Frequences stomatiques de l'aubergine (Solanum melongena L.) et relations avec le developpement racinaire

National audienceMediterranean eggplant varieties (M) had higher stomatal index and stomatal density than far-eastern varieties (EO in text) both for young plants with 5-6 leaves grown in a greenhouse and for adult plants grown in the open under summer irrigation. This result was the same when the natural light level was 50 % reduced by shade. Stomatal frequency means of varieties were po.sitively related (see fig. 5) with their root dry weight means. The significance of this result lies in the suggestion that stomatal parameter measurements may provide a "non destructive" method of determining root dry matter. Further work will examine this question more closely.Les variétés d’aubergine méditerranéennes ont un indice et une densité stomatiques supérieurs à ceux des variétés extrême-orientales, aussi bien dans le cas de jeunes plantes de 5-6 feuilles élevées en serre, que dans celui des plantes adultes cultivées l’été au champ. Ce résultat ne varie pas quand le niveau d’éclairement naturel est diminué de 50 p. 100 par ombrage. Les fréquences stomatiques moyennes des variétés sont en relation positive avec les poids secs moyens de leur système racinaire. Ce résultat suggère que les mesures de fréquence stomatique pourraient devenir une méthode « non destructive » de mesure de la matière sèche des racines. Un travail futur examinera cette question plus précisément

Influences reciproques des racines et des parties aeriennes sur le rendement de l'aubergine (Solanum melongena L.): resultats de greffages inter-varietaux

National audienceMeasurements have been made of the effects of root growth and shoot development on irrigated eggplant fruit production. Roots and shoots of a Mediterranean variety and an other from the Far East were exchanged by grafting. Growth and fruit production of these inter-ecotype plants (tables 1 & 2) showed that roots and shoots had an equal and reciprocal influence on fruit number, whereas the root growth effect was mainly on mean fruit weight. Therefore with better root and shoot growth, the Mediterranean variety has the largest fruit production under irrigation in the south of France.Afin de mesurer les effets de la croissance racinaire et des parties aériennes sur la production de l’aubergine de plein champ irriguée, les racines et les parties aériennes d’une variété méditerranéenne ont été échangées par greffage avec celles d’une variété venant d’Extrême-Orient. Les performances des plantes inter-écotypiques montrent que les racines et le feuillage ont des influences réciproques et équivalentes sur le nombre de fruits ; par contre, le développement racinaire a une influence prédominante sur le poids moyen des fruits. Aussi avec une croissance aérienne et racinaire supérieure, la variété méditerranéenne a le meilleur rendement en culture irriguée de plein champ dans le Sud de la France

Facteurs agro climatiques influencant la resistance stomatique de l'aubergine (Solanum melongena L.)

National audienceLeaves of three eggplant varieties from the Far East and three from the Mediterranean always had low abaxial stomatal resistance, even under 50-100 W .m-2 light (fig. 1). Therefore, the major part of plant transpiration passed through the abaxial surface of leaves. An inter-ecotype grafting experiment showed that roots have a slight influence on leaf stomatal resistance if the soil is kept wet (fig. 4). In a climate chamber, eggplant varieties from the Far East (EO in text) had significantly lower stomatal resistances than those of Mediterranean varieties (M) at air temperatures less than 25 °C, i.e. under temperature conditions common in greenhouses. At higher temperatures closer to those prevailing in the field under summer irrigation, these differences between the two ecotypes decreased until by 35 °C they had completely disappeared (fig. 3). This result has been confirmed by measurements in the field. Finally irrigated Mediterranean varieties in the open transpire more than their Far eastern counterparts by virtue of their greater leaf area per plant. This is possible because of their larger root systems which give access to a greater volume of stored soil moisture. This better exploitation of water resources is the key to their higher yield capacity under irrigation in a Mediterranean climate.Chez l’aubergine, du moins chez 3 variétés extrême-orientales et 3 méditerranéennes, la résistance stomatique de la face inférieure des feuilles reste toujours faible même sous un éclairement de 50 à 100 W .m-2 l’essentiel de la transpiration se fait probablement par la face inférieure des feuilles. Une expérience de greffage inter-écotypique montre que les racines ont une légère influence sur la résistance stomatique des feuilles quand le sol est maintenu très humide. En chambre climatisée, les résistances stomatiques des variétés d’aubergine extrême-orientales sont significativement inférieures à celles des variétés méditerranéennes lorsque les températures de l’air sont inférieures ou égales à 25 °C, c’est-à-dire dans les conditions thermiques qui prévalent pour des cultures sous serres. Par contre, aux températures supérieures - plus proches de celles qu’on trouve en culture estivale de plein champ - la différence de résistance stomatique entre les 2 écotypes s’atténue pour devenir nulle à 35 °C. Des mesures sur des cultures de plein champ ont confirmé ce résultat. Finalement, en culture irriguée de plein champ, les variétés méditerranéennes transpirent plus que les extrêmeorientales à cause de leur surface foliaire totale plus grande. Le surplus d’eau nécessaire est fourni grâce à leur système racinaire beaucoup plus développé. Cette meilleure exploitation des ressources en eau est la clef de leur rendement supérieur en culture irriguée de plein champ sous climat méditerranéen

The control of soil borne vascular diseases: Limits of genetic resistance of cultivars and rootstocks for controlling <em>Fusarium</em> <em>oxysporum</em> f. sp. <em>melonis</em> (melon) and <em>Verticillium</em> sp. (eggplant)

International audienceAfter using resistant cultivars or resistant rootstocks for many years to control soil-borne pathogenic fungi causing wilt disease, growers observe more and more frequently wilt like symptoms in their melon and eggplant cultures. Ctifl, in close collaboration with INRA, regional extension services, and seed companies, set up a study designed to investigate the causative pathological agents. The results show the prevalence of Fusarium oxysporum f. sp. melonis race 1-2 yellowing on melon and of Verticillium dahlia on eggplant. Both pathogens are often found together with other pathogenic soil fungi, which act as aggravating factors. The isolates of F. oxysporum f. sp. melonis collected from infected plants appear to be more aggressive than the reference strains currently used for screening resistant material in breeding programmes. In the case of Verticillium wilt, the taxonomic and race status of the isolates sampled, remain unclea

Bacterial wilt resistance in tomato, pepper, and eggplant: genetic resources respond to diverse strains in the Ralstonia solanacearum species complex

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699International audienceBacterial wilt, caused by strains belonging to the Ralstonia solanacearum species complex, inflicts severe economic losses in many crops worldwide. Host resistance remains the most effective control strategy against this disease. However, wilt resistance is often overcome due to the considerable variation among pathogen strains. To help breeders circumvent this problem, we assembled a worldwide collection of 30 accessions of tomato, eggplant and pepper (Core-TEP), most of which are commonly used as sources of resistance to R. solanacearum or for mapping quantitative trait loci. The Core-TEP lines were challenged with a core collection of 12 pathogen strains (Core-Rs2) representing the phylogenetic diversity of R. solanacearum. We observed six interaction phenotypes, from highly susceptible to highly resistant. Intermediate phenotypes resulted from the plants’ ability to tolerate latent infections (i.e., bacterial colonization of vascular elements with limited or no wilting). The Core-Rs2 strains partitioned into three pathotypes on pepper accessions, five on tomato, and six on eggplant. A “pathoprofile” concept was developed to characterize the strain clusters, which displayed six virulence patterns on the whole set of Core-TEP host accessions. Neither pathotypes nor pathoprofiles were phylotype specific. Pathoprofiles with high aggressiveness were mainly found in strains from phylotypes I, IIB, and III. One pathoprofile included a strain that overcame almost all resistance sources

More efficient conservation and use vegetable genetic resources in Europe: ECPGR achievements

International audienc

More efficient conservation and use of vegetable genetic resources in Europe: ECPGR achievements and perspectives

The European Cooperative Programme for Plant Genetic Resources (ECPGR) is a regional network funded by the European countries and coordinated by Bioversity International. The Vegetables Network with representatives of 42 countries, is one of the crop specific ECPGR networks (http://www.ecpgr.cgiar.org/ networks/vegetables.html). It consists of six Working Groups (WGs), i.e., on Allium, Brassica, Cucurbits, Leafy Vegetables, Solanaceae and Umbellifer Crops. Sharing responsibilities for the ex situ conservation of European vegetable crops genetic resources is the highest priority of the Vegetables Network. It is foreseen that the rationalization of the collections will lead to higher cost-efficiency, and improvement of plant genetic resources documentation and quality. These efforts will be continued within the framework of the AEGIS initiative (A European Genebank Integrated System) (http://www.aegis.cgiar.org/). Challenges for the Vegetables Network include the identification of the so-called Most Appropriate Accessions (MAA) for each crop for their inclusion in the decentrally managed European Collection, and the development of agreed crop specific technical standards for conservation. Achievements of the Network in recent years include the development of European Central Crop Databases (ECCDBs), quality standards for collection man-agement of seed-propagated crops and cryopreserved material, safety duplication improvement and definition of minimum characterization descriptors. Several EU-funded projects have initiated and accelerated the activities of the WGs. Apart from further improvements within the framework of AEGIS, the Network is planning a number of other initiatives, such as improving collaboration at the global level (Allium), developing molecular characterization protocols (lettuce), filling the gaps in the conservation of wild relatives (Brassica and Umbellifer Crops), and improving the Network’s communication with the scientific community and the public at large

La conservation et la connaissance des ressources génétiques d'espèces végétales cultivées: un enjeu pour l'agriculture et un défi pour les acteurs

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