Dry Matter Accumulation and Partitioning between Vegetative and Reproductive Organs in Alfalfa (\u3ci\u3eMedicago sativa\u3c/i\u3e L.)

This work investigated the partitioning of dry matter between vegetative and reproductive plant organs in alfalfa during the reproductive period under field conditions. Two French varieties (Europe and Magali) were studied. Both varieties showed similar growth pattern of the different plant organs in 1998 and 1999. The mean dry matter of vegetative organs (shoots and leaves) over the two years was higher in Europe (567g/m2) than Magali (470g/m2). No vegetative growth was observed during the reproductive period. The root organs (measured to a depth of 0.20 m) and the reproductive organs showed an increase in dry matter accumulation during the first 300 °Cd and 600 °Cd, respectively. It indicated that dry matter was preferentially partitioned to the reproductive organs during the first 600 °Cd. The root organs seem to be a competing sink during the early seed growth (200 °Cd to 300 °Cd). The dry matter partitioning was not affected by the year. Thus, when dry matter accumulation ceased only 30% in Europe and 27% in Magali of the aboveground dry weight was in the reproductive organs. The mean inflorescence weight reached its maximum after 450 °Cd from inflorescence flowering

Measurement and comparison of individual external doses of high-school students living in Japan, France, Poland and Belarus -- the "D-shuttle" project --

Twelve high schools in Japan (of which six are in Fukushima Prefecture), four in France, eight in Poland and two in Belarus cooperated in the measurement and comparison of individual external doses in 2014. In total 216 high-school students and teachers participated in the study. Each participant wore an electronic personal dosimeter "D-shuttle" for two weeks, and kept a journal of his/her whereabouts and activities. The distributions of annual external doses estimated for each region overlap with each other, demonstrating that the personal external individual doses in locations where residence is currently allowed in Fukushima Prefecture and in Belarus are well within the range of estimated annual doses due to the background radiation level of other regions/countries

Diallel analysis of pea aphid resistance in Alfalfa seedlings

International audienc

Genetic variability for morphology, growth and forage yield among perennial diploid and tetraploid lucerne populations (Medicago sativa L)

The wide diversity within the Medicago sativa complex is well known, but comparative data on different populations representing the sub-species sativa and falcata are lacking. Morphological and agronomic characters of 25 populations or varieties of lucerne belonging to the M sativa complex were studied at Lusignan (France) in 1993 and 1994. The landraces and varieties of the sub-species sativa were clearly different from the wild populations of the 2 sub-species sativa and falcata by their erect growth habit, their fast regrowth after cutting, the absence of rhizomatous plants, their tall height and their high forage yield. Within the cultivated populations, those originating from northern France had a higher winter resistance than the Mediterranean populations, and higher yields. The winter resistance trait and the variegated flowers of the French sativa landraces show that they have integrated some traits belonging to sub-species falcata. The group of wild populations contained diploid and tetraploid populations, and sativa or falcata populations. Among the characters analysed, only flower colour made the distinction possible between the wild sativa populations from Spain (Mielga) with purple flowers and the falcata populations with yellow flowers. This convergence of forms between the 2 sub-species could be a strategy of tolerance to animal feeding and to treading.Variabilité génétique pour la morphologie, la croissance et le rendement en matière sèche chez la luzerne pérenne diploïde et tétraploïde (Medicago sativa L). La grande diversité du complexe Medicago sativa est bien connue, mais des données comparatives de différentes populations représentant les sous-espèces sativa et falcata manquent. Les caractéristiques morphologiques et agronomiques de 25 populations ou variétés de luzerne appartenant au complexe M sativa ont été étudiées à Lusignan (France) en 1993 et 1994. Les populations et variétés cultivées de la sous-espèce sativa se distinguent nettement des populations sauvages des 2 sous-espèces sativa et falcata par leur port dressé, leur repousse rapide après une coupe, leur hauteur élevée et leur fort rendement. Parmi les populations cultivées, celles originaires du nord de la France ont une résistance à l'hiver supérieure aux méditerranéennes, ainsi qu'un meilleur rendement. Par leurs caractères de résistance à l'hiver et leurs fleurs bigarrées, ces populations sativa françaises montrent qu'elles ont intégré certains caractères provenant de la ssp falcata. Le groupe des populations sauvages comprend à la fois des populations diploïdes et tétraploïdes, falcata ou sativa. Pour les caractères analysés, seule la couleur des fleurs permet de distinguer les populations sauvages sativa d'Espagne (Mielga) à fleurs violettes des populations falcata à fleurs jaunes. La convergence de forme de ces 2 sous-espèces pourrait représenter une stratégie de tolérance au pâturage

Grain de resistance variétale de la luzerne au puceron du pois, estimé par deux critères lors de générations de sélection

National audienc

Prevalence of reading disabilities in early elementary school: Impact of socioeconomic environment on reading development in 3 different educational zones

International audienceObjective. Socioeconomic status (SES) has a known influence on academic achievement. Most studies, however, were conducted in English-speaking countries. Because recent cross-linguistic studies suggest that reading English is much harder to learn than reading other languages, an epidemiological study was conducted in French investigating the impact of socioeconomic background on early reading development. Design. One thousand and twenty second-grade children (476 girls and 544 boys) from 20 different schools participated in the study. Approximately 1/3 of the children lived and were schooled in a high SES area, 1/3 in an intermediate SES area, and one final third in a very low SES area. Assessment of reading, writing and mathematical skills was conducted initially in small groups. Children with suspected learning difficulties were further tested individually. Forty-two children of equivalent age who repeated the first grade received similar individual testing. Results. Average reading scores were in accordance with chronological age, without gender differences. Children from low SES schools had academic performances significantly lower than their peers. Boys exhibited superior arithmetic skills than girls. A significant reading delay was observed in 12.7% of children. The prevalence of poor reading was highly correlated with the area of schooling, varying from 3.3% in the high SES area to 24.2% in low SES area. Conclusion. The high rate of children from our sample with a significant delay in reading depended on general socioeconomic environment. An understanding of the origin of such differences is mandatory for defining and coordinating preventive actions and appropriate interventions. (C) 2008 Elsevier Masson SAS. All rights reserved