scholarly journals Breeding programs for smallholder sheep farming systems: I. Evaluation of alternative designs of breeding schemes

2014 ◽  
Vol 131 (5) ◽  
pp. 341-349 ◽  
Author(s):  
S. Gizaw ◽  
B. Rischkowsky ◽  
A. Valle-Zárate ◽  
A. Haile ◽  
J.A.M. van Arendonk ◽  
...  
Keyword(s):  
Farming Systems ◽  
Breeding Programs ◽  
Breeding Schemes ◽  
Alternative Designs

scholarly journals Genetic improvement of indigenous Greek sheep and goat breeds

2020 ◽  
Vol 71 (1) ◽  
pp. 2063
Author(s):  
A. ARGYRIADOU ◽  
A. I. GELASAKIS ◽  
G. BANOS ◽  
G. ARSENOS
Keyword(s):  
Genetic Improvement ◽  
Genetic Basis ◽  
Small Ruminant ◽  
Reproductive Technologies ◽  
Indigenous Populations ◽  
Integrative Approach ◽  
Breeding Programs ◽  
Improvement Potential ◽  
Breeding Schemes

The objective of the study was twofold: (i) to review the genetics of production and resilience traits of indigenous Greek small ruminant breeds as well as the evolution of national breeding programs, and (ii) explore innovative and feasible approaches to overcome the challenges and constraints towards improving these breeds and enhancing the sustainability of the small ruminant sector. Previous studies on the genetic basis of production and resilience traits of indigenous breeds revealed high improvement potential. However, the lack of follow-up action has failed to produce applicable results. Thus, implementation of scientific findings in existing breeding programs for these breeds is extremely limited. The latter has contributed to the overall poor success of such programs. Furthermore, due to the fact that most farmers do not comprehend the strategic importance of genetic improvement and lack motivation for self-funding, breeding programs have mostly relied on European or government funding; the latter has resulted in intermittent implementation. Therefore, most programs failed to improve performance of indigenous Greek breeds, many of which were consequently replaced by foreign breeds of higher productivity and documented merit. In order to facilitate the design of breeding schemes and overcome the challenges towards improvement of indigenous breeds, an integrative approach is necessary. The latter should be based on identification of specific breeding objectives, reflecting the priorities and needs of the sector, as well as the capacity of the indigenous populations. Scientific advances exemplified by genomic selection and novel reproductive technologies will enable faster and more effective genetic improvement. The overall approach is expected to enhance the competitiveness of indigenous Greek small ruminant breeds and the sustainability of the sector.

scholarly journals Agronomically important traits of emmer wheat

2012 ◽  
Vol 58 (No. 8) ◽  
pp. 341-346 ◽  
Author(s):  
P. Konvalina ◽  
I. Capouchová ◽  
Z. Stehno
Keyword(s):  
Harvest Index ◽  
Agronomic Traits ◽  
Farming Systems ◽  
Emmer Wheat ◽  
Breeding Programs ◽  
Low Input ◽  
Yield Rate ◽  
Wheat Diseases ◽  
Negative Factors ◽  
Agronomically Important Traits

Particular agronomic traits of six landraces of Triticum diccocum Schrank (Schuebl) were studied during three years in Prague and Česk&eacute; Budějovice localities, Czech Republic. The analysis of tolerance to drought by using the method of <sup>13</sup>C discrimination (CID) was also focused on in the research. All the tested varieties were resistant to usual wheat diseases. An inclination of particular varieties to lodging and a low harvest index rate (0.33) were negative factors having a significant effect on the yield rate. Meanwhile, all the varieties contained a high percentage of proteins in grain (17.92%) which was an important advantage in low input conditions. The landraces of emmer wheat also proved to be more tolerant to drought (CID = 25.82&permil;) than check varieties of bread wheat (CID = 26.70&permil;). Results of the research showed that some of the emmer landraces may be successfully grown and used directly in low-input farming systems or in breeding programs focused on the breeding of suitable varieties for low-input farming. &nbsp;

Effects of reduced variance due to selection in open nucleus breeding systems

1983 ◽  
Vol 34 (1) ◽  
pp. 53 ◽  
Author(s):  
JP Mueller ◽  
JW James
Keyword(s):  
Genetic Variance ◽  
Breeding Systems ◽  
Breeding Programs ◽  
Transfer Rates ◽  
Constant Variance ◽  
High Heritability ◽  
Breeding Schemes ◽  
Nucleus Breeding ◽  
Open Nucleus ◽  
Parameter Theory

In the design of breeding programs the consideration of open nucleus breeding systems may result in a useful alternative. The available theory dealing with these systems assumes constant parameters, but a more exact approach would take into account the possible changes in genetic variance. Numerical evaluation of formulae allowing for loss of genetic variance due to linkage disequilibrium and increase of variance due to mixing groups with different breeding values, suggests that optimum transfer rates, as predicted from the constant parameter theory, are in close agreement with the actual values; however, genetic gain is overestimated by about 20 % in common cattle and sheep nucleus breeding schemes for traits with high heritability, but less for traits with low heritability. The advantage of opening the nucleus is approximated well by constant variance theory.

scholarly journals Breeding programmes for smallholder sheep farming systems: II. Optimization of cooperative village breeding schemes

2014 ◽  
Vol 131 (5) ◽  
pp. 350-357 ◽  
Author(s):  
S. Gizaw ◽  
J.A.M. van Arendonk ◽  
A. Valle-Zárate ◽  
A. Haile ◽  
B. Rischkowsky ◽  
...  
Keyword(s):  
Farming Systems ◽  
Breeding Programmes ◽  
Breeding Schemes ◽  
Village Breeding

scholarly journals Assessment of Tomato Recombinant Lines in Conventional and Organic Farming Systems for Productivity and Fruit Quality Traits

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 129
Author(s):  
Ilias D. Avdikos ◽  
Rafail Tagiakas ◽  
Ioannis Mylonas ◽  
Ioannis N. Xynias ◽  
Athanasios G. Mavromatis
Keyword(s):  
Fruit Quality ◽  
Farming Systems ◽  
Hybrid Vigor ◽  
Yield Potential ◽  
High Input ◽  
Breeding Programs ◽  
Low Input ◽  
Organic Farming Systems ◽  
Additive Genes ◽  
Single Cross Hybrids

It is estimated that more than 95% of organic agriculture is based on crop cultivars that were bred for the conventional high-input sector. Most selections were made through conventional breeding programs and lack important traits required under organic and low-input conditions. Hybrids are the most common type of cultivars used in tomato because of heterosis. In tomato, continuous selfing enabled homozygosity to exploit favorable additive genes, resulting in the so-called inbred vigor. This paper presented the possibility to express inbred vigor at a level equal to or greater than hybrid vigor in tomato when cultivated under organic low input conditions. The evaluation of the recombinant lines produced through classical reverse breeding from four F1 single cross hybrids was done at low- and high-input farming systems. The results show that, following the appropriate breeding process in early generation selection and under low-input conditions, it is possible to produce recombinant lines, demonstrating inbred vigor in yield potential and fruit quality. These genetic materials can stand as new dynamic cultivars intended for cultivation in organic, low-input, or high-input conditions, depending on their performance in different farming systems at the later stages of evaluation.

scholarly journals Multi-objective optimized breeding strategies

2017 ◽  
Author(s):  
Deniz Akdemir ◽  
Julio Isidro Sánchez
Keyword(s):  
Mathematical Optimization ◽  
Breeding Population ◽  
Data Sets ◽  
Breeding Strategies ◽  
Objective Functions ◽  
Multi Objective Optimization ◽  
Breeding Programs ◽  
Multi Objective ◽  
Breeding Schemes ◽  
Definition Of

Multi-objective optimization is an emerging field in mathematical optimization which involves optimization a set of objective functions simultaneously. The purpose of most plant and animal breeding programs is to make decisions that will lead to sustainable genetic gains in more than one traits while controlling the amount of co-ancestry in the breeding population. The decisions at each cycle in a breeding program involve multiple, usually competing, objectives; these complex decisions can be supported by the insights that are gained by using the multi-objective optimization principles in breeding. The discussion here includes the definition of several multi-objective optimized breeding approaches and the comparison of these approaches with the standard multi-trait breeding schemes such as tandem selection, culling and index selection. We have illustrated the newly proposed methods with two empirical data sets and with simulations.

scholarly journals Effects of Different Strategies for Exploiting Genomic Selection in Perennial Ryegrass Breeding Programs

2020 ◽  
Vol 10 (10) ◽  
pp. 3783-3795
Author(s):  
Hadi Esfandyari ◽  
Dario Fè ◽  
Biructawit Bekele Tessema ◽  
Lucas L. Janss ◽  
Just Jensen
Keyword(s):  
Genomic Selection ◽  
Perennial Ryegrass ◽  
Genetic Gain ◽  
Additive Genetic Variance ◽  
Phenotypic Selection ◽  
Breeding Program ◽  
Breeding Programs ◽  
Traditional Program ◽  
Breeding Schemes ◽  
Estimated Breeding Values

Genomic selection (GS) is a potential pathway to accelerate genetic gain for perennial ryegrass (Lolium perenne L.). The main objectives of the present study were to investigate the level of genetic gain and accuracy by applying GS in commercial perennial ryegrass breeding programs. Different scenarios were compared to a conventional breeding program. Simulated scenarios differed in the method of selection and structure of the breeding program. Two scenarios (Phen-Y12 and Phen) for phenotypic selection and three scenarios (GS-Y12, GS and GS-SP) were considered for genomic breeding schemes. All breeding schemes were simulated for 25 cycles. The amount of genetic gain achieved was different across scenarios. Compared to phenotypic scenarios, GS scenarios resulted in substantially larger genetic gain for the simulated traits. This was mainly due to more efficient selection of plots and single plants based on genomic estimated breeding values. Also, GS allows for reduction in waiting time for the availability of the superior genetic materials from previous cycles, which led to at least a doubling or a trebling of genetic gain compared to the traditional program. Reduction in additive genetic variance levels were higher with GS scenarios than with phenotypic selection. The results demonstrated that implementation of GS in ryegrass breeding is possible and presents an opportunity to make very significant improvements in genetic gains.

scholarly journals Short-term effects of controlled mating and selection on the genetic variance of honeybee populations

Heredity ◽  
2021 ◽  
Author(s):  
Manuel Du ◽  
Richard Bernstein ◽  
Andreas Hoppe ◽  
Kaspar Bienefeld
Keyword(s):  
Genetic Variance ◽  
Selection Criterion ◽  
Performance Criterion ◽  
Performance Criteria ◽  
Adaptation To Climate Change ◽  
Short Term ◽  
Breeding Programs ◽  
Breeding Schemes ◽  
And Performance ◽  
Modern Breeding

AbstractDirectional selection in a population yields reduced genetic variance due to the Bulmer effect. While this effect has been thoroughly investigated in mammals, it is poorly studied in social insects with biological peculiarities such as haplo-diploidy or the collective expression of traits. In addition to the natural adaptation to climate change, parasites, and pesticides, honeybees increasingly experience artificial selection pressure through modern breeding programs. Besides selection, many honeybee breeding schemes introduce controlled mating. We investigated which individual effects selection and controlled mating have on genetic variance. We derived formulas to describe short-term changes of genetic variance in honeybee populations and conducted computer simulations to confirm them. Thereby, we found that the changes in genetic variance depend on whether the variance is measured between queens (inheritance criterion), worker groups (selection criterion), or both (performance criterion). All three criteria showed reduced genetic variance under selection. In the selection and performance criteria, our formulas and simulations showed an increased genetic variance through controlled mating. This newly described effect counterbalanced and occasionally outweighed the Bulmer effect. It could not be observed in the inheritance criterion. A good understanding of the different notions of genetic variance in honeybees, therefore, appears crucial to interpreting population parameters correctly.

scholarly journals Impact of Genomic and Transcriptomic Resources on Apiaceae Crop Breeding Strategies

2021 ◽  
Vol 22 (18) ◽  
pp. 9713
Author(s):  
Fabio Palumbo ◽  
Alessandro Vannozzi ◽  
Gianni Barcaccia
Keyword(s):  
Molecular Data ◽  
Apium Graveolens ◽  
Rna Seq ◽  
Foeniculum Vulgare ◽  
Breeding Programs ◽  
Plastid Genomes ◽  
Economic Weight ◽  
New Varieties ◽  
Breeding Schemes ◽  
Nms Systems

The Apiaceae taxon is one of the most important families of flowering plants and includes thousands of species used for food, flavoring, fragrance, medical and industrial purposes. This study had the specific intent of reviewing the main genomics and transcriptomic data available for this family and their use for the constitution of new varieties. This was achieved starting from the description of the main reproductive systems and barriers, with particular reference to cytoplasmic (CMS) and nuclear (NMS) male sterility. We found that CMS and NMS systems have been discovered and successfully exploited for the development of varieties only in Foeniculum vulgare, Daucus carota, Apium graveolens and Pastinaca sativa; whereas, strategies to limit self-pollination have been poorly considered. Since the constitution of new varieties benefits from the synergistic use of marker-assisted breeding in combination with conventional breeding schemes, we also analyzed and discussed the available SNP and SSR marker datasets (20 species) and genomes (8 species). Furthermore, the RNA-seq studies aimed at elucidating key pathways in stress tolerance or biosynthesis of the metabolites of interest were limited and proportional to the economic weight of each species. Finally, by aligning 53 plastid genomes from as many species as possible, we demonstrated the precision offered by the super barcoding approach to reconstruct the phylogenetic relationships of Apiaceae species. Overall, despite the impressive size of this family, we documented an evident lack of molecular data, especially because genomic and transcriptomic resources are circumscribed to a small number of species. We believe that our contribution can help future studies aimed at developing molecular tools for boosting breeding programs in crop plants of the Apiaceae family.

scholarly journals Effects of Different Strategies for Exploiting Genomic Selection in Perennial Ryegrass Breeding Programs

2020 ◽  
Author(s):  
Hadi Esfandyari ◽  
Dario Fè ◽  
Biructawit Bekele Tessema ◽  
Lucas L. Janss ◽  
Just Jensen
Keyword(s):  
Genomic Selection ◽  
Perennial Ryegrass ◽  
Genetic Gain ◽  
Additive Genetic Variance ◽  
Phenotypic Selection ◽  
Breeding Program ◽  
Breeding Programs ◽  
Traditional Program ◽  
Breeding Schemes ◽  
Efficient Selection

AbstractGenomic selection (GS) is a potential pathway to accelerate genetic gain for perennial ryegrass (Lolium perenne L.). The main objectives of the present study were to investigate the level of genetic gain and accuracy by applying GS in commercial perennial ryegrass breeding programs. Different scenarios were compared to a conventional breeding program. Simulated scenarios differed in the method of selection and structure of the breeding program. Two scenarios (Phen-Y12 and Phen) for phenotypic selection and three scenarios (GS-Y12, GS and GS-SP) were considered for genomic breeding schemes. All breeding schemes were simulated for 25 cycles. The amount of genetic gain achieved was different across scenarios. Compared to phenotypic scenarios, GS scenarios resulted in a significantly larger genetic gain for the simulated traits. This was mainly due to more efficient selection of plots and single plants based on GEBV. Also, GS allows for reduction in cycle time, which led to at least a doubling or a trebling of genetic gain compared to the traditional program. Reduction in additive genetic variance levels were higher with GS scenarios than with phenotypic selection. The results demonstrated that implementation of GS in ryegrass breeding is possible and presents an opportunity to make very significant improvements in genetic gains.

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