scholarly journals Selection for Papaya Resistance to Multiple Diseases in a Base Population of Recurrent Selection

2021 ◽  
Author(s):  
RAMON de MORAES ◽  
Marcelo Vivas ◽  
Derivaldo Pureza da Cruz ◽  
Renato Santa Catarina ◽  
Rafael Nunes de Almeida ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Gene Pool ◽  
Crop Production ◽  
Recurrent Selection ◽  
Selection Index ◽  
Black Spot ◽  
Direct Selection ◽  
Production Traits ◽  
Base Population ◽  
Combined Selection

Abstract Papaya has a narrow genetic base concerning disease resistance, with few genetically distinct cultivars for planting in the world. Losses in crop production caused by fungal and viral diseases, added to the absence of resistant cultivars available to producers, have reduced the competitiveness of crops. Therefore, this study aimed to estimate the direct and combined genetic gains in the base population of the recurrent papaya selection and to indicate promising individuals for resistance to phoma spot and black spot. The population used in this study originated from the crossing of dioecious, female individuals and holders of a gene pool for resistance to phoma spot and black spot. These were crossed with elite individuals with a gene pool for production traits and fruit quality. The experiment was carried out without an experimental design, containing one plant per plot. Three measurements were taken on 255 individuals for five traits of disease resistance, being: four associated with black spot (incidence and severity on the leaf and fruit) and one associated with phoma spot (severity on the leaf). With the observations obtained, the REML/BLUP procedure was performed to estimate the temporary and permanent environmental effects. Such values were used to know the genetic parameters of the population and to elaborate a combined selection index, as well as to compare the gains with the direct selection. The results indicate low repeatability for the traits and that the gains obtained from the use of the combined selection index better rank the genotypes in comparison to the gains obtained by direct selection.

Use of productive data to predict length of productive life in Iranian Holstein cattle

2005 ◽  
Vol 2005 ◽  
pp. 126-126
Author(s):  
A. Abdolmohammadi ◽  
M. Moradi Shahrebabak ◽  
S. R. M. Ashtiani
Keyword(s):  
Milk Production ◽  
Genetic Parameters ◽  
Selection Index ◽  
Direct Selection ◽  
Holstein Cattle ◽  
Production Traits ◽  
Milk Production Traits ◽  
Direct Evaluation ◽  
Productive Life ◽  
Selection Of

Improvement of longevity by direct selection of sires based on theirs daughters’ longevity measures is impractical because of a low heritability and generation intervals prolonged by waiting until all cows complete their productive life. As an alternative to direct evaluation of sires for longevity is indirect prediction from genetically correlated production traits measures in the first lactation. The objectives this study were 1) to estimate genetic parameters of longevity and production traits 2) to examine relationships between longevity and first lactation milk production traits and 3) to determine selection index for sires’ longevity based on production traits.

scholarly journals Associations among production and physicochemicalquality fruit traits in Passion fruit populations subjected to three cycles of intrapopulation recurrent selection

2018 ◽  
Vol 40 (5) ◽  
Author(s):  
Natan Ramos Cavalcante ◽  
Alexandre Pio Viana ◽  
Paulo Ricardo dos Santos ◽  
Sandra da Costa Preisigke ◽  
Rodrigo Moreira Ribeiro ◽  
...  
Keyword(s):  
Recurrent Selection ◽  
Fruit Production ◽  
Important Variable ◽  
Passion Fruit ◽  
Soluble Solids ◽  
Direct Selection ◽  
Production Traits ◽  
Average Mass ◽  
Explanatory Variables ◽  
Half Sibling

Abstract The present study was developed to identify the direct and indirect effects of fruit production traits in passion fruit on traits of agronomic interest as well as determine possible changes in associations between the characters after three cycles of recurrent selection. Twenty three half-sibling progenies were evaluated for the characteristics number of fruits per plant; fruit mass per plant (g); pulp percentage (%); fruit length and diameter (mm); peel thickness (mm); total soluble solids content (ºBrix); pH; and yield per plant (kg). Fruit production per plant was considered the main variable, while the others were considered explanatory variables. Within-family heritability (h2ad) values were lower than the mean heritability of the progeny (h2mp). Path analysis revealed that the direct selection of genotypes with higher number of fruits or fruit average mass results in increased production per plant; however, indirect selection is inefficient in providing simultaneous gains. Therefore, by observing the correlations throughout selection cycles, it can be stated that although production per plant is the most important variable, preference should be given to the use of selection indices, as there are better chances of obtaining gains for fruit quality and production traits in selection across half-sibling passion fruit progenies.

Breeding for reduced methane emissions in extensive UK sheep systems

2012 ◽  
Vol 150 (5) ◽  
pp. 570-583 ◽  
Author(s):  
D. J. COTTLE ◽  
J. CONINGTON
Keyword(s):  
Production Systems ◽  
Selection Index ◽  
Farming Systems ◽  
Cost Effective ◽  
Carbon Price ◽  
Methane Emissions ◽  
Direct Selection ◽  
Production Traits ◽  
The Uk ◽  
Carbon Prices

SUMMARYSelection index theory was used to model the effects of methane (CH4) production in the breeding objective on genetic responses in Scottish Blackface sheep in hill production systems in the UK. A range of economic values (EVs) were assumed for CH4 production calculated from possible carbon prices (£/t CO2 equivalent (CO2-e)). The implicit price of carbon required for maintenance of CH4 levels or to reduce CH4 production by 0·1 kg/head/yr in a hill flock was calculated. The predicted genetic changes in CH4 production from current selection programmes that have an implicit methane EV of zero were calculated. Correlations between production traits and CH4 production were sampled from assumed normal distributions, as these correlations are currently unknown. Methane emissions are likely to increase at a rate of c. 3 kg CO2-e/ewe/yr as a result of using current industry selection indices in hill sheep farming systems in the UK. Breeding objectives for more productive hill sheep include reducing lamb losses and rearing more, heavier lambs. By placing a cost on carbon emissions to halt the genetic increase in methane, heavy penalties will be incurred by farmers in terms of reduced productivity. This amounts to £6/ewe/yr or a 5% discounted loss of £2851 per 100 ewe flock over a 10-year selection horizon. If the correlations between production traits and CH4 are positive (as expected) then an implicit carbon price of c. £272/t CO2-e is required for no genetic increase in CH4 production if methane is not measured and c. £50/t CO2-e if methane could be measured. Achievement of government targets for the whole economy of a 20% reduction in greenhouse gases (GHGs) over a 30-year period would require carbon prices (/t CO2-e) of £1396 (indirect selection) or £296 (direct selection) for the sheep industry to achieve a 20% reduction entirely via a genetic change of c. –0·1 kg methane/head/yr. These carbon prices are placed in the context of possible government policies. A combination of genetic and non-genetic measures will probably be required for cost-effective reduction in methane production to meet government targets.

scholarly journals Early selection efficiency for recommendation of Eucalyptus sp.

2020 ◽  
Vol 8 (3) ◽  
pp. 304-315
Author(s):  
Yanca Araujo Frias ◽  
Eliel Alves Ferreira ◽  
Victor Hugo Cruz ◽  
Daniel Pedrosa Alves ◽  
Evandro Pereira Prado ◽  
...  
Keyword(s):  
Plant Height ◽  
Block Design ◽  
Selection Index ◽  
Early Selection ◽  
Direct Selection ◽  
Selection Efficiency ◽  
Breast Height ◽  
Randomized Block Design ◽  
Progeny Tests ◽  
Combined Selection

This paper aims to estimate genetic and phenotypical parameters to assess the viability of early selection in progeny tests of Eucalyptus sp. We analyzed data from experiments conducted in the state of Minas Gerais, Brazil. The evaluated traits were diameter at breast height and plant height in 482 progenies of full sibs under randomized block design, into nine experiments: four of which were assessed at progenies mean level, and five assessed at individuals mean level. It were evaluated the predicted gains with combined selection index under 5, 10 and 20% of selection; the coincidence among selected families in juvenile and adult ages, and the efficiency of early selection. Results indicated that the procedures were efficient in most of the scenarios, and the gains comparable to the direct selection on tree harvest age.

scholarly journals GENETIC CONTROL OF VARIATION IN A SELECTED POPULATION OF RUSSIAN WILD RYEGRASS (ELYMUS JUNCEUS)

1976 ◽  
Vol 56 (2) ◽  
pp. 275-280
Author(s):  
T. LAWRENCE
Keyword(s):  
Genetic Control ◽  
Seed Yield ◽  
Seed Weight ◽  
Dry Matter ◽  
Recurrent Selection ◽  
Direct Selection ◽  
Adult Plant ◽  
Dry Matter Yield ◽  
Seedling Characters ◽  
Additive Control

Progenies from a five-genotype diallel cross in Russian wild ryegrass, Elymus junceus Fisch., were studied to assess the pattern of genetic control for F1 seed weight and a number of seedling and adult plant characters. Variation in F1 seed weight was largely determined by the maternal parent, but some control by the pollen parent was apparent. Of the seedling characters, days to emerge, rate of leaf appearance, rate of tiller appearance, and seedling dry matter yield, only days to emerge showed additive variance which is amenable to direct selection. The other three characters could be most easily exploited by a recurrent selection program. The adult plant characters, date of inflorescence appearance, P content of the forage, and organic matter digestibility indicated strong additive control which is amenable to direct selection. Dry matter yield and seed yield also showed strong additive control which was accompanied by specific combining ability and weak maternal effects suggesting good progress should be possible by direct selection methods but crossing the selections in a diallel fashion prior to formation of synthetics might be desirable. The seedling characters, rate of leaf and tiller appearance and seedling dry matter yield were interrelated and associated with adult plant yield, thus offering the possibility of screening seedlings for these characters in a recurrent selection program for improved forage or seed yield.

scholarly journals Corrigendum to: Consequences of genetic selection for environmental impact traits on economically important traits in dairy cows

2018 ◽  
Vol 58 (10) ◽  
pp. 1966
Author(s):  
Purna Kandel ◽  
Sylvie Vanderick ◽  
Marie-Laure Vanrobays ◽  
Hélène Soyeurt ◽  
Nicolas Gengler
Keyword(s):  
Dairy Cows ◽  
Body Condition Score ◽  
Genetic Correlations ◽  
Genetic Selection ◽  
Selection Response ◽  
Direct Selection ◽  
Correlated Response ◽  
Production Traits ◽  
Ch4 Emissions ◽  
Natural Logarithm

Methane (CH4) emission is an important environmental trait in dairy cows. Breeding aiming to mitigate CH4 emissions require the estimation of genetic correlations with other economically important traits and the prediction of their selection response. In this study, test-day CH4 emissions were predicted from milk mid-infrared spectra of Holstein cows. Predicted CH4 emissions (PME) and log-transformed CH4 intensity (LMI) computed as the natural logarithm of PME divided by milk yield (MY). Genetic correlations of PME and LMI with traits used currently were approximated from correlations between estimated breeding values of sires. Values were for PME with MY 0.06, fat yield (FY) 0.09, protein yield (PY) 0.13, fertility 0.17; body condition score (BCS) –0.02; udder health (UDH) 0.22; and longevity 0.22. As expected by its definition, values were negative for LMI with production traits (MY –0.61; FY –0.15 and PY –0.40) and positive with fertility (0.36); BCS (0.20); UDH (0.08) and longevity (0.06). The genetic correlations of 33 type traits with PME ranged from –0.12 to 0.25 and for LMI ranged from –0.22 to 0.18. Without selecting PME and LMI (status quo) the relative genetic change through correlated responses of other traits were in PME by 2% and in LMI by –15%, but only due to the correlated response to MY. Results showed for PME that direct selection of this environmental trait would reduce milk carbon foot print but would also affect negatively fertility. Therefore, more profound changes in current indexes will be required than simply adding environmental traits as these traits also affect the expected progress of other traits.

scholarly journals Genetic progress and potential of common bean families obtained by recurrent selection

2015 ◽  
Vol 15 (4) ◽  
pp. 218-226 ◽  
Author(s):  
Anatércia Ferreira Alves ◽  
José Ângelo Nogueira de Menezes Júnior ◽  
Vanessa Maria Pereira Silva Menezes ◽  
José Eustáquio de Souza Carneiro ◽  
Pedro Crescêncio Souza Carneiro ◽  
...  
Keyword(s):  
Common Bean ◽  
Genetic Gain ◽  
Recurrent Selection ◽  
Population Cycle ◽  
Base Population ◽  
Genetic Progress ◽  
Simultaneous Evaluation ◽  
Agronomically Important Traits

Abstract The objective of this study was to estimate the genetic gain of two recurrent selection cycles in common bean breeding and identify families with the potential to generate superior lines. The base population, cycle zero (C0), was obtained by combining 20 carioca bean parents, populations with favorable phenotypes for several agronomically important traits. The parents were recombined in a circulant diallel scheme, in which each parent participated in two crosses, generating 20 populations. From these populations, families were derived and evaluated for three seasons in the generations F2:3, F2:4 and F2:5. The same procedures of recombination and evaluation in C0 were performed in cycle one (CI). The genetic gain for yield, estimated from the simultaneous evaluation of the 40 best families of each cycle, was 8.6%. Families with potential to generate superior lines to cultivar Pérola were identified, especially among the CI families.

The incorporation of fertility indices in genetic improvement programmes

2001 ◽  
Vol 26 (1) ◽  
pp. 237-249 ◽  
Author(s):  
J.E. Pryce ◽  
R.F. Veerkamp
Keyword(s):  
Genetic Variance ◽  
Selection Index ◽  
Genetic Correlations ◽  
Live Weight ◽  
Parameter Estimates ◽  
Phenotypic Variance ◽  
Production Traits ◽  
Genetic Progress ◽  
Detection Rates ◽  
Days Open

AbstractIn recent years there has been considerable genetic progress in milk production. Yet, increases in yield have been accompanied by an apparent lengthening of calving intervals, days open, days to first heat and a decline in conception rates, which appears to be both at the genetic and phenotypic level. Fertility has a high relative economic value compared to production traits such as protein, making it attractive to include in a breeding programme. To do this there needs to be genetic variance in fertility. Measures of fertility calculated from service dates have a small genetic compared to phenotypic variance, hence heritability estimates are small, typically less than 5%, although coefficients of genetic variance are comparable to those of production traits. Heritabilities of commencement of luteal activity determined using progesterone profiles are generally higher, and have been reported as being from 0.16 to 0.28, which could be because of a more precise quantification of genetic variance, as management influences such as delaying insemination and heat detection rates are excluded. However, it might not be the use of progesterone profiles alone, as days to first heat observed by farm staff has a heritability of 0.15. The most efficient way to breed for improved fertility is to construct a selection index using the genetic and phenotypic parameter estimates of all traits of interest in addition to their respective economic values. Index traits for fertility could include measures such as calving interval, days open, days to first service, or days to first heat but there may also be alternative measures. Examples include traits related to energy balance, such as live weight and condition score (change), both of which have higher heritabilities than fertility measures and have genetic correlations of sufficient magnitude to make genetic progress by using them feasible. To redress the balance between fertility and production, some countries already publish genetic evaluations of fertility including: Denmark, Finland, France, Germany, Israel, The Netherlands, Norway and Sweden.

scholarly journals Protein phenotypes and productive traits in Landrace, Large White and Duroc swine

1995 ◽  
Vol 25 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Claudia Helena Tagliaro ◽  
Maria Helena Lartigau Pereira Franco ◽  
Werner Meincke ◽  
Gilberto Silva
Keyword(s):  
Weight Gain ◽  
Selection Index ◽  
Daily Weight Gain ◽  
Production Traits ◽  
Southern Brazil ◽  
Feed Conversion ◽  
Large White ◽  
Performance Variables ◽  
Phosphogluconate Dehydrogenase ◽  
Productive Traits

Fourteen protein systems coded by 15 structural loci were typed by horizontal electrophoresis to determine possible associations betweem the protein phenotypes and productive traits in Landrace (N=109), Largo White (N= 116) and Duroe (N=57) pigs, reared in Southern Brazil. Signiticant associations between protein phenotypes and production traits were detected. The most consistent interaction were observed between two protein systems (phosphogluconate dehydrogenase - Pgd and Hemopexin -Hpx) and at least one of the four performance variables considered. In Duroc breed, the Pgd phenotypes were associated with daily weight gain (P < 0.01), feed conversion ratio (P < 0.01) and selection index (P < 0.001), while in Landrace significant associations were observed only with feed convertion ratio (P < 0.05). The Hpx phenotypes were associated with daily weight gain (P < 0.05) and backfat thickness (P < 0.05) in Large White and with this last variable (P < 0.01) and selection index (P < 0.05) in Duroc pigs. Since these results had not been reported previously, turther studies are need to confirm these associations.

scholarly journals Genetic variation at RYR1, IGF2, FUT1, MUC13, and KPL2 mutations affecting production traits in Chinese commercial pig breeds

2013 ◽  
Vol 58 (No. 2) ◽  
pp. 65-70 ◽  
Author(s):  
G.R. Ruan ◽  
Y.Y. Xing ◽  
Y. Fan ◽  
R.M. Qiao ◽  
X.F. He ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Production Traits ◽  
Large White ◽  
Low Frequencies ◽  
High Frequencies ◽  
E Coli ◽  
Resistant Lines ◽  
Defective Allele ◽  
Breeding Schemes ◽  
Combined Selection

The identification of causative mutations affecting economically important traits has benefited the worldwide pig industry. We investigated the genetic variation at five loci including RYR1, IGF2, FUT1, MUC13, and KPL2 affecting traits related to production, reproduction, and disease resistance in a sample of 8009 pigs representing 3 commercial breeds (Duroc, Landrace, and Large White) from 28 farms in China. We found that all breeds, especially Duroc pigs, have high frequencies of favourable alleles for lean production and stress resistance at the IGF2 and RYR1 loci. However, all breeds have low frequencies of the diarrhea-resistant allele of FUT1, indicating that multigenerational selection is required for E. coli F18<sup>+</sup> resistant pigs. No linkage disequilibrium was found between the RYR1 and FUT1 loci on pig chromosome 6, supporting the possibility of combined selection for both F18 and stress-resistant pigs. Relatively high frequencies (&gt; 0.5) of the MUC13 allele conferring resistance to E. coli F4ac were found in all three breeds with the highest frequency in Duroc pigs, suggesting that the breeders can establish F4ac diarrhea-resistant lines in a few generations. No defective allele at the KPL2 locus causing immotile short-tail sperms was found in Large White pigs of American, Canadian, Danish, English, and French origin, supporting the conclusion that the KPL2 defective allele is present exclusively in Finnish Large White pigs. These results provide useful information for pig breeding schemes in China.

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