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| Registros recuperados: 97 | |
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| Barbosa,Flavia C. R; Casela,Carlos R; Pfenning,Ludwig H; Santos,Fredolino G. |
| The main objective of this work was to identify sources of resistance in sorghum (Sorghum bicolor) to Peronosclerospora sorghi, the causal agent of downy mildew, through the evaluation of 42 sorghum genotypes under natural infection in the field. Genotypes were planted in single row plots between two rows of the susceptible line SC283, planted 30 days before, to act as spreader rows, in two separate nurseries. The experimental design was a completely randomized block design with three replications. Sorghum genotypes CMSXS156, CMSXS157, CMSXS243, TxARG-1, 8902, 9902054, 9910032, 9910296, Tx430, QL-3, SC170-6-17, CMSXS762 and BR304 were classified as highly resistant in both nurseries. Among these, SC170-6-17 and 9910296 showed 0% systemic infection. Results... |
| Tipo: Info:eu-repo/semantics/other |
Palavras-chave: Sorghum bicolor; Diseases; Genetic; Resistance; Downy mildew. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-41582005000500010 |
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| Batista, Frederico; Boudry, Pierre; Lapegue, Sylvie; Heurtebise, Serge; Monteiro, C. C.. |
| The Portuguese oyster, Crassostrea angulata, was introduced from Portugal to the French Atlantic Coast in the 1860s. C. angulata quickly settled and expanded and leaded to the development of a new aquacultural industry in France. In the late 1960s, mortality associated with the detection of an iridovirus, led to the wipe out of C. angulata from French Atlantic waters and to the massive introduction of C. gigas to sustain production. In Southern Europe, similar symptoms were also observed in natural stocks of C. angulata from Sado River (Portugal) and from the area of Cadiz (Spain). Nowadays, only very few «pure» populations of C. angulata remain in southern Europe. These populations are potentially endangered by the current expansion of C. gigas... |
| Tipo: Text |
Palavras-chave: Selection; Hybridization; Settlement pattern; Population genetic; Genetic; Oysters; Crassostrea angulata; Crassostrea gigas. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-3310.pdf |
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| Batista, Frederico; Fonseca, Vera; Ben-hamadou, Radhouan; Taris, Nicolas; Henriques, Maria; Boudry, Pierre. |
| Unlike in some crops, no large heterotic effects have been observed in most farmed animals. Interestingly, significant hybrid vigour for some traits has been reported in the Pacific oyster, Crassostrea gigas. Crossbreeding between closely related taxa can be seen as an efficient way to exploit the dominance component of the genetic variance of a trait. Factorial crosses between the Portuguese oyster C. angulata (from Sado estuary, Portugal) and C. gigas (from Seudre estuary, France) were done to evaluate the aquaculture potential of hybrids. Juveniles of the different progenies were reared in Ria Formosa (Portugal) under usual farming conditions. The genetic confirmation of all progenies was done using mitochondrial and nuclear markers in order to detect... |
| Tipo: Text |
Palavras-chave: Hybridization; Crassostrea angulata; Crassostrea gigas; Genetic; Oyster. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/acte-3429.pdf |
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| Batista, Frederico; Leitao, Alexandra; Huvet, Arnaud; Lapegue, Sylvie; Heurtebise, Serge; Boudry, Pierre. |
| The taxonomic status of the Portuguese oyster Crassostrea angulata and the Pacific oyster Crassostrea gigas has often been a matter of controversy. Based on larval shell morphology, experimental hybridisation and electrophoretic studies of enzyme polymorphism several authors have considered these two species as being synonymous. During the recent years, several genetic studies based on mitochondrial DNA and microsatellites data have provided evidences that the two taxa are genetically distinct although closely related. Furthermore, karyotype analyses have also highlighted the close genetic similarity of these taxa in comparison with other cupped oyster species. However, a comparative analysis of restriction enzymes ideograms revealed differences between... |
| Tipo: Text |
Palavras-chave: Geographical origin; Phylogenetic; Genetic; Taxonomic status; Crassostrea angulata; Oyster. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-3433.pdf |
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| Becerril,Carlos M.; Wilcox,Charles J.; Guerrero,Victor M.. |
| Correlations of measures of percentages of white coat color, five measures of production and two measures of reproduction were obtained from 4293 first lactation Holsteins from eight Florida dairy farms. Percentages of white coat color were analyzed as recorded and transformed by an extension of Box-Cox procedures. Statistical analyses were by derivative-free restricted maximum likelihood (DFREML) with an animal model. Phenotypic and genetic correlations of white percentage (not transformed) were with milk yield, 0.047 and 0.097; fat yield, 0.002 and 0.004; fat percentage, -0.047 and -0.090; protein yield, 0.024 and 0.048; protein percentage, -0.070 and -0.116; days open, -0.012 and -0.065; and calving interval, -0.007 and -0.029. Changes in magnitude of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Holstein; Phenotypic; Genetic; Environmental. |
| Ano: 1996 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-84551996000400009 |
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| Bedier, Edouard; Langlade, Aime; Angeri, Stéphane; Brizard, Raphael; Nerlovic, V.; Glize, Philippe; Haffray, Philippe. |
| Since the outbreaks of the parasitosis with Marteilia refringens and Bonamia ostreae in the last 60's, the French production of the European flat oyster dropped from 20000 mT to less than 1500 mT currently, leaving the French shellfish farming in situation of virtually monoculture of the Pacific cupped oyster Crassostrea gigas. To sustain this traditional culture, Ifremer has developed, at the experimental level, a genetic selection for a better tolerance to Bonamia ostreae which led to an improvement of survivals. The transfer of these results to the business scale requires the control of the reproduction in hatchery and the adaptation of the cycle of production to the constraints of seedlings in deep water as practised in Brittany (France). That's why a... |
| Tipo: Text |
Palavras-chave: Selection; Genetic; Bonamia ostreae; Parasite; Ostrea edulis; Oyster. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-3313.pdf |
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| Benabdelmouna, Abdellah; Nadolna, Katarzyna; Ledu, Christophe. |
| Aneuploidy (or alteration of chromosome number) has been frequently described in diploid, triploid and tetraploid C. gigas. In diploid Pacific oysters, aneuploidy affects 1 to 3 chromosomes in up to 35% of the somatic cells and is positively correlated with inferior growth of the animal and thus could be associated with significant economic loss in this major aquaculture species. In polyploid Pacific oysters, aneuploidy was shown to be more heavily frequent and is linked to reversion to lower ploidy levels and is at the origin of aberrant gametes formation. In this context, identification of individual chromosomes involved in aneuploidy events both in somatic and germinal cells would be an important step towards the study of the exact occurrence of this... |
| Tipo: Text |
Palavras-chave: Chromosome; Aneuploidy; Genetic; Crassostrea gigas; Pacific oysters. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/acte-3502.pdf |
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| Boudry, Pierre. |
| Dr. Boudry focussed his talk on oysters, which are the most important bivalve species produced world wide (more than 4 million tons). One of the main characteristic of bivalve aquaculture is that most of the juveniles ("seed or "spat") are collected from natural recruitment (e.g. 100% of the European mussel production). Hatchery propagation is used in the case of introduced species (e.g. Crassostrea gigas in USA) or limited natural recruitment. The most significant genetic improvement for the production of Pacific oyster (C. gigas) to date has been obtained through the breeding of triploids, especially since the development of tetraploids. Triploidy lead to highly reduced gametogenesis and, as a result better growth and survival. Many quantitative... |
| Tipo: Text |
Palavras-chave: Crassostrea gigas; Oyster; Genetic variability; Bivalve shellfish; Selective breeding; Genetic. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/acte-3479.pdf |
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| Boudry, Pierre. |
| The most significant genetic improvement for the production of Pacific oyster (Crassostrea gigas) up until now has been obtained through the production of triploids, particularly since the development of tetraploids in the mid 90s. Alternatively, quantitative genetics studies suggest that significant gains could be obtained in traits of aquacultural interest. However, the limited extent of hatchery propagation (compared with natural recruitment) in some countries and/or technical difficulties and biological characteristics of this species have retarded the development of selective breeding programs for C. gigas. Individual selection can however be performed easily in such a highly fecund species, though it often leads to small effective population sizes... |
| Tipo: Text |
Palavras-chave: Selective breeding; Genetic; Crassostrea gigas; Pacific oysters. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/acte-3462.pdf |
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| Boudry, Pierre. |
| To date, the most significant genetic improvement for the production of Pacific oyster (Crassostrea gigas) has been obtained through the production of triploids, especially since the development of tetraploids. Quantitative genetics studies suggest that significant gains, for disease resistance or other traits, could be obtained in diploids. However, the limited extent of hatchery-propagation (versus natural recruitment) and/or various technical difficulties and biological characteristics of the species have retarded the development of selective breeding programs. In the U.S.A., Australia and New Zealand, family-based selective breeding programs have recently been initiated to improve growth, disease tolerance and yield. In Europe, where both natural and... |
| Tipo: Text |
Palavras-chave: Microsatellite markers; Crassostrea gigas; Selective breeding; Triploid; Pacific oyster; Genetic. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/acte-3451.pdf |
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| Boudry, Pierre; Chatain, Beatrice; Naciri-graven, Yamama; Lemaire, Christophe; Gerard, Andre. |
| In France, marine fish and shellfish farming is based mainly on the breeding of wild species, whose natural populations are traditionally exploited. Research programs are conducted by IFREMER, in co-operation with INRA and Universities. French research programs for the genetical improvement of marine fish and shellfish concern primarily seabass (Dicentrarchus labrax) and oysters (Ostrea edulis and Crassostrea gigas). The following programs are developed: The knowledge of wild and farmed populations. The most recent prodjects involve the highly variable microsatellite markers. Seven markers are presently available for seabass and the work is now initiated on turbot (Scophthalmus maximus). In molluscs, microsatellite markers have been developed for the... |
| Tipo: Text |
Palavras-chave: Selection; Triploid; Shellfish; Fish; Genetic. |
| Ano: 1996 |
URL: http://archimer.ifremer.fr/doc/1996/acte-3206.pdf |
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| Boudry, Pierre; Collet, Bertrand; Cornette, Florence; Hervouet, Veronique; Bonhomme, Francois. |
| Oysters, like many marine species have a very high fecundity. Previous studies have shown that populations, from both hatcheries and the natural environment, have very low Ne/N ratios. These observations reveal high variation in reproductive success. In order to study individual reproductive success under controlled conditions, we used microsatellite markers to quantify parental contributions in in vitro crosses (5 males and 5 females) of Crassostrea gigas, the Pacific oyster. High polymorphism of the microsatellites (more that 50 alleles per locus) eased the parentage identifications. The results of a cross allowing gametic competition were compared with the results from a second cross where the gametes of the same parents were kept separate for each... |
| Tipo: Text |
Palavras-chave: Genetic; Hatchery; Microsatellite markers; Crassostrea gigas; Pacific oysters. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/acte-3457.pdf |
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| Boudry, Pierre; Degremont, Lionel; Bedier, Edouard; Pouvreau, Stephane; Normand, Julien; Ernande, Bruno. |
| To date, the most significant method to genetically reduce reproductive effort in the Pacific oyster (Crassostrea gigas) has been through the production of triploids, especially since the development of tetraploid lines allowing the breeding of 'natural' triploids. Gametogenesis of triploid oysters is strongly reduced compared with diploids, although they are not fully sterile and can produce viable gametes and some progenies when crossed with diploids. Reduced reproductive allocation and higher heterozygocity are commonly proposed as the main reasons why triploids often present superior yield compared with diploids. Temperature and food availability are known to favour gametogenesis in triploids, but the existence of genetic variation for this trait... |
| Tipo: Text |
Palavras-chave: Selective breeding; Reproduction; Genetic variation; Crassostrea gigas; Pacific oyster; Genetic. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/acte-3445.pdf |
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| Boudry, Pierre; Degremont, Lionel; Taris, Nicolas; Mccombie, Helen; Haffray, Pierrick; Ernande, Bruno. |
| To date, the most significant genetic improvement for the production of Pacific oyster (Crassostrea gigas) has been obtained through the breeding of triploids, especially since the development of tetraploids. Quantitative genetics studies suggest that significant gains, for disease resistance or for other traits of aquacultural interest, could be obtained in diploids using this approach. However, the limited extent of hatchery-propagation (versus natural recruitment) and/or various technical difficulties and biological characteristics of the species have retarded the development of selective breeding programs. Recently, in the U.S.A., Australia and New Zealand, countries where hatcheries are a major source of C. gigas juveniles, family-based selective... |
| Tipo: Text |
Palavras-chave: Microsatellite markers; Selective breeding; Genetic; Genetic variability; Crassostrea gigas; Pacific oysters. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/acte-3449.pdf |
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| Boudry, Pierre; Haffray, Pierrick. |
| The most significant genetic improvement for the production of Pacific oyster (Crassostrea gigas) in France to date has been through the breeding of triploids, especially since the development of tetraploids. Triploid oysters commonly resist summer mortality better than diploids. This is most probably because reproductive allocation is so important in this phenomenon. Quantitative genetics studies strongly suggest that a significant gain in resistance to summer mortality, or other traits of interest, could be obtained by selective breeding. Practical difficulties however, and the high cost of breeding large numbers of families under common conditions over many generations remain major constraints to family-based selective breeding in oysters. In the last... |
| Tipo: Text |
Palavras-chave: Polyploidization; Selective breeding; Genetic; Crassostrea gigas; Pacific oysters. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/acte-3438.pdf |
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| Boudry, Pierre; Huvet, Arnaud. |
| The taxonomic status of Crassostrea angulata and Crassostrea gigas has long been a matter of controversy. Morphological and physiological similarities, as well as homogeneity in allelic frequencies on allozymes between the populations of the two taxa, lead most authors to suggest to regroup of the two within the same species. European and Asian populations of C. gigas and C. angulata have been studied using microsatellite and mitochondrial DNA markers. The analysis of genetic distances and the distribution of allelic and haplotype frequencies revealed a differentiation between the populations of C. gigas and C. angulata. The data allowed the construction of Neighbor-joining trees for each of the two types of markers. Similar topologies appeared with data... |
| Tipo: Text |
Palavras-chave: Mitochondrial DNA; Nuclear DNA; Phylogeography; Crassostrea angulata; Crassostrea gigas; Genetic; Oyster. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/1999/acte-3434.pdf |
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| Boudry, Pierre; Huvet, Arnaud; Fabioux, Caroline; Lapegue, Sylvie. |
| Crassostrea angulata and Crassostrea gigas, two cupped oyster taxa of Asian origin (O'Foighil et al, 1998), were successively introduced into Europe during the XVIth and the XXth century respectively (Héral and Grizel, 1991). To date, populations presumed to be C. angulata remain only in the south of Spain and Portugal, while the geographic range of C. gigas is expending, notably due to aquaculture. The two taxa can be distinguished by RFLP analysis of the mitochondrial Cytochrome Oxydase I locus (COI). This marker revealed strong genetic differentiation between Asian populations of the two taxa (Boudry et al., 1998). In contrast, nuclear markers showed a much lower genetic differentiation (Huvet et al, in press). The absence of any reproductive barrier... |
| Tipo: Text |
Palavras-chave: Microsatellite; Genetic; Crassostrea angulata; Crassostrea gigas; Oysters. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/acte-3453.pdf |
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| Registros recuperados: 97 | |
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