VARIABILITÉ PHÉNOTYPIQUE ET SÉLECTION DES CARACTÈRES AGRONOMIQUES DU BLÉ DUR (Triticum durum Desf.) SOUS CONDITIONS SEMI-ARIDES

Genetic improvement of agronomic traits related to yield performance and adaptation to the production environments is conditioned by the presence of phenotypic variability of the targeted characters in the plant material subjected to selection. This research was conducted to assess the magnitude of phenotypic variability, the heritability and the expected genetic gain of selection of agronomic traits in 18 durum wheat (Triticum durum Desf) varieties and segregating lines. The results showed the presence of significant variability for the measured traits. The degree of genetic determination had values greater than 70% for the duration of the vegetative phase and plant height, and below 50% for yield and aboveground biomass. The expected genetic gain ranged from 4.8% for the duration of the vegetative phase to 45.9% for grain yield. Single-character selection identified 6 desirable genotypes which brought increases of 14.9% in harvest index, 3.7 g in 1000 kernel weight, 4.8% in relative water content, and declines of 18.6% in percent cells injury, 2.1 g in yield per plant, 2.1 cm in spike length, and 12.9 grains per spike, and a gain of 1.7 spikes associated to 8.8 g of biomass. Relatively to Bousselam, the check cultivar, the selected lines brought a grain yield advantage ranging from 53.8 to 161.5%. This yield gain is associated with a desirable improvement in heat stress tolerance, and an undesirable reduction in thousand kernel weight. The study of th

DÉTERMINISME GÉNÉTIQUE DES CARACTÈRES MORPHO-PHYSIOLOGIQUES LIÉS AU RENDEMENT CHEZ LE BLÉ DUR EN ZONE SEMI-ARIDE DES HAUTS PLATEAUX SÉTIFIENS, ALGÉRIE

The present investigation was undertaken to study the inheritance pattern of morpho-physiological traits: relative water content, excised leaf water loss, flag leaf area and membrane stability, in an F3 population of durum wheat (Triticum durum Desf.). The results reflected a satisfactory range of variability in the evaluated traits. Range magnitude of the four traits represented the equivalent of 5.0 to 11.4 times the least significant difference at 5% level. Transgressors with variable frequency were observed for all the measured traits. In fact 25% of the F3 lines showed a relative water content greater than 85%, 3% has a flag leaf area superior to 26 cm², 8% had a low leaf water loss rate and 11% expressed a low electrolyte leakage rate, suggesting a high membrane stability. Medium to high broad sense heritability estimates were noted for the measured traits. Medium to high genetic gain expressed as percent of the base population mean was observed, taking the following values: 11.0%, 24.0%, 68% and 88%, for relative water content, flag leaf area, excised leaf water loss rate, and percent of cell injury, respectively. Altogether, the obtained results indicated that the studied cross population would be of interest in the breeding program and an effective progress can be made through selection of these morpho-physiological characters to enhance stress tolerance and grain yield potential

Analysis of the phenotypic variability of twenty f3 biparental populations of bread wheat (Triticum aestivum L.) evaluated under semi-arid environment

This research was conducted to screen and analyse the variability within twenty F3 populations of bread wheat (Triticum aestivum L.) generated by Line x Tester mating design. The results indicated the presence of sufficient variability within and between F3 populations for the eight measured variables, which represent plant phenology, physiology, yield and yield components. Different populations have been identified to improve the measured variables separately. The number of spikes appeared to be the most important determinant of grain yield. PCA and cluster analyses indicated that the Acsad1069/El Wifak and Acsad1135/Hidhab, with a relatively high grain yield,  aboveground biomass and 1000 grains weight, are the best F3 populations to improve the productivity. However, Acsad899/Rmada and Acsad1135/Rmada populations were earlier and had a low number of spikes. These populations had also favorable genes for heat tolerance.Keywords: Triticum aestivum L.; Variability; Selection; Tolerance; Yield

Analysis of the phenotypic variability of some varieties of durum wheat (Triticum durum Desf) to improve the efficiency of performance under the constraining conditions of semiarid environments

The experiment was conducted during three growing seasons and two planting dates. The cultivation site is placed at the ITGC Setif characterized by a semi-arid environment. The objective of the study is the analysis of phenotypic variability of traits measured for 15 varieties of durum wheat, through the average effects, to decline the ways, characters and varieties could play in favour of performance under the constraining semi-arid conditions. The year effect indicates that given the difficulty of predicting the performance enabled by years, it then makes sense to go straight for this performance within genotypes. Analysis of the effect genotype highlights characters connected to performance and is the Setifis variety that lends itself well. For the effect of sowing date, it is that early sowing promotes a better expression of the characteristics compared to late sowing.Keywords: Effect; genotype; year; date; variation; character

VARIABILITÉ PHÉNOTYPIQUE ET SÉLECTION DES CARACTÈRES AGRONOMIQUES DU BLÉ DUR (Triticum durum Desf.) SOUS CONDITIONS SEMI-ARIDES

Genetic improvement of agronomic traits related to yield performance and adaptation to the production environments is conditioned by the presence of phenotypic variability of the targeted characters in the plant material subjected to selection. This research was conducted to assess the magnitude of phenotypic variability, the heritability and the expected genetic gain of selection of agronomic traits in 18 durum wheat (Triticum durum Desf) varieties and segregating lines. The results showed the presence of significant variability for the measured traits. The degree of genetic determination had values greater than 70% for the duration of the vegetative phase and plant height, and below 50% for yield and aboveground biomass. The expected genetic gain ranged from 4.8% for the duration of the vegetative phase to 45.9% for grain yield. Single-character selection identified 6 desirable genotypes which brought increases of 14.9% in harvest index, 3.7 g in 1000 kernel weight, 4.8% in relative water content, and declines of 18.6% in percent cells injury, 2.1 g in yield per plant, 2.1 cm in spike length, and 12.9 grains per spike, and a gain of 1.7 spikes associated to 8.8 g of biomass. Relatively to Bousselam, the check cultivar, the selected lines brought a grain yield advantage ranging from 53.8 to 161.5%. This yield gain is associated with a desirable improvement in heat stress tolerance, and an undesirable reduction in thousand kernel weight. The study of th

DÉTERMINISME GÉNÉTIQUE DES CARACTÈRES MORPHO-PHYSIOLOGIQUES LIÉS AU RENDEMENT CHEZ LE BLÉ DUR EN ZONE SEMI-ARIDE DES HAUTS PLATEAUX SÉTIFIENS, ALGÉRIE

The present investigation was undertaken to study the inheritance pattern of morpho-physiological traits: relative water content, excised leaf water loss, flag leaf area and membrane stability, in an F3 population of durum wheat (Triticum durum Desf.). The results reflected a satisfactory range of variability in the evaluated traits. Range magnitude of the four traits represented the equivalent of 5.0 to 11.4 times the least significant difference at 5% level. Transgressors with variable frequency were observed for all the measured traits. In fact 25% of the F3 lines showed a relative water content greater than 85%, 3% has a flag leaf area superior to 26 cm², 8% had a low leaf water loss rate and 11% expressed a low electrolyte leakage rate, suggesting a high membrane stability. Medium to high broad sense heritability estimates were noted for the measured traits. Medium to high genetic gain expressed as percent of the base population mean was observed, taking the following values: 11.0%, 24.0%, 68% and 88%, for relative water content, flag leaf area, excised leaf water loss rate, and percent of cell injury, respectively. Altogether, the obtained results indicated that the studied cross population would be of interest in the breeding program and an effective progress can be made through selection of these morpho-physiological characters to enhance stress tolerance and grain yield potential

Respuesta del trigo duro (Triticum turgidum L. var. Durum) a la selección directa e indirecta en las condiciones semiáridas de Argelia

In arid and semi-arid areas, drought is an important abiotic factor that limits Durum wheat production. Identifying genotypes tolerant to drought is a challenge for plant breeders. This study aimed to evaluate the effect of direct and indirect selection on Durum wheat under rain-fed conditions in the high plains of Sétif, Algeria. Four parental varieties (Ofanto, MBB, Mrb5, Waha), three crosses (Ofanto/MBB, Ofanto/Mrb5, Ofanto/Waha) representing the F5, F6, and F7 populations, and one cultivar (Bousselm, control) were cultivated. Pheno-morpho-physiological traits were measured at the heading stage and yield and its components at grain maturity. Our results showed that the response to direct selection was reflected in a significant increase in grain yield, economic yield, and number of spikes, suggesting that grain yield may be improved using one of these characteristics as the selection criterion. Selection by canopy temperature was affected by a significant decrease in the drought susceptibility index (-11.3 %), making it possible to obtain abiotic stress-resistant lines. The study of the relationships between F5, F6, and F7 populations has shown that grain yield, economic yield, and plant height correlate with each generation, indicating no effect of genotype-environment interaction, unlike others. Late selection revealed eight meaningful lines (L1, L8, L14, L28, L32, L35, L36, and L40) in the selection process, maintaining high production throughout different cropping seasons. These successful lines were selected based on traits related to productivity: Gr.YLD, Ec.YLD, NS. These characters provide the same information as breeding programs, according to our results.En zonas áridas y semiáridas, la sequía es un factor abiótico que limita la producción de trigo duro; por tanto, la identificación de genotipos tolerantes a la sequía es un reto para los fitomejoradores. Este estudio buscó evaluar el efecto de la selección directa e indirecta en el trigo duro en condiciones de lluvia en las altas llanuras de Sétif, Argelia. Se cultivaron cuatro variedades parentales, tres cruces que representan las poblaciones F5, F6 y F7 y un cultivar (control). Los resultados mostraron que la respuesta a la selección directa se reflejó en un aumento significativo en el rendimiento del grano, el rendimiento económico y el número de espigas, lo que sugiere que es posible mejorar el rendimiento del grano utilizando una de estas características. La selección por temperatura del dosel se vio afectada por una disminución significativa del índice de susceptibilidad a la sequía (-11,3 %), lo que permite obtener líneas resistentes al estrés abiótico. El estudio de las relaciones entre las poblaciones F5, F6 y F7 ha mostrado que el rendimiento del grano, el rendimiento económico y la altura de la planta están correlacionados con estas generaciones, lo que indica que no se ven afectados por la interacción genotipo x ambiente, a diferencia de otros. La selección tardía reveló ocho líneas significativas, las cuales mantuvieron una alta producción en diferentes temporadas de cultivo. Estas líneas se seleccionaron con base en rasgos relacionados con la productividad que proporcionan la misma información que los programas de mejora, según nuestros resultados

Chronic Exposure to the Herbicide, Atrazine, Causes Mitochondrial Dysfunction and Insulin Resistance

There is an apparent overlap between areas in the USA where the herbicide, atrazine (ATZ), is heavily used and obesity-prevalence maps of people with a BMI over 30. Given that herbicides act on photosystem II of the thylakoid membrane of chloroplasts, which have a functional structure similar to mitochondria, we investigated whether chronic exposure to low concentrations of ATZ might cause obesity or insulin resistance by damaging mitochondrial function. Sprague-Dawley rats (n = 48) were treated for 5 months with low concentrations (30 or 300 µg kg−1 day−1) of ATZ provided in drinking water. One group of animals was fed a regular diet for the entire period, and another group of animals was fed a high-fat diet (40% fat) for 2 months after 3 months of regular diet. Various parameters of insulin resistance were measured. Morphology and functional activities of mitochondria were evaluated in tissues of ATZ-exposed animals and in isolated mitochondria. Chronic administration of ATZ decreased basal metabolic rate, and increased body weight, intra-abdominal fat and insulin resistance without changing food intake or physical activity level. A high-fat diet further exacerbated insulin resistance and obesity. Mitochondria in skeletal muscle and liver of ATZ-treated rats were swollen with disrupted cristae. ATZ blocked the activities of oxidative phosphorylation complexes I and III, resulting in decreased oxygen consumption. It also suppressed the insulin-mediated phosphorylation of Akt. These results suggest that long-term exposure to the herbicide ATZ might contribute to the development of insulin resistance and obesity, particularly where a high-fat diet is prevalent

Modélisation analytique des performances aéro-acoustiques des moteurs auto-ventilés de traction ferroviaire

The reduction of the noise generated by traction motors used in railway applications has become a very important criterion during their design phase. The overall noise comes from three main sources, of vibrational, aerodynamic and magnetic natures. Among these contributions, aero- dynamic noise is dominant at high rotation speeds. It is generated by the ventilation system of the motor. The use of numerical simulations to predict this noise can be very expensive and time-consuming when several geometrical parameters need to be tested. Analytical methods are suitable at the early design stage, due to their low computational time. This work is dealing with the analytical modelling of sound generation and propagation inside the ventilation systems integrated in electrical machines. In the first step of this work, the geometry of each motor is divided into several sub-domains, in which the sound field can be expressed as a sum of orthogonal modes. The analytical solution in each sub-domain requires the determination of the modal amplitudes of the different acoustic fields. The use of the mode-matching technique allows one to calculate these coefficients by imposing the continuity of the physical quantities at each interface between two sub-domains with different geometrical properties. A two-dimensional mode-matching technique is first applied to the sound generation and propagation in the fixed part of a totally-enclosed motor. The latter mainly consists of guide vanes and cooling channels. The equivalent dipoles are used in this work to model the sound generation by the impingement of the impeller wakes on the guide vanes. Then, the sound propagation in this coupled system is reproduced by the use of two transmission models which take into account the influence of the wall-thickness. An iterative method is used in order to take into account the multiple reflections of the acoustic waves between the guide vanes and the cooling channels. The mode-matching technique is then extended to significantly more complicated architectures in order to investigate how the sound can propagate inside the ventilation system of an open motor. The results obtained by the analytical models have been validated by comparison with the finite element method. A good agreement between the two methods was found. The diffraction of acoustic waves by periodic rows of rotating channels is addressed in last part of this work in order to investigate how sound can be transmitted through the rotating parts of traction motors. These analytical models are used for parametric studies to predict the acoustic resonances that can take place in the ventilation systems integrated in traction motors.La réduction du bruit des moteurs électriques de traction ferroviaire est devenue un critère très important lors de leur phase de conception. Le bruit global rayonné par ces moteurs est de natures vibratoire, magnétique et aérodynamique. Parmi ces contributions, le bruit aéro- dynamique est dominant aux vitesses élevées. Il est généré par le système de ventilation du moteur. L’utilisation des simulations numériques pour prédire ce bruit est très couteuse dans la phase de conception du moteur, où plusieurs paramètres géométriques doivent être testés. Les méthodes analytiques sont avantageuses lors de cette phase de conception en raison de leur faible coût de calcul. Ce travail a pour but de modéliser la génération et la propagation du bruit à l’intérieur des systèmes de refroidissement des moteurs électriques, en utilisant une approche analytique, basée sur la technique de raccordement modal. Dans la première étape de cette étude, la géométrie de chaque moteur est décomposée en plusieurs sous-domaines de géométrie simplifiée dans lesquels l’équation de Helmholtz est séparable. Cette étape de modélisation permet de trouver une solution analytique exprimée sous forme d’une somme de modes orthogonaux. La solution analytique dans chaque élément géométrique nécessite la détermination des coefficients modaux des différents champs acoustiques. L’utilisation de la méthode de raccordement modal permet de calculer ces derniers en écrivant la continuité des grandeurs physiques à chaque interface entre deux milieux de propriétés géométriques différentes. Cette méthode est d’abord appliquée dans un cadre bidimensionnel à la génération et à la propagation du bruit à l’intérieur de la partie fixe des moteurs fermés. Cette dernière est composée principalement d’une grille d’aubes et de canaux de refroidissement. L’utilisation de dipôles équivalents a permis de modéliser la génération de bruit par l’impact des sillages du ventilateur sur la grille d’aubes. La propagation du bruit dans ce système couplé est reproduite par l’utilisation de deux modèles de transmission qui prennent en compte l’influence de l’épaisseur des parois. Une méthode itérative est utilisée par la suite afin de prendre en compte les réflexions multiples des ondes acoustiques entre la grille d’aubes et les canaux de refroidissement. La technique de raccordement modal est ensuite étendue à des architectures beaucoup plus complexes pour étudier la propagation du son à l’intérieur du système de ventilation d’un moteur ouvert. Les résultats obtenus par les différents modèles analytiques sont comparés par la suite à des calculs par la méthode des éléments finis pour validation. La diffraction des ondes acoustiques par des réseaux de canaux tournants a été abordée dans la dernière partie de ce travail, afin de simuler la transmission du bruit à travers les parties tournantes des moteurs. Ces modèles analytiques sont utilisés pour des études paramétriques afin de prédire les résonances acoustiques qui peuvent se produire dans les systèmes de ventilation des moteurs

Intérêt de la planification tridimensionnelle dans les reconstructions mandibulaires

Le travail réalisé concerne l’apport des techniques de planification tridimensionnelle lors de reconstructions maxillaires ou mandibulaires. En effet, il est d’usage, chez les patients présentant d’importantes pertes de substance (traumatismes, cancers ou malformations congénitales) intéressant l’étage inférieur de la face, de procéder à des greffes reconstructrices : il est possible d’utiliser une pièce prothétique en titane, ou de prélever chez ce même patient un greffon osseux (auto-greffe) ultérieurement replacé à l’endroit de la perte de substance. Dans les deux cas, l’intégration biologique, esthétique et surtout fonctionnelle du greffon, à moyen et long termes, est essentielle. Celle-ci est toutefois régie par de nombreux facteurs, comme l’origine et la morphologie de la perte de substance, l’état biologique des tissus subsistants, la qualité du greffon (auto-greffe) ou la conception de l’endoprothèse. Nous aborderons les techniques numériques permettant d’appréhender spatialement la perte de substance, de prévoir l’architecture du greffon, et donc d’anticiper les éventuelles complications ou difficultés d’un tel traitement. Nous insisterons également sur la réhabilitation dentaire finale, simplifiée par des techniques de planification et de prévisualisation