Claire Baril - Academia.edu (original) (raw)

Papers by Claire Baril

Research paper thumbnail of Selection of environments using simultaneous clustering based on genotype × environment interaction

Canadian Journal of Plant Science, Apr 1, 1994

Cluster analysis is used to classify genotypes and environments to decompose and interpret genoty... more Cluster analysis is used to classify genotypes and environments to decompose and interpret genotype × environment (GE) interaction. A simultaneous clustering method is applied to wheat-yield data collected over 8 yr in seven locations, with two agronomic treatments per location. This approach evidenced redundancies among the used environments constituting the Institut National de la Recherche Agronomique series of experiments in northern France. The aim is to reduce the number of environments without losing GE interaction. A graphical method based on the decreasing mean square of GE interaction is proposed to provide a cutting criterion of the cluster procedure. The comparison of groupings made independently for successive years suggested the removal of some environments, hence providing rational savings in the breeding program. Lastly, the simultaneous two-way clustering procedure is compared with the common one-way clustering procedure. Key words: Cluster analysis, genotype × environment interaction, pattern analysis, series of experiments, wheat

Research paper thumbnail of Analysing genotype by environment interaction in Dutch potato variety trials using factorial regression

Euphytica, 1995

Genotype by environment interaction was investigated for yield data from the official Dutch Varie... more Genotype by environment interaction was investigated for yield data from the official Dutch Variety List trials for potato. The data set included 64 genotypes by 26 environments, where environments consisted of year by soil type combinations. Factorial regression models incorporating genotypic and environmental covariates in the interaction were used to analyse the data. The merits of factorial regression models 'were compared with those of biadditive models. Factorial regression models and biadditive models described comparable amounts of interaction, but factorial regression models provided a better basis for biological interpretation of the interaction.

Research paper thumbnail of Interpretation of genotype by environment interaction in two sunflower experimental networks

Theoretical and Applied Genetics, Feb 1, 2001

Genotype by environment interaction was investigated for sunflower grain yield in French official... more Genotype by environment interaction was investigated for sunflower grain yield in French official trials from two different networks. Genotype by environment interaction was described using cross-product terms from factorial regression. This modelling provided parsimonious descriptions of interaction: up to 20% of the sum of squares of interaction was explained using less than 7% of the degrees of freedom. It also made biological interpretation easier. Genotypic earliness at flowering by environmental earliness, and genotypic oil content by water deficit during the flowering period, appeared to be two repeatable interactions: in both data sets, early genotypes performed better in early environments while late genotypes gave much better yields in late environments, and the yield advantage of low-oil genotypes over high-oil genotypes was larger when water supply during flowering was non-limiting than in the case of water stress. Combined analysis of both data sets allowed us to compare patterns of interaction in both networks and to select a more robust model.

Research paper thumbnail of Genetic Distance Estimators Based on Molecular Data for Plant Registration and Protection: A Review

Acta horticulturae, Feb 1, 2001

As the number of varieties continuously increases, the discrimination among cultivars based on mo... more As the number of varieties continuously increases, the discrimination among cultivars based on morphological traits becomes more and more difficult to achieve in the context of plant registration. Molecular markers can be used as a complementary tool and a convenient way to combine the information from a large number of markers is to use estimators of distance. The aim of this paper was to review suitable estimators for computing genetic distances between cultivars in the context of the plant registration and protection. The estimators were classified according to the varietal structure of the cultivars (homogeneous vs. heterogeneous varieties) and the type of molecular data (allelic vs. banding data). Their statistical properties such as their sampling variance and their distribution were presented. The basis of potential statistical tests to deal with distinctness and essential derivation were discussed. Finally, a software package developed to estimate pairwise distances among cultivars from a collection and to analyse genetic diversity was described.

Research paper thumbnail of Evolution de la variance génétique additive dans une population soumise à sélection

L'etude simultanee de l'evolution de la variance genetique additive et des desequilibres ... more L'etude simultanee de l'evolution de la variance genetique additive et des desequilibres de liaison dans une population soumise a selection constitue une approche originale qui autorise l'introduction des processus d'evolution dans le modele de genetique quantitative. Grâce a la prise en compte de la structuration intra et inter individuelle, l'equation de recurrence de la variance additive fait apparaitre un taux de variance gardee en reserve par la recombinaison, un taux de variance dissipee par la derive et un coefficient traduisant l'effet de la selection. Cette nouvelle formalisation de l'evolution de la variance additive permet, dans certaines conditions, de mettre en evidence de facon analytique des " remontees " de variance au cours du processus de selection

Research paper thumbnail of Prediction of Euclidean distances with discrete and continuous outcomes

Journal of Multivariate Analysis, Sep 1, 2006

The objective of this paper is first to predict generalized Euclidean distances in the context of... more The objective of this paper is first to predict generalized Euclidean distances in the context of discrete and quantitative variables and then to derive their statistical properties. We first consider the simultaneous modelling of discrete and continuous random variables with covariates and obtain the likelihood. We derive an important property useful for its practical maximization. We then study the prediction of any Euclidean distances and its statistical proprieties, especially for the Mahalanobis distance. The quality of distance estimation is analyzed through simulations. This results are applied to our motivating example: the official distinction procedure of rapeseed varieties.

Research paper thumbnail of User's manual for the Lcdmv software (calculation software of molecular distances between varieties) for fingerprinting and genetic diversity studies

CIMMYT, México, 2003

User's Manual for the LCDMV Software (Calculation Software of Molecular Distances between Va... more User's Manual for the LCDMV Software (Calculation Software of Molecular Distances between Varieties). For Fingerprinting and Genetic Diversity Studies Dubreuil, P. ; Dillman, C. ; Warburton, Marilyn ; Crossa, Jose L. ; Franco, Jorge ; Baril, C. ... Data Analysis in the ...

Research paper thumbnail of Proceedings of the International Symposium on Molecular Markers for Characterizing Genotypes and Identifying Cultivars in Horticulture, Montpellier, France, 6-8 March 2000

International Society for Horticultural Science eBooks, 2001

Research paper thumbnail of Estimation de la proximite genetique de varietes de colza sur la base de marqueurs moleculaires : consequences pour l'inscription et la protection varietale

L'inscription et la protection des varietes de colza ne reposent actuellement que sur l'o... more L'inscription et la protection des varietes de colza ne reposent actuellement que sur l'observation de 13 caracteres morpho-physiologiques dont l'expression est influencee par l'environnement et sur l'utilisation de sept systemes isoenzymatiques peu polymorphes. La description des varietes avec ces seuls caracteres devient insuffisamment pertinente en raison de l'augmentation du nombre d'etudes. L'objectif de ce travail est de montrer les potentialites des marqueurs moleculaires comme nouveaux descripteurs. Dans le cadre de la protection varietale, les marqueurs permettent une estimation de l'apparentement des varietes pour instruire les cas de derivation essentielle. La cartographie de marqueurs aflp sur trois populations a permis de construire la premiere carte genetique consensus saturee du colza. L'utilisation de cette information dans le calcul d'une distance genetique a conduit a une amelioration de 25% de l'ecart-type de l'e...

Research paper thumbnail of Metamorphic rate in Rana pipiens larvae treated with thyroxine or prolactin at different times in the light/dark cycle

General and Comparative Endocrinology, 1986

Rana pipiens tadpoles at Stages V to VIIK on a 12Li12D cycle with photoperiod from 0800 to 2000 h... more Rana pipiens tadpoles at Stages V to VIIK on a 12Li12D cycle with photoperiod from 0800 to 2000 hr were treated with 30 pg/liter thyroxine (T4) by immersion for various daily 8-hr spans, or by daily intraperitoneal injection at different times with 0.1 to 10 bg T, or 10 Kg prolactin (PRL), in order to see if the rate of metamorphosis varied with the time of hormone treatment. T, was most effective in promoting tail resorption and hindlimb growth and development if tadpoles were immersed at least partly in the light or if the hormone was injected late in the dark or in the early or mid light phase. T4 was least effective in accelerating metamorphosis when immersion was totally in the dark or injection early in the dark. PRL antagonized metamorphosis just as well at any time of the day except that tail fin growth was faster when PRL was administered earty in the dark. The findings show circadian vacations in target tissue responsiveness to exogenous T4 that depend on the occurrence of light during T, immersion or following T, injection. The data 'suggest rhythmicity in the secretion of endogenous T4 in the tadpole and a diurnal eff&t on T, utilization by target cells. 0 1986 Academic Press. Inc.

Research paper thumbnail of De la génétique des populations à la génétique quantitative

LA GÉNÉTIQUE QUANTITATIVE 7.1 Modèle infinitésimal et approche Gaussienne 7.2 Lien avec le théorè... more LA GÉNÉTIQUE QUANTITATIVE 7.1 Modèle infinitésimal et approche Gaussienne 7.2 Lien avec le théorème de Fisher (Charnov 1989) 36 7.3 Généralisation aux cas d 'appariements préférentiels 8. FORMALISATION DE TURELLI ET BARTON 42 ANNEXES QUELQUES OUVRAGES DE RÉFÉRENCE Au commencement était MENDEL ruminant ses pensées solitaires. Puis il dit : "Q u'il y ait des pois", et il leur dit : ''Croissez et multipliez, différenciez-vous et assortissez-vous indépendamment". Ainsi firent-ils, et cela était bon. Puis advint que MENDEL rassem bla ses pois et les sépara en graines rondes et ridées; il appela les rondes dominantes, et les ridées récessives, et cela était bon. Mais MENDEL vit alors qu'il y avait 450 pois ronds et, 102 pois ridés. Cela n 'était pas bon. Car la loi stipule qu'il doit y avoir trois ronds pour un ridé. Et MENDEL se dit en lui-même: "Gott in Himmel, c 'est là l'oeuvre d 'un ennemi qui aura semé des mauvais pois dans mon jardin à la faveur de la nuit". Et MENDEL pris d 'un juste courroux, frappa sur la table et dit: "Eloignez-vous de moi, pois maudits et diaboliques, retournez dans ces ténèbres où vous serez dévorés par les rats et les souris!"Et il en fut ainsi; il ne resta plus que 300 pois ronds et 100 pois ridés, et. cela était bon. Excellent même. Et MENDEL le publia.

Research paper thumbnail of Predicting phenotypic distances using a linear model : the case of varietal distinctness

Research paper thumbnail of Etude de la stabilité de l'ACP par la méthode du bootstrap

Research paper thumbnail of Les marqueurs moléculaires : un nouvel outil pour l'inscription et la protection variétale ? : Aspects des filières semencières Nord/Sud

The use of molecular markers for the registration of new varieties and for the protection of plan... more The use of molecular markers for the registration of new varieties and for the protection of plant breeders has been analysed in many research studies and widely discussed among the international seeds community. Before adopting these powerful varietal characterisation tools, the underlying methods and techniques used remain to be defined.

Research paper thumbnail of Fine-Scale Spatial Genetic Structure with Nonuniform Distribution of Individuals

Genetics, 1998

This paper presents the first theoretical study of spatial genetic structure within nonuniformly ... more This paper presents the first theoretical study of spatial genetic structure within nonuniformly distributed continuous plant populations. A novel individual-based model of isolation by distance was constructed to simulate genetic evolution within such populations. We found larger values of spatial genetic autocorrelations in highly clumped populations than in uniformly distributed populations. Most of this difference was caused by differences in mean dispersal distances, but aggregation probably also produced a slight increase in spatial genetic structure. Using an appropriate level of approximation of the continuous distribution of individuals in space, we assessed the potential effects of density, seed and pollen dispersal, generation overlapping, and overdominance selection at an independent locus, on fine-scale genetic structure, by varying them separately in a few particular cases with extreme clumping. When selfing was allowed, all these input variables influenced both aggreg...

Research paper thumbnail of Etude de la stabilite du rendement chez le ble tendre d'hiver (triticum aestivum l. Thell. )

Http Www Theses Fr, 1992

L'analyse d'un ensemble de 280 lignees de ble tendre d'hiver, experimentees au sein d... more L'analyse d'un ensemble de 280 lignees de ble tendre d'hiver, experimentees au sein du reseau inter-stations de l'inra, comprenant 106 milieux differents a permis d'etudier les interactions genotype x milieu observees sur le rendement. Ces interactions representent, selon les annees d'experimentation, entre 13 et 46 pourcent de la variabilite phenotypique globale. La mise au point d'une methode d'utilisation de caracteres auxiliaires, couramment mesures dans les essais, permet, grace aux modeles de regression factorielle, d'expliquer 73 pourcent de l'interaction en termes biologiques, soit 91 pourcent de la variation du rendement. De plus, trois methodes de determination du nombre minimum de milieux d'experimentations sont proposees afin d'optimiser le reseau multilocal et pluriannuel etudie. Une restructuration de ce reseau est envisagee. La multiplicite des origines de selection a permis d'etudier l'influence des sites de selection sur les parametres de stabilite du rendement. Une selection indirecte pour une certaine robustesse, realisee dans des milieux revelant peu de facteurs limitants, ne permet pas d'obtenir des genotypes aussi stables que ceux issus d'une selection directe, pratiquee en presence de facteurs limitants. Par ailleurs, l'influence de la precocite d'epiaison sur la stabilite du rendement est soulignee. Une part importante de l'interaction provient, en effet, d'une trop grande tardivete de certains genotypes lorsqu'ils sont experimentes dans des milieux favorisant des cycles de developpement courts. Enfin, l'interet d'une selection multilocale pour l'obtention de genotypes stables et performants est mis en evidence

Research paper thumbnail of Structure spatiale g�n�tique et niveau de diversit� intrapopulation chez les arbres forestiers

Gse, 1998

Spatial genetic structure and diversity within forest tree populations. An isolation by distance ... more Spatial genetic structure and diversity within forest tree populations. An isolation by distance model is presented, which is better fitted to forest tree populations than those available to date. This model was developed in order to understand which factors might determine genetic diversity and spatial structure within populations of these species, for in situ management of their genetic resources. It allows a nonuniform spatial distribution of individuals, as well as some selfing. This model was studied by means of simulations, using a complete factorial design with 32 highly contrasted cases, which resulted from the combination of different values of the following input variables: global density, seed and pollen dispersal distances, generation overlap and overdominant selection. Our results show that much of the variation in spatial genetic structure and inbreeding at the individual level can be explained by variations in clumping and outcrossing rate. Inbreeding at the population level is mainly determined by the degree of generation overlap. As a general conclusion, all the input variables studied here do affect the genetic characteristics of simulated populations, and most interaction effects between these variables are highly significant. These results suggest that the explanation of differences in the level and/or structure of within-population genetic diversity between tree species could presumably be improved by using additional classification factors such as density, the level of clumping, generation overlapping, and/or selection, as well as by taking into account the interaction effects between classification factors. © Inra/Elsevier, Paris isolation by distance / forest tree / model / genetic diversity / spatial genetic structure Résumé-Nous avons développé un modèle d'isolement par la distance adapté aux populations d'arbres forestiers, afin de comprendre les facteurs qui déterminent la structure spatiale génétique et le niveau de diversité intrapopulation chez ces espèces, en vue de la gestion in situ de leurs ressources génétiques. Il permet de prendre en compte une répartition spatiale non uniforme des individus. On a étudié par * Correspondance et tirés à part

Research paper thumbnail of Conceptual and Statistical Issues Related to the Use of Molecular Markers for Distinctness and Essential Derivation

Acta Horticulturae, 2001

An exhibition is given of old and new statistical procedures for dealing with marker information ... more An exhibition is given of old and new statistical procedures for dealing with marker information in the context of distinctness testing and assessing genetic conformity for essential derivation purposes. Conceptual issues are discussed in relation to statistical methods. It is believed that the most important statistical and conceptual difference between distinctness and conformity testing resides in the wording of null and alternative hypotheses. For distinctness testing, the null hypothesis states no difference between varieties, while the alternative implies the existence of a difference. For conformity testing, null and alternative hypothesis are non-equivalence and equivalence, respectively. The reversal of null and alternative hypothesis has rather limited statistical consequences when test statistics are distance measures. Characteristically, morphological characters form the preferred traits for assessing distinctness, while molecular markers are chosen for assessing conformity. From a statistical point of view this difference is rather immaterial. Distinctness and conformity are throughout presented as two closely related concepts, whose assessment takes place by highly comparable statistical procedures. Specific topics that are addressed in the paper are first the present positions of UPOV and ASSINSEL. Subsequently, uni-and multivariate methods for distinctness and conformity are treated, separately for genetically homogeneous and heterogeneous varieties. Lastly, the choice of markers is discussed, as are the relations between morphological, marker and pedigree information.

Research paper thumbnail of Varietal Distinctness Assisted by Molecular Markers: A Methodological Approach

Acta Horticulturae, 2001

The varietal distinctness procedure involves expensive, space and time consuming measurements of ... more The varietal distinctness procedure involves expensive, space and time consuming measurements of phenotypical traits. Moreover, for most species and traits, interactions between genotype and environment complicate the cultivar evaluation. Molecular markers could provide a distinctness procedure that actually help increasing reliability of decisions and saving field experiments and time. In the statistical framework of the linear model, the authors propose to define a new distinctness procedure using molecular data to predict phenotypical distance between cultivars. As an example, this method is applied to maize data and leads to 29% of savings for less than 5% of errors. Improvement of these methods are finally discussed. 1.

Research paper thumbnail of CARACTERISATION VARIETALE Les marqueurs moléculaires : un nouvel outil pour l’inscription et la protection variétale ?

Oléagineux, Corps gras, Lipides, 2001

Le Geves (Groupe d'étude et de contrôle des variétés et des semences) a pour mission officielle d... more Le Geves (Groupe d'étude et de contrôle des variétés et des semences) a pour mission officielle de mener les études nécessaires à l'homologation des variétés végétales nouvelles, la protection juridique du droit des obtenteurs et la certification des semences avant leur commercialisation, dans le cas des espèces soumises à une certification réglementaire. L'inscription d'une variété nouvelle au catalogue officiel est une condition nécessaire à sa commercialisation. Pour être homologuée, une variété doit être distincte, homogène et stable (DHS) et apporter un progrès au niveau de sa valeur agronomique ou technologique (VAT). L'expertise des nouvelles variétés est effectuée pour le compte du CTPS (Comité technique permanent de la sélection), placé sous l'autorité du ministère de l'Agriculture. Le matériel végétal nouveau peut bénéficier d'une protection légale par la délivrance d'un certificat d'obtention végétale (COV) par le CPOV (Comité de protection des obtentions végétales), en application de la convention internationale de l'Upov (Union pour la protection des obtentions végétales). La protection juridique du droit de l'obtenteur permet la valorisation de l'innovation variétale et, donc, celle des investissements de recherche. La production de semences certifiées suit des protocoles et respecte des normes de qualité très précises. Avant leur commercialisation, tous les lots de semences d'espèces certifiables sont échantillonnés et analysés. Les contrôles d'identité et de pureté variétale ainsi que les analyses de qualité des semences sont réalisés à la demande du SOC (Service officiel de contrôle et de certification), service technique du GNIS (Groupement national interprofessionnel des semences). Summary : The use of molecular markers for the registration of new varieties and for the protection of plant breeders has been analysed in many research studies and widely discussed among the international seeds community. Before adopting these powerful varietal characterisation tools, the underlying methods and techniques used remain to be defined.

Research paper thumbnail of Selection of environments using simultaneous clustering based on genotype × environment interaction

Canadian Journal of Plant Science, Apr 1, 1994

Cluster analysis is used to classify genotypes and environments to decompose and interpret genoty... more Cluster analysis is used to classify genotypes and environments to decompose and interpret genotype × environment (GE) interaction. A simultaneous clustering method is applied to wheat-yield data collected over 8 yr in seven locations, with two agronomic treatments per location. This approach evidenced redundancies among the used environments constituting the Institut National de la Recherche Agronomique series of experiments in northern France. The aim is to reduce the number of environments without losing GE interaction. A graphical method based on the decreasing mean square of GE interaction is proposed to provide a cutting criterion of the cluster procedure. The comparison of groupings made independently for successive years suggested the removal of some environments, hence providing rational savings in the breeding program. Lastly, the simultaneous two-way clustering procedure is compared with the common one-way clustering procedure. Key words: Cluster analysis, genotype × environment interaction, pattern analysis, series of experiments, wheat

Research paper thumbnail of Analysing genotype by environment interaction in Dutch potato variety trials using factorial regression

Euphytica, 1995

Genotype by environment interaction was investigated for yield data from the official Dutch Varie... more Genotype by environment interaction was investigated for yield data from the official Dutch Variety List trials for potato. The data set included 64 genotypes by 26 environments, where environments consisted of year by soil type combinations. Factorial regression models incorporating genotypic and environmental covariates in the interaction were used to analyse the data. The merits of factorial regression models 'were compared with those of biadditive models. Factorial regression models and biadditive models described comparable amounts of interaction, but factorial regression models provided a better basis for biological interpretation of the interaction.

Research paper thumbnail of Interpretation of genotype by environment interaction in two sunflower experimental networks

Theoretical and Applied Genetics, Feb 1, 2001

Genotype by environment interaction was investigated for sunflower grain yield in French official... more Genotype by environment interaction was investigated for sunflower grain yield in French official trials from two different networks. Genotype by environment interaction was described using cross-product terms from factorial regression. This modelling provided parsimonious descriptions of interaction: up to 20% of the sum of squares of interaction was explained using less than 7% of the degrees of freedom. It also made biological interpretation easier. Genotypic earliness at flowering by environmental earliness, and genotypic oil content by water deficit during the flowering period, appeared to be two repeatable interactions: in both data sets, early genotypes performed better in early environments while late genotypes gave much better yields in late environments, and the yield advantage of low-oil genotypes over high-oil genotypes was larger when water supply during flowering was non-limiting than in the case of water stress. Combined analysis of both data sets allowed us to compare patterns of interaction in both networks and to select a more robust model.

Research paper thumbnail of Genetic Distance Estimators Based on Molecular Data for Plant Registration and Protection: A Review

Acta horticulturae, Feb 1, 2001

As the number of varieties continuously increases, the discrimination among cultivars based on mo... more As the number of varieties continuously increases, the discrimination among cultivars based on morphological traits becomes more and more difficult to achieve in the context of plant registration. Molecular markers can be used as a complementary tool and a convenient way to combine the information from a large number of markers is to use estimators of distance. The aim of this paper was to review suitable estimators for computing genetic distances between cultivars in the context of the plant registration and protection. The estimators were classified according to the varietal structure of the cultivars (homogeneous vs. heterogeneous varieties) and the type of molecular data (allelic vs. banding data). Their statistical properties such as their sampling variance and their distribution were presented. The basis of potential statistical tests to deal with distinctness and essential derivation were discussed. Finally, a software package developed to estimate pairwise distances among cultivars from a collection and to analyse genetic diversity was described.

Research paper thumbnail of Evolution de la variance génétique additive dans une population soumise à sélection

L'etude simultanee de l'evolution de la variance genetique additive et des desequilibres ... more L'etude simultanee de l'evolution de la variance genetique additive et des desequilibres de liaison dans une population soumise a selection constitue une approche originale qui autorise l'introduction des processus d'evolution dans le modele de genetique quantitative. Grâce a la prise en compte de la structuration intra et inter individuelle, l'equation de recurrence de la variance additive fait apparaitre un taux de variance gardee en reserve par la recombinaison, un taux de variance dissipee par la derive et un coefficient traduisant l'effet de la selection. Cette nouvelle formalisation de l'evolution de la variance additive permet, dans certaines conditions, de mettre en evidence de facon analytique des " remontees " de variance au cours du processus de selection

Research paper thumbnail of Prediction of Euclidean distances with discrete and continuous outcomes

Journal of Multivariate Analysis, Sep 1, 2006

The objective of this paper is first to predict generalized Euclidean distances in the context of... more The objective of this paper is first to predict generalized Euclidean distances in the context of discrete and quantitative variables and then to derive their statistical properties. We first consider the simultaneous modelling of discrete and continuous random variables with covariates and obtain the likelihood. We derive an important property useful for its practical maximization. We then study the prediction of any Euclidean distances and its statistical proprieties, especially for the Mahalanobis distance. The quality of distance estimation is analyzed through simulations. This results are applied to our motivating example: the official distinction procedure of rapeseed varieties.

Research paper thumbnail of User's manual for the Lcdmv software (calculation software of molecular distances between varieties) for fingerprinting and genetic diversity studies

CIMMYT, México, 2003

User's Manual for the LCDMV Software (Calculation Software of Molecular Distances between Va... more User's Manual for the LCDMV Software (Calculation Software of Molecular Distances between Varieties). For Fingerprinting and Genetic Diversity Studies Dubreuil, P. ; Dillman, C. ; Warburton, Marilyn ; Crossa, Jose L. ; Franco, Jorge ; Baril, C. ... Data Analysis in the ...

Research paper thumbnail of Proceedings of the International Symposium on Molecular Markers for Characterizing Genotypes and Identifying Cultivars in Horticulture, Montpellier, France, 6-8 March 2000

International Society for Horticultural Science eBooks, 2001

Research paper thumbnail of Estimation de la proximite genetique de varietes de colza sur la base de marqueurs moleculaires : consequences pour l'inscription et la protection varietale

L'inscription et la protection des varietes de colza ne reposent actuellement que sur l'o... more L'inscription et la protection des varietes de colza ne reposent actuellement que sur l'observation de 13 caracteres morpho-physiologiques dont l'expression est influencee par l'environnement et sur l'utilisation de sept systemes isoenzymatiques peu polymorphes. La description des varietes avec ces seuls caracteres devient insuffisamment pertinente en raison de l'augmentation du nombre d'etudes. L'objectif de ce travail est de montrer les potentialites des marqueurs moleculaires comme nouveaux descripteurs. Dans le cadre de la protection varietale, les marqueurs permettent une estimation de l'apparentement des varietes pour instruire les cas de derivation essentielle. La cartographie de marqueurs aflp sur trois populations a permis de construire la premiere carte genetique consensus saturee du colza. L'utilisation de cette information dans le calcul d'une distance genetique a conduit a une amelioration de 25% de l'ecart-type de l'e...

Research paper thumbnail of Metamorphic rate in Rana pipiens larvae treated with thyroxine or prolactin at different times in the light/dark cycle

General and Comparative Endocrinology, 1986

Rana pipiens tadpoles at Stages V to VIIK on a 12Li12D cycle with photoperiod from 0800 to 2000 h... more Rana pipiens tadpoles at Stages V to VIIK on a 12Li12D cycle with photoperiod from 0800 to 2000 hr were treated with 30 pg/liter thyroxine (T4) by immersion for various daily 8-hr spans, or by daily intraperitoneal injection at different times with 0.1 to 10 bg T, or 10 Kg prolactin (PRL), in order to see if the rate of metamorphosis varied with the time of hormone treatment. T, was most effective in promoting tail resorption and hindlimb growth and development if tadpoles were immersed at least partly in the light or if the hormone was injected late in the dark or in the early or mid light phase. T4 was least effective in accelerating metamorphosis when immersion was totally in the dark or injection early in the dark. PRL antagonized metamorphosis just as well at any time of the day except that tail fin growth was faster when PRL was administered earty in the dark. The findings show circadian vacations in target tissue responsiveness to exogenous T4 that depend on the occurrence of light during T, immersion or following T, injection. The data 'suggest rhythmicity in the secretion of endogenous T4 in the tadpole and a diurnal eff&t on T, utilization by target cells. 0 1986 Academic Press. Inc.

Research paper thumbnail of De la génétique des populations à la génétique quantitative

LA GÉNÉTIQUE QUANTITATIVE 7.1 Modèle infinitésimal et approche Gaussienne 7.2 Lien avec le théorè... more LA GÉNÉTIQUE QUANTITATIVE 7.1 Modèle infinitésimal et approche Gaussienne 7.2 Lien avec le théorème de Fisher (Charnov 1989) 36 7.3 Généralisation aux cas d 'appariements préférentiels 8. FORMALISATION DE TURELLI ET BARTON 42 ANNEXES QUELQUES OUVRAGES DE RÉFÉRENCE Au commencement était MENDEL ruminant ses pensées solitaires. Puis il dit : "Q u'il y ait des pois", et il leur dit : ''Croissez et multipliez, différenciez-vous et assortissez-vous indépendamment". Ainsi firent-ils, et cela était bon. Puis advint que MENDEL rassem bla ses pois et les sépara en graines rondes et ridées; il appela les rondes dominantes, et les ridées récessives, et cela était bon. Mais MENDEL vit alors qu'il y avait 450 pois ronds et, 102 pois ridés. Cela n 'était pas bon. Car la loi stipule qu'il doit y avoir trois ronds pour un ridé. Et MENDEL se dit en lui-même: "Gott in Himmel, c 'est là l'oeuvre d 'un ennemi qui aura semé des mauvais pois dans mon jardin à la faveur de la nuit". Et MENDEL pris d 'un juste courroux, frappa sur la table et dit: "Eloignez-vous de moi, pois maudits et diaboliques, retournez dans ces ténèbres où vous serez dévorés par les rats et les souris!"Et il en fut ainsi; il ne resta plus que 300 pois ronds et 100 pois ridés, et. cela était bon. Excellent même. Et MENDEL le publia.

Research paper thumbnail of Predicting phenotypic distances using a linear model : the case of varietal distinctness

Research paper thumbnail of Etude de la stabilité de l'ACP par la méthode du bootstrap

Research paper thumbnail of Les marqueurs moléculaires : un nouvel outil pour l'inscription et la protection variétale ? : Aspects des filières semencières Nord/Sud

The use of molecular markers for the registration of new varieties and for the protection of plan... more The use of molecular markers for the registration of new varieties and for the protection of plant breeders has been analysed in many research studies and widely discussed among the international seeds community. Before adopting these powerful varietal characterisation tools, the underlying methods and techniques used remain to be defined.

Research paper thumbnail of Fine-Scale Spatial Genetic Structure with Nonuniform Distribution of Individuals

Genetics, 1998

This paper presents the first theoretical study of spatial genetic structure within nonuniformly ... more This paper presents the first theoretical study of spatial genetic structure within nonuniformly distributed continuous plant populations. A novel individual-based model of isolation by distance was constructed to simulate genetic evolution within such populations. We found larger values of spatial genetic autocorrelations in highly clumped populations than in uniformly distributed populations. Most of this difference was caused by differences in mean dispersal distances, but aggregation probably also produced a slight increase in spatial genetic structure. Using an appropriate level of approximation of the continuous distribution of individuals in space, we assessed the potential effects of density, seed and pollen dispersal, generation overlapping, and overdominance selection at an independent locus, on fine-scale genetic structure, by varying them separately in a few particular cases with extreme clumping. When selfing was allowed, all these input variables influenced both aggreg...

Research paper thumbnail of Etude de la stabilite du rendement chez le ble tendre d'hiver (triticum aestivum l. Thell. )

Http Www Theses Fr, 1992

L'analyse d'un ensemble de 280 lignees de ble tendre d'hiver, experimentees au sein d... more L'analyse d'un ensemble de 280 lignees de ble tendre d'hiver, experimentees au sein du reseau inter-stations de l'inra, comprenant 106 milieux differents a permis d'etudier les interactions genotype x milieu observees sur le rendement. Ces interactions representent, selon les annees d'experimentation, entre 13 et 46 pourcent de la variabilite phenotypique globale. La mise au point d'une methode d'utilisation de caracteres auxiliaires, couramment mesures dans les essais, permet, grace aux modeles de regression factorielle, d'expliquer 73 pourcent de l'interaction en termes biologiques, soit 91 pourcent de la variation du rendement. De plus, trois methodes de determination du nombre minimum de milieux d'experimentations sont proposees afin d'optimiser le reseau multilocal et pluriannuel etudie. Une restructuration de ce reseau est envisagee. La multiplicite des origines de selection a permis d'etudier l'influence des sites de selection sur les parametres de stabilite du rendement. Une selection indirecte pour une certaine robustesse, realisee dans des milieux revelant peu de facteurs limitants, ne permet pas d'obtenir des genotypes aussi stables que ceux issus d'une selection directe, pratiquee en presence de facteurs limitants. Par ailleurs, l'influence de la precocite d'epiaison sur la stabilite du rendement est soulignee. Une part importante de l'interaction provient, en effet, d'une trop grande tardivete de certains genotypes lorsqu'ils sont experimentes dans des milieux favorisant des cycles de developpement courts. Enfin, l'interet d'une selection multilocale pour l'obtention de genotypes stables et performants est mis en evidence

Research paper thumbnail of Structure spatiale g�n�tique et niveau de diversit� intrapopulation chez les arbres forestiers

Gse, 1998

Spatial genetic structure and diversity within forest tree populations. An isolation by distance ... more Spatial genetic structure and diversity within forest tree populations. An isolation by distance model is presented, which is better fitted to forest tree populations than those available to date. This model was developed in order to understand which factors might determine genetic diversity and spatial structure within populations of these species, for in situ management of their genetic resources. It allows a nonuniform spatial distribution of individuals, as well as some selfing. This model was studied by means of simulations, using a complete factorial design with 32 highly contrasted cases, which resulted from the combination of different values of the following input variables: global density, seed and pollen dispersal distances, generation overlap and overdominant selection. Our results show that much of the variation in spatial genetic structure and inbreeding at the individual level can be explained by variations in clumping and outcrossing rate. Inbreeding at the population level is mainly determined by the degree of generation overlap. As a general conclusion, all the input variables studied here do affect the genetic characteristics of simulated populations, and most interaction effects between these variables are highly significant. These results suggest that the explanation of differences in the level and/or structure of within-population genetic diversity between tree species could presumably be improved by using additional classification factors such as density, the level of clumping, generation overlapping, and/or selection, as well as by taking into account the interaction effects between classification factors. © Inra/Elsevier, Paris isolation by distance / forest tree / model / genetic diversity / spatial genetic structure Résumé-Nous avons développé un modèle d'isolement par la distance adapté aux populations d'arbres forestiers, afin de comprendre les facteurs qui déterminent la structure spatiale génétique et le niveau de diversité intrapopulation chez ces espèces, en vue de la gestion in situ de leurs ressources génétiques. Il permet de prendre en compte une répartition spatiale non uniforme des individus. On a étudié par * Correspondance et tirés à part

Research paper thumbnail of Conceptual and Statistical Issues Related to the Use of Molecular Markers for Distinctness and Essential Derivation

Acta Horticulturae, 2001

An exhibition is given of old and new statistical procedures for dealing with marker information ... more An exhibition is given of old and new statistical procedures for dealing with marker information in the context of distinctness testing and assessing genetic conformity for essential derivation purposes. Conceptual issues are discussed in relation to statistical methods. It is believed that the most important statistical and conceptual difference between distinctness and conformity testing resides in the wording of null and alternative hypotheses. For distinctness testing, the null hypothesis states no difference between varieties, while the alternative implies the existence of a difference. For conformity testing, null and alternative hypothesis are non-equivalence and equivalence, respectively. The reversal of null and alternative hypothesis has rather limited statistical consequences when test statistics are distance measures. Characteristically, morphological characters form the preferred traits for assessing distinctness, while molecular markers are chosen for assessing conformity. From a statistical point of view this difference is rather immaterial. Distinctness and conformity are throughout presented as two closely related concepts, whose assessment takes place by highly comparable statistical procedures. Specific topics that are addressed in the paper are first the present positions of UPOV and ASSINSEL. Subsequently, uni-and multivariate methods for distinctness and conformity are treated, separately for genetically homogeneous and heterogeneous varieties. Lastly, the choice of markers is discussed, as are the relations between morphological, marker and pedigree information.

Research paper thumbnail of Varietal Distinctness Assisted by Molecular Markers: A Methodological Approach

Acta Horticulturae, 2001

The varietal distinctness procedure involves expensive, space and time consuming measurements of ... more The varietal distinctness procedure involves expensive, space and time consuming measurements of phenotypical traits. Moreover, for most species and traits, interactions between genotype and environment complicate the cultivar evaluation. Molecular markers could provide a distinctness procedure that actually help increasing reliability of decisions and saving field experiments and time. In the statistical framework of the linear model, the authors propose to define a new distinctness procedure using molecular data to predict phenotypical distance between cultivars. As an example, this method is applied to maize data and leads to 29% of savings for less than 5% of errors. Improvement of these methods are finally discussed. 1.

Research paper thumbnail of CARACTERISATION VARIETALE Les marqueurs moléculaires : un nouvel outil pour l’inscription et la protection variétale ?

Oléagineux, Corps gras, Lipides, 2001

Le Geves (Groupe d'étude et de contrôle des variétés et des semences) a pour mission officielle d... more Le Geves (Groupe d'étude et de contrôle des variétés et des semences) a pour mission officielle de mener les études nécessaires à l'homologation des variétés végétales nouvelles, la protection juridique du droit des obtenteurs et la certification des semences avant leur commercialisation, dans le cas des espèces soumises à une certification réglementaire. L'inscription d'une variété nouvelle au catalogue officiel est une condition nécessaire à sa commercialisation. Pour être homologuée, une variété doit être distincte, homogène et stable (DHS) et apporter un progrès au niveau de sa valeur agronomique ou technologique (VAT). L'expertise des nouvelles variétés est effectuée pour le compte du CTPS (Comité technique permanent de la sélection), placé sous l'autorité du ministère de l'Agriculture. Le matériel végétal nouveau peut bénéficier d'une protection légale par la délivrance d'un certificat d'obtention végétale (COV) par le CPOV (Comité de protection des obtentions végétales), en application de la convention internationale de l'Upov (Union pour la protection des obtentions végétales). La protection juridique du droit de l'obtenteur permet la valorisation de l'innovation variétale et, donc, celle des investissements de recherche. La production de semences certifiées suit des protocoles et respecte des normes de qualité très précises. Avant leur commercialisation, tous les lots de semences d'espèces certifiables sont échantillonnés et analysés. Les contrôles d'identité et de pureté variétale ainsi que les analyses de qualité des semences sont réalisés à la demande du SOC (Service officiel de contrôle et de certification), service technique du GNIS (Groupement national interprofessionnel des semences). Summary : The use of molecular markers for the registration of new varieties and for the protection of plant breeders has been analysed in many research studies and widely discussed among the international seeds community. Before adopting these powerful varietal characterisation tools, the underlying methods and techniques used remain to be defined.