scholarly journals Genetic Variation and Response to Selection for Early Season Fruit Production in California Strawberry Seedling (Fragaria ×ananassa Duch.) Populations

2005 ◽  
Vol 130 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Douglas V. Shaw ◽  
Kirk D. Larson
Keyword(s):  
Genetic Variance ◽  
Total Yield ◽  
Selection Response ◽  
Fruit Production ◽  
Fragaria Ananassa ◽  
Early Season ◽  
Selection For ◽  
Selection Intensities ◽  
Opportunity For Selection ◽  
Selection Of

The genetic opportunity for selection of early fruiting strawberry cultivars was evaluated using seedling populations from the Univ. of California (UC) breeding program in three years. Narrow-sense heritabilities for early season yield and for the proportion of an individual's total yield expressed early were moderate (h2 = 0.24-0.53) and broad-sense heritabilities were slightly larger (H2 = 0.31-0.70), suggesting the presence of some nonadditive genetic variance for these traits. These two traits were genetically correlated with each other (rg = 0.78-0.98), but only early yield was consistently genetically correlated with seasonal yield (rg = 0.52-0.82). Selection was performed for each trait using an index on full-sib family means and individual phenotypic values in two of the three years, and predicted response was compared with that obtained using vegetatively propagated runner plants from selected genotypes in the subsequent fruiting season. Statistically significant (P < 0.05) selection response was obtained in one of two years for each trait, and combined analysis demonstrated highly significant (P < 0.01) response for both traits. However, realized response over all traits and years was just 27.3% of that predicted based on the estimated heritabilities and applied selection intensities. These results suggest that selection for early yield should be based at least in part on runner plant evaluations rather than exclusively on seedling performance.

scholarly journals Nursery Selection for High Early Fruit Yield in Subtropical Strawberries

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 548E-549
Author(s):  
P.J.S. Lopez ◽  
C.K. Chandler
Keyword(s):  
Total Yield ◽  
Fruit Production ◽  
Fruit Yield ◽  
Plant Production ◽  
First Year ◽  
Early Season ◽  
Factorial Mating ◽  
Selection For ◽  
Factorial Mating Design ◽  
Strawberry Cultivars

Development of new strawberry cultivars for winter fruit production in Florida entails growing of hybrid seedlings in a nursery in the summer of the first year for runner plant production. Two runner plants are taken from each seedling and planted in the fruiting field in the fall. An experiment was conducted to see if it is possible to predict which genotypes in the nursery will have the highest early season fruit yield. Seedlings from 24 families from a 6 × 4 factorial mating design were grown in a nursery. From each family, daughter plants of 20 seedlings with the highest vigor and 20 randomly picked seedlings were then evaluated in the fruiting field. Plants from selected (high-vigor) seedlings were more vigorous, but had fewer crowns and runners, than unselected plants. More inflorescences were counted in selected plants than in unselected plants during the second week of January. This could account for higher early yield (yield at the end of January) and total yield (yield at the end of March) in selected than in unselected plants.

ESTIMASI NILAI HERITABILITAS BOBOT IKAN MAS VARIETAS PUNTEN DALAM PROGRAM SELEKSI INDIVIDU

2016 ◽  
Vol 11 (3) ◽  
pp. 217
Author(s):  
Estu Nugroho ◽  
Budi Setyono ◽  
Mochammad Su’eb ◽  
Tri Heru Prihadi
Keyword(s):  
Body Weight ◽  
Selection Response ◽  
Base Population ◽  
Breeding Programs ◽  
Male And Female ◽  
Body Weight Trait ◽  
Population Selection ◽  
Selection For ◽  
Weight Trait ◽  
Selection Of

Program pemuliaan ikan mas varietas Punten dilakukan dengan seleksi individu terhadap karakter bobot ikan. Pembentukan populasi dasar untuk kegiatan seleksi dilakukan dengan memijahkan secara massal induk ikan mas yang terdiri atas 20 induk betina dan 21 induk jantan yang dikoleksi dari daerah Punten, Kepanjen (delapan betina dan enam jantan), Kediri (tujuh betina dan 12 jantan), Sragen (27 betina dan 10 jantan), dan Blitar (15 betina dan 11 jantan). Larva umur 10 hari dipelihara selama empat bulan. Selanjutnya dilakukan penjarangan sebesar 50% dan benih dipelihara selama 14 bulan untuk dilakukan seleksi dengan panduan hasil sampling 250 ekor individu setiap populasi. Seleksi terhadap calon induk dilakukan saat umur 18 bulan pada populasi jantan dan betina secara terpisah dengan memilih berdasarkan 10% bobot ikan yang terbaik. Calon induk yang terseleksi kemudian dipelihara hingga matang gonad, kemudian dipilih sebanyak 150 pasang dan dipijahkan secara massal. Didapatkan respons positif dari hasil seleksi berdasarkan bobot ikan, yaitu 49,89 g atau 3,66% (populasi ikan jantan) dan 168,47 g atau 11,43% (populasi ikan betina). Nilai heritabilitas untuk bobot ikan adalah 0,238 (jantan) dan 0,505 (betina).Punten carp breeding programs were carried out by individual selection for body weight trait. The base population for selection activities were conducted by mass breeding of parent consisted of 20 female and 21 male collected from area Punten, eight female and six male (Kepanjen), seven female and 12 male (Kediri), 27 female and 10 male (Sragen), 15 female and 11 male (Blitar). Larvae 10 days old reared for four moths. Then after spacing out 50% of total harvest, the offspring reared for 14 months for selection activity based on the sampling of 250 individual each population. Selection of broodstock candidates performed since 18 months age on male and female populations separately by selecting based on 10% of fish with best body weight. Candidates selected broodstocks were then maintained until mature. In oder to produce the next generation 150 pairs were sets and held for mass spawning. The results revealed that selection response were positive, 49.89 g (3.66%) for male and 168.47 (11.43%) for female. Heritability for body weight is 0.238 (male) and 0.505 (female).

scholarly journals EFFECTS OF POPULATION SIZE AND SELECTION INTENSITY ON SHORT-TERM RESPONSE TO SELECTION FOR POSTWEANING GAIN IN MICE

Genetics ◽  
1973 ◽  
Vol 73 (3) ◽  
pp. 513-530
Author(s):  
J P Hanrahan ◽  
E J Eisen ◽  
J E Legates
Keyword(s):  
Population Size ◽  
Selection Response ◽  
Selection Intensity ◽  
Realized Heritability ◽  
Family Selection ◽  
Effective Population ◽  
Population Sizes ◽  
Selection For ◽  
Selection Intensities ◽  
Term Response

ABSTRACT The effects of population size and selection intensity on the mean response was examined after 14 generations of within full-sib family selection for postweaning gain in mice. Population sizes of 1, 2, 4, 8 and 16 pair matings were each evaluated at selection intensities of 100% (control), 50% and 25% in a replicated experiment. Selection response per generation increased as selection intensity increased. Selection response and realized heritability tended to increase with increasing population size. Replicate variability in realized heritability was large at population sizes of 1, 2 and 4 pairs. Genetic drift was implicated as the primary factor causing the reduced response and lowered repeatability at the smaller population sizes. Lines with intended effective population sizes of 62 yielded larger selection responses per unit selection differential than lines with effective population sizes of 30 or less.

scholarly journals Optimum selection intensities in artificial selection programmes: an experimental evaluation

1977 ◽  
Vol 30 (2) ◽  
pp. 115-119 ◽  
Author(s):  
R. Frankham
Keyword(s):  
Experimental Evaluation ◽  
Selection Intensity ◽  
Effective Population ◽  
Term Selection ◽  
Optimum Selection ◽  
Selection For ◽  
Selection Intensities ◽  
Selection Of ◽  
Better Than

SUMMARYAn experimental evaluation of Robertson's (1970) theory concerning optimum intensities of selection for selection of varying durations has been carried out using published results from a long term selection study in Drosophila. Agreement of predicted rankings of treatments with expectations was excellent for low values of t/T (generations/total number scored) but poor for larger values of t/T. This was due to the 20% selection intensity treatments responding worse than expected and the 40% treatments relatively better than expected. Several possible reasons for the discrepancies exist but the most likely explanation is considered to be the greater reduction in effective population size due to selection in treatments with more intense selection.

scholarly journals Anticipated selection for intrapopulation breeding of passion fruit

2017 ◽  
Vol 39 (2) ◽  
pp. 143 ◽  
Author(s):  
Natan Ramos Cavalcante ◽  
Willian Krause ◽  
Alexandre Pio Viana ◽  
Celice Alexandre Silva ◽  
Keithi Karla Xavier Porto ◽  
...  
Keyword(s):  
Fruit Production ◽  
Passion Fruit ◽  
First Year ◽  
State University ◽  
Mato Grosso ◽  
Coincidence Index ◽  
Selection For ◽  
Fruit Mass ◽  
Selection Of ◽  
Production Characteristics

 The aim of this work was to verify the efficiency of the anticipated selection of superior plants in intrapopulation breeding of passion fruit. The experiment was conducted at the Mato Grosso State University experimental area. Eight populations were evaluated. Planting was carried out in August 2010 following the randomized blocks experimental design, with ten repeats and ten plants per plot. The production characteristics of mass and number of fruits were evaluated from data obtained from two cultivation periods, the first year and the full two-year cycle of culture. Estimates of genetic parameters indicate the possibility of selection gains. The accuracies of fruit production, fruit number and fruit mass characteristics had high magnitude, independent of the selection cycle. Coincidence index estimates were high for all characteristics. Based on the results, early selection (first year) was efficient and reduced the time of selection for the best plants and can be used for passion fruit breeding. 

Policy of selecting bulls to breed bulls

1987 ◽  
Vol 44 (1) ◽  
pp. 29-38 ◽  
Author(s):  
M. E. Goddard
Keyword(s):  
Dairy Cattle ◽  
Genetic Variance ◽  
Selection Response ◽  
Progeny Testing ◽  
Cattle Breeding ◽  
Sire Evaluation ◽  
Dairy Cattle Breeding ◽  
Breeding Programmes ◽  
Computer Simulation Program ◽  
Selection Of

ABSTRACTIn the breeding of dairy cattle the selection of bulls to breed young bulls for progeny testing is a crucial process. This paper compares several policies for making this selection based on the criteria-selection response, inbreeding depression, loss of genetic variance and variability of response. A number called the ‘effective number of new bulls to breed bulls selected each year’ (NBBe) is defined which is closely related to the last three of these criteria. Past studies of the design of dairy cattle breeding programmes have assumed that selection is within a group of bulls progeny tested in the same year (policy I). However, modern sire evaluation methods allow comparison of sires tested in different years. To evaluate the effect of selecting bulls to breed bulls from all available bulls (policy II) a computer simulation program was used. Policy II results in an increase in the response to selection but a substantial decrease in NBBe. When compared at the same NBBe, policy II results in a smaller selection response than policy I. A policy which allows the best bulls to be used for more than 1 year but which limits the maximum number of years for which they can be used, results in the best compromise. If bulls are to be used for several years there is little advantage to be gained from making more matings within each year to more high-rated bulls or to older, more reliably evaluated bulls.

scholarly journals INTERACTION BETWEEN NATURAL SELECTION FOR HETEROZYGOTES AND DIRECTIONAL SELECTION

Genetics ◽  
1974 ◽  
Vol 76 (1) ◽  
pp. 163-168
Author(s):  
Margrith Wehrli Verghese
Keyword(s):  
Natural Selection ◽  
First Generation ◽  
Genetic Variance ◽  
Selection Response ◽  
Directional Selection ◽  
Simple Function ◽  
Small Populations ◽  
Gene Frequencies ◽  
Selection For

ABSTRACT When directional selection for an additively inherited trait is opposed by natural selection favoring heterozygous genotypes a selection plateau may be reached where genetic variance is present. The amount of response when this plateau is reached is a simple function of the selection response in the first generation and the intensity of natural selection. When selection is practiced in small populations, the sizes of the initial equilibrium gene frequencies are at least as important as the intensity of natural selection in determining the probability of fixing desirable alleles.

scholarly journals Selection for Increased Budbreak in Apple

2003 ◽  
Vol 128 (3) ◽  
pp. 363-373 ◽  
Author(s):  
Iwan F. Labuschagné ◽  
J.H. Louw ◽  
Karin Schmidt ◽  
Annalene Sadie
Keyword(s):  
Genetic Variance ◽  
Screening Method ◽  
Selection Response ◽  
Significant Response ◽  
Correlated Response ◽  
Realized Heritability ◽  
Early Screening ◽  
Adult Trees ◽  
Selection For ◽  
Combined Selection

Significant response to selection for budbreak number (NB) based on data recorded on 1-year-old shoots of young apple (Malus sylvestris (L.) Mill var. domestica (Borkh.) Mansf.) seedlings (Expt. I) and branches from adult seedling trees (Expt. II) has been demonstrated in clonally propagated seedling trees. Between family variation for NB was low and masked by year × family interaction effects. Realized heritability for NB was estimated as 40% to 60%. Correlated response in uniformity and position of budbreak, and in the number and length of side shoots, was found. Association between the time of budbreak (TB) and NB, according to midparent and cross groupings, and according to the parental means, indicate a positive genetic correlation between these traits. Where data on adult trees were used as a measure of selection response and tested on young clonal trees, significant response and genetic variation was shown, confirming the presence of utilizable genetic variance and that this procedure may be successfully applied as an early screening method for increased budbreak in adult trees. Combined selection utilizing genetic variance between crosses as well as within crosses is proposed as the best procedure to increase the frequency of seedlings with increased budbreak and to improve adaptation to low winter chilling conditions.

scholarly journals Response of Egg Number to Selection of Different Genotypes of 24-bp Insertion-Deletion Locus in the Promoter of Prolactin Gene of Papua Local Chickens

2021 ◽  
pp. 18-26
Author(s):  
Muhammad Affan Mu'in ◽  
Sintje Lumatauw
Keyword(s):  
Selection Response ◽  
Breeding Value ◽  
Prolactin Gene ◽  
Egg Number ◽  
Selection For ◽  
Actual Response ◽  
Actual Selection ◽  
Selection Of ◽  
Selection Generation ◽  
Local Chickens

This study aims to estimate the response of the number of eggs produced up to 240 days of age (EN240) to the selection of Papua local chickens (PLC) with different genotypes from the 24-bp Indel cPRLp locus. A total of 68 PLCs were taken randomly from several breeders in Manokwari as the basic population for selection (G0). Genotype identification of the 24-bp Indel cPRLp locus was performed G0. Based on the distribution of these genotypes, mating pairs were randomly formed G0-II, G0-DD and G0-ID to produce G1-II, G1-DD, and G1-Control (G0-ID offspring). Heritability of EN240 in G1-II and G1-DD populations were estimated in full-sib (single pairs mating). Individual selection based on breeding value EN240 was carried out on G1-II (♀) and G1-DD (♀) to form the selection generation (GS): GS-II (♀) and GS-DD (♀). Selection was also carried out on G1-II (♂) and G1-DD (♂) based on body weight at 240 days (BW240) to become selected GS-II (♀) and GS-DD (♀) mating partners. GS-Control was also formed through 25% random sampling from G1-Control (♂ and ♀). GS mating resulted in the second generation (G2): G2-II, G2-DD, and G2-Control. Age at first laying (AFL), EN240, and mean egg weight (EWA) in hens of G1, GS, and G2 were recorded. Response to selection for EN240 was calculated by two methods predicted selection response (Rp) and actual selection response (Rr). Both methods of calculation yield positive and high values. In actual response (Rr), PLC in II genotypes group are more responsive to the selection treatment than DD genotype group. Selection increase EN240 impact accelerate of AFL and lower the EWA, because of their negative genetic correlation.

scholarly journals Response in Genotypic and Breeding Value to a Single Generation of Divergent Selection for Fresh Fruit Color in Strawberry

1995 ◽  
Vol 120 (2) ◽  
pp. 270-273 ◽  
Author(s):  
Douglas V. Shaw ◽  
Erik J. Sacks
Keyword(s):  
Genetic Variance ◽  
Breeding Population ◽  
Selection Response ◽  
Fruit Color ◽  
Divergent Selection ◽  
Fresh Fruit ◽  
Breeding Value ◽  
Genetic Variances ◽  
Selection For ◽  
Genotypic Selection

Four sets of selected strawberry (Fragaria ×ananassa Duch.) genotypes were generated from within a single breeding population to evaluate the correspondence between predicted and realized selection response for fresh fruit color traits. Genotypes were selected for extreme phenotypes, dark or light, of either internal or external color value (CIELAB L*). Genotypic selection response was evaluated empirically by scoring fruit from the clonal derivatives of these selected genotypes, and response for breeding value was estimated by scoring the offspring of crosses performed among a subset of the genotypes within each selected set. Realized selection response was slightly larger than predicted for internal and external L* when calculated for selected genotypes. Also, more than half of the selected genotypes had genotypic values for L* outside the range of the original parents, providing evidence for transgressive segregation. Realized selection response for breeding value in exterior and interior color was slightly less than predicted. Compared in a different way, genotypic selection response for external color was significantly greater than selection response for breeding value, whereas genotypic and breeding value responses did not differ for internal color. These observations suggest the presence of some nonadditive genetic variance for external color but support the conclusion that the heritabilities predicted previously were reasonably accurate. Estimates of variance components within each of the offspring populations demonstrated that genetic variances were modified substantially by one generation of selection. Selection for dark fruit color reduced genetic variance to nonsignificant levels, with internal color more affected than external color. The total genetic variances within both of the offspring populations from parents selected for light color were changed little by one generation of selection, but substantial dominance variance was detected that had not been found in the original population. The rapid response to selection and large changes in the distribution of genetic variances may indicate the presence of a few genes with comparatively large effect in strawberry color expression. Additional divergent selection response can be expected, but primarily in the direction of light fruit color.

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