper restriction on the number of individuals selected can control the reduction of status number to an acceptable level, particularly when breeding values are used as the selection criterion. Restriction on the number of families selected would effectively improve the gain efficiency of selection based on phenotypic values. Choosing combinations of both restrictions might produce higher gain without the loss of status number. Given constant population size, family number should be large enough to ensure that restricted selection will yield higher gain and status number.Key words: restricted selection, phenotype, breeding value, genetic gain, effective size.

scholarly journals Stepwise Penalty Index Selection from Populations with a Hierarchical Structure

2006 ◽  
Vol 55 (1-6) ◽  
pp. 62-70 ◽  
Author(s):  
Run-Peng Wei ◽  
D. Lindgren
Keyword(s):  
Hierarchical Structure ◽  
Breeding Value ◽  
Index Selection ◽  
Selection Methods ◽  
Family Selection ◽  
Stepwise Procedure ◽  
Extreme Solutions ◽  
The Relationship ◽  
Family Contribution ◽  
Selection Of

Abstract By adding a penalty to a candidate’s breeding value for its relationship with the selected individuals, two indexes were constructed as criteria for stepwise selection of superior individuals from populations with a hierarchical structure. The relationship was expressed in terms of either family contribution or group coancestry. One of the indexes was derived from an optimal selection model. A stepwise procedure that screened superior individuals one by one was introduced to make selection based on these indexes possible. Two penalty selection methods exclusively maximized gain at given coancestry. Both methods produced all identical solutions in most of the populations simulated, and were nearly equivalent in the remaining populations, particularly when heritability was high and the population structure was simple. A better balance between gain and coancestry following penalty index selection can be obtained by avoiding the two extreme solutions: combined- index and within-family selection, and using simple mating designs rather than complex ones.

scholarly journals Genetic Gain and Diversity under Different Selection Methods in a Breeding Seed Orchard of Quercus serrata

2007 ◽  
Vol 56 (1-6) ◽  
pp. 277-281 ◽  
Author(s):  
K. S. Kang ◽  
B. H. Cheon ◽  
S. U. Han ◽  
C. S. Kim ◽  
W. Y. Choi
Keyword(s):  
Genetic Gain ◽  
Gene Diversity ◽  
Seed Orchard ◽  
Selection Method ◽  
Quercus Serrata ◽  
Selection Intensity ◽  
Individual Selection ◽  
Selection Methods ◽  
Family Selection ◽  
Status Number

Abstract Genetic gain and diversity were estimated in a 13- year old Quercus serrata breeding seed orchard under three selection (rouging) methods. The selections were based on individual selection, family selection, and family plus within family selection. Genetic gain was for stem volume and gene diversity was estimated by status number concept. Both estimated genetic gain and gene diversity were compared to those before selection and among selection scenarios. Estimated genetic gain for tree volume ranged from 4.0% to 9.1% for three selection methods under 50% selection intensity. Individual selection was better than family selection for retaining higher genetic gain and status number. Family plus within family selection was the best selection method, while individual selection was more efficient at the strong selection intensity. An optimal point, which maximized gain and diversity, was occurred at 50% selection intensity that would be applied for genetic thinning in the breeding seed orchard of Quercus serrata. The effect of genetic relatedness among families and possible pollen contamination on both genetic gain and gene diversity, although were not studied but their impact, are discussed. The selection method and intensity level applied should be chosen after careful consideration of the impacts on both genetic gain and diversity for seeds produced from the seed orchard.

The impact of spatial heterogeneity on selection: a case study on Pinus pinaster breeding seedling orchards

2008 ◽  
Vol 38 (1) ◽  
pp. 114-124 ◽  
Author(s):  
Rafael Zas
Keyword(s):  
Spatial Autocorrelation ◽  
Spatial Patterns ◽  
Genetic Gain ◽  
Pinus Pinaster ◽  
Spatial Models ◽  
Selection Methods ◽  
Family Selection ◽  
The Impact

Although failure to account for spatial autocorrelation has been dramatic in some forest progeny trials, little attention has been paid to how this issue may affect selections within the trials. The effects of spatial autocorrelation of height growth on the estimation of genetic gain and on the spatial distribution of the selected trees were studied in four Pinus pinaster Ait. progeny trials that were rogued using different selection methods and intensities. When selections are based on unadjusted original values, selected trees tend to be located in the best microsites and are unlikely to be the most genetically superior. This resulted in a loss of genetic gain that varied between 10% and 20% and sometimes exceeded 30%. Differences in the loss of gain among different selection methods and intensities were minor and followed no clear pattern. Selecting on the basis of a conventional model resulted in spatial patterns of the retained trees that were clearly aggregated in all cases. However, selections based on spatially adjusted data resulted in random spatial patterns, except with family selection because of the use of multiple-tree plots. Because clumping of the retained trees may seriously affect the quantity and quality of the seed crop, breeders are strongly encouraged to use appropriate spatial models for roguing breeding seedling orchards.

Stratified sublining: a new option for structuring breeding populations

2000 ◽  
Vol 30 (4) ◽  
pp. 596-604 ◽  
Author(s):  
Seppo Ruotsalainen ◽  
Dag Lindgren
Keyword(s):  
Genetic Gain ◽  
Breeding Population ◽  
Random Allocation ◽  
Genetic Quality ◽  
Seed Orchards ◽  
Breeding Values ◽  
Breeding Populations ◽  
Genetic Value ◽  
Interesting Alternative

When structuring a breeding population into sublines, the conventional approach is to assign parents to sublines randomly, so that each subline has approximately the same genetic value. By using deterministic infinitesimal model we study an alternative, stratified sublining system, where sublines are initially formed by positive assortative grouping of parents according to their breeding values. Stratified and random allocation to sublines are compared by evaluating the genetic quality of the seed orchards that each approach can provide. The seed orchards were established by selecting first the best individual from each subline and then a given best proportion from them. The greater among-subline variance in stratified sublining led to higher genetic gain in resulting seed orchards than did random sublining. For the case studied, stratified sublining gave considerably more genetic gain than random sublining, over 15% more, making it an interesting alternative that deserves further consideration and study.

Balanced forest tree improvement can be enhanced by selecting among many parents but maintaining balance among grandparents

2008 ◽  
Vol 38 (11) ◽  
pp. 2797-2803 ◽  
Author(s):  
Dag Lindgren ◽  
Darius Danusevičius ◽  
Ola Rosvall
Keyword(s):  
Genetic Gain ◽  
Phenotypic Selection ◽  
Tree Breeding ◽  
Breeding Population ◽  
Forest Tree ◽  
Selection Strategy ◽  
Family Selection ◽  
Parent Selection ◽  
Tree Breeding Program ◽  
Balanced Tree

A model for a balanced tree breeding program that considers genetic gain and cost was used to assess the benefits of increasing the breeding population to allow for a component of among-parent selection while maintaining an equal contribution among grandparents, rather than relaying on within-family selection with an equal parental representation. The scenario used in this study had characteristics similar to those of the phenotypic selection strategy for Scots pine ( Pinus sylvestris L.) in Sweden. The results showed that investments in a greater number of parents and families to allow for among-parent selection resulted in a markedly higher genetic gain. The among-parent selection component increased the genetic gain by as much as 70% in a scenario with a high budget and no family creation costs and by as much as 20% in a scenario with a low budget and high family creation costs.

scholarly journals Prediction of genetic gain in Ficus variegata progeny trial based on breeding value

2019 ◽  
Vol 20 (10) ◽  
Author(s):  
LILIEK HARYJANTO ◽  
Prastyono Prastyono ◽  
Yayan Hadiyan ◽  
Mudji Susanto
Keyword(s):  
Genetic Correlation ◽  
Genetic Gain ◽  
Genetic Improvement ◽  
Block Design ◽  
Breeding Value ◽  
Narrow Sense ◽  
Family Selection ◽  
Progeny Trial ◽  
Individual Value ◽  
Estimation Of Variance

Abstract. Haryjanto L, Prastyono, Hadiyan Y, Susanto M. 2019. Prediction of genetic gain in Ficus variegata progeny trial based on breeding value. Biodiversitas 20: 2994-2999. Prediction of genetic gain in Ficus variegata Blume progeny trial based on breeding values. The aim of this study was to estimate the breeding value based on components variance and genetic gain prediction of Ficus variegata Blume using REML/BLUP. A total of 17 families of Ficus variegata Blume were evaluated at three years after planting at progeny trial in Mangunan, Bantul, Yogyakarta laid out in Randomized Completely Block Design (RCBD). Estimation of variance family (height and diameter) were ± 5% of total variance. Narrow-sense individual heritability was moderate (0.27 and 0.21 respectively) indicated promising genetic improvement. Strong genetic correlation of height and diameter (rG=0.9) indicated that improving a trait will improving others. BLUP analysis for diameter trait showed that the best individual value from best family selection was appropriated with restriction 10 family and 5 individual per family and genetic gain prediction was 15.83% gave acceptable rate of inbreeding 2% per generation.

scholarly journals Comparison of Phenotype and Combined Index Selection at Optimal Breeding Population Size Considering Gain and Gene Diversity

2006 ◽  
Vol 55 (1-6) ◽  
pp. 13-19 ◽  
Author(s):  
H. Li ◽  
D. Lindgren
Keyword(s):  
Population Size ◽  
Gene Diversity ◽  
Phenotypic Selection ◽  
Breeding Population ◽  
Individual Performance ◽  
Breeding Value ◽  
Index Selection ◽  
Efficient Generation ◽  
The Difference ◽  
The Individual

Abstract A breeding program was simulated in this study. Two alternative ways of selecting the breeding population for the following generation was compared. Phenotypic selection, which means to select just on the individual performance, and combined index selection, which means selection on predicted breeding value for each individual obtained by weighting family average and individual phenotype, were compared. The plant number (testing resource) and gene diversity (status number, Ns) were kept constant, but the breeding population size was variable and chosen for maximizing gain for the particular breeding scenario. At low and medium heritability phenotypic selection was inferior to combined index selection. Only when heritability was high phenotypic selection was as efficient (generation 1) as or more efficient (generation 5) than combined index selection. This contrasts to earlier studies done under constant breeding population size, where selection methods appeared similar. The advantage in gain of combined index selection is usually at a larger breeding population size. At limited heritability and breeding population size the difference is considerable. When breeding population size was kept rather small (<100), and the heritability limited, combined index selection can result in slightly higher gain than phenotypic selection at the same gene diversity, but this was at the cost of a much larger breeding population. Phenotypic selection and combined index selection appears as rather similar for many cases in this simple model used in this study. Considering other advantages with phenotypic selection, it may often be regarded as a competitive alternative.

scholarly journals Maintaining genetic variation in breeding populations of Radiata pine in New Zealand

2019 ◽  
Vol 68 (1) ◽  
pp. 9-13
Author(s):  
C.J.A Shelbourne
Keyword(s):  
Genetic Variation ◽  
New Zealand ◽  
Stochastic Simulation ◽  
Radiata Pine ◽  
Breeding Population ◽  
Management Plan ◽  
Family Selection ◽  
Breeding Populations ◽  
The Future ◽  
Made In

Abstract Advanced generation selection (AS) for the future breeding population (BP), becam a focus of tree breeders‘ thinking in the mid 1970s., particularly with Pinus radiata in New Zealand (NZ). Multitrait selection among families was generally recommen­ded, but this reduced genetic variation in the future breeding population. From Shaw and Hood‘s (1985) stochastic simulation, later confirmed by Rosvall, Lindgren and Mullin‘s (1998) stochastic simulation on Norway spruce, it was realised that selecting within families rather than among families of a new breeding population avoided any reduction of genetic variation in the BP. Heritabilities were low for seedling within-family selection but clonal replication within families should strongly increase heritabilities. Gains from cloned versus seedling populations of equal numbers of plants were also deterministically simulated (Shelbourne et al. 2007), and balanced (within-family) selec­tion gains from the cloned populations were all higher than seedling equivalents at heritabilities of 0.5 and under. The late P.A. Jefferson‘s (2016) Breeding Management Plan (which will be soon superceded) contains a re description of New Zealand (NZ) radiata pine breeding. Selections were made in crosses from the earlier program and OP see and scion mate­rial were collected from all 360 selections. OP family tests of selections have been planted at 11 sites in NZ and 7 in New South Wales and Tasmania, and scions of their female parents have all been grafted at an archive. Crosses made in the archive are being cloned and the programme was committed to within-family selection to retain genetic variance for the future closed breeding population. Clonally-replicated testing paired with within-family selection is the solution for balancing long-term gain and diversity in BP and PP.

A comparison of individual, family, and index selection methods in Tribolium castaneum

1986 ◽  
Vol 28 (2) ◽  
pp. 301-305 ◽  
Author(s):  
D. L. McLeod ◽  
G. W. Friars
Keyword(s):  
Tribolium Castaneum ◽  
Genetic Gain ◽  
Index Selection ◽  
Selection Methods ◽  
Combined Method ◽  
Single Generation ◽  
The Family ◽  
Individual Family ◽  
Upward Direction ◽  
Sib Families

Seven replicates of single-generation selection were used to compare genetic gain in Tribolium castaneum, using methods based on information from individuals, full-sib families, or both. Realized responses in pupa weight were greater when selection was applied in the downward as opposed to the upward direction. Although the contrasts were not all significant, the observed response in the upward direction agreed with theoretical expectations where the ranking of methods was combined first, family second, and individual last. In the downward direction, response based on the family method was below expectations, and the combined method yielded results close to those for selection based on individuals.Key words: selection methods, Tribolium, asymmetric response.

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