Introduction. In the French West Indies, farmers generally consider thatperiodical soil tillage is necessary to increase soil porosity and maintain high yield.However, in the non-tilled perennial banana plantations of the highlands, the soilexhibits better physical and biological properties than in the conventional bananaplantations. To determine if tillage before banana planting is necessary for proper bananacrop functioning and to assess the effect of tillage on soil quality, banana plantingafter conventional tillage was compared with no-till banana planting on crop residue mulchon an experimental plot. Materials and methods. Soil quality was assessedthrough indicators such as porosity, organic status, microbial biomass and structure ofnematode communities. Crop functioning was assessed through plant growth, rootdistribution, and soil water and nitrogen availability. Results. We foundthat tillage reduced soil microbial biomass and the number of nematode functional guilds.Tillage had only a short-term effect on soil porosity and did not allow deeper extensionof the root system. Although soil organic nitrogen mineralization was higher withconventional tillage, banana nitrogen nutrition was not better, probably because the highnitrogen fertilization offset the variations in availability of nitrogen from organicorigin. We found that banana growth was better with no-till treatment. This could beexplained by less drying out of soil due to the crop residue mulch left on the soilsurface with no-till treatment. Conclusion. Relative to conventional tillage,no-till banana planting improved soil quality and crop performance.

Introduction. The peel of bananas that ripen at ≥ 24 ℃ does not turn fullyyellow, but retains a green colour, reducing the commercial value of the fruit.Historically, in experimental studies of this problem, fruit are ripened at constanttemperatures; for example, either 20 ℃ or 30 ℃. In our experiments, we systematicallyvaried the temperature of banana storage during ripening to investigate early events inripening that may determine whether or not the peel remained green. Materials andmethods. Fruits were exposed to temperatures of 20 ℃ or 30 ℃ for short periodsbefore then storing at 30 ℃ or 20 ℃ to complete ripening. The L* a* b*colour system was used to measure change in green colour in the banana peel.Results. If the temperature of the fruit stored was 20 ℃ for the first fewhours (≥ 14 h), then the peel became fully yellow, even in fruit subsequently ripened at30 ℃. Conversely, if the temperature of the bananas stored was 30 ℃ for the first fewhours of ripening, then full yellow colour was not obtained even if fruits weresubsequently ripened at 20 ℃. Conclusion. The temperature of the first few hours of bananaripening determines whether or not the peel reaches full yellow colour.

Introduction. Celtis australis L., Crataegusazarolus L., Crataegus monogyna Jacq., Elaeagnusangustifolia L. et Zizyphus lotus L. sont des arbres etarbustes fruitiers non conventionnels, très communs en Afrique et surtout en Algérie.Leurs fruits traditionnellement exploités sont sources de minéraux et vitamines quipourraient constituer une matière première non négligeable pour l’alimentation. Ils sontconsommés frais ou secs. L'objectif de notre travail a été de déterminer la compositionminérale et vitaminique de ces fruits. Matériel et méthodes. Notre étude aporté sur une comparaison de ces fruits quant à leurs caractéristiques biométriques et àla teneur de leur portion comestible en composés vitaminiques et éléments minéraux.Résultats et discussion. La pulpe des cinq fruits étudiés s’est révéléeplus riche en vitamines (tocophérol, carotène, vitamine C, thiamine B1) et enminéraux (calcium, magnésium, potassium, fer, manganèse ) que certains fruits pluslargement consommés. La teneur de quelques oligo-éléments (zinc, cuivre) n’a pas dépasséle seuil de toxicité, indiquant que la consommation de ces fruits n’était paspréjudiciable à la santé publique. Conclusion. Les fruits analysés pourraientêtre source d’un apport nutritionnel important et être utilisés dans différents domaines :agroalimentaire, cosmétique, pharmaceutique et autres.

Introduction. The traditional curing of vanilla pods includes “killing” andsweating steps when pods are exposed to heat (35–65 ℃) for various lengths of time.Although it is known that liberation of vanillin and other phenolics from theirnon-aromatic glucosides is due to the action of an endogenous β-glucosidase, itsin vivo kinetics remained unknown. Materials and methods.Mature green vanilla pods were pretreated for 2 h at 50 ℃, 55 ℃ and 60 ℃, then stored for118 days at 27 ℃. Phenolic glucosides and their aglycons were extracted at regularintervals during the storage period and analyzed by HPLC. Results anddiscussion. All phenolic β-glucosides were slowly hydrolyzed during the storageperiod with production of vanillin, p-hydroxybenzaldehyde, vanillic acid,and other unknown aglycons. Most of the β-glucosidase was heat-denatured by thepretreatment, and analysis of its kinetic parameters showed that it adopts, invivo, an allosteric mode of functioning with a lower affinity for glucovanillinthan in vitro, where it behaves as a Michaelian enzyme.Conclusion. Extensive research is needed to confirm the allostericmechanism of the vanilla β-glucosidase in vivo.

Introduction. Drought stress is the major factor affecting growth,development and production of walnut trees. In Iran, approximately 33 Mha of land isaffected by salinization and drought stress. Finding genetic resources tolerant to droughtstress at different growth stages is important for such semi-arid regions. Our aim was tounderstand better the adaptive mechanisms that enable different genotypes of walnutpopulation to survive under drought stress, and to provide some useful clues for walnuttree breeding toward improved drought tolerance with utilization of existingdrought-tolerant genetic resources. Materials and methods. To study themechanism(s) involved in drought tolerance of some Persian walnut genotypes, droughtstress was induced using polyethylene glycol-6000 to produce water potentials of 0 Mpa(control), –0.10 MPa, –0.50 MPa, –0.75 MPa, –1.00 MPa, –1.50 MPa and –2.00 MPa. The amountof proline and soluble sugar accumulation in four walnut genotypes(‘Panegine20’, ‘Lara’, ‘Serr’ and ‘Chandler’) were determined after beingexposed to the various water potential levels. Results. The rates of seedgermination in all genotypes were significantly reduced by low external water potentials.Plants exposed to water stress had a higher amount of soluble sugars in roots and shootsof tolerant genotypes (‘Panegine20’ and ‘Chandler’) and a lower amount ofstarch in their tissues. These results imply the important roles of soluble sugars assolutes conferring resistance to drought in these genotypes. The free proline levels werealso increased in response to drought stress. They were higher in drought-tolerantgenotypes than in sensitive ones (‘Lara’ and ‘Serr’). Proline increased more in shootsthan in roots. However, the soluble sugar and starch fluctuations were higher in theroots. Conclusion. Our results support a direct correlation between thedegree of drought stress and proline content. As a consequence, proline concentrationscould be used as a biochemical marker of drought stress level in walnut plants.

Significance of fruit flies in vegetable crops. Vegetable crops hold a keyposition in agricultural production in Reunion (Indian Ocean); however, many pests anddiseases threaten the profitability of this agricultural sector. Fruit flies (Diptera:Tephritidae) figure among the main pests for solanaceous crops and cucurbits (cucumber,zucchini, melon, etc.). Losses of as much as 80% of tomato and 100% of cucurbit cropharvests have been frequently observed. Inventory and distribution. Fourfruit fly species belonging to the Tephritidae family cause major damage to vegetablecrops in Reunion: Bactrocera cucurbitae (Coquillet), Dacusciliatus Loew and D. demmerezi (Bezzi) on Cucurbitaceae, andNeoceratitis cyanescens (Bezzi) on Solanaceae (primarily the tomato).Distribution of each of them is presented. Biology and behavior. A fewstudies on the biology and behavior of the four fruit flies were conducted in Reunion inthe late 1990s. Their main biological characteristics are summarized. Populationcontrol methods used in Reunion. Various methods such as chemical control,preventive measures (sanitation), physical control, biotechnical control [colored traps,the Male Annihilation Technique (MAT) and the Bait Application Technique (BAT)], andbiological control currently used in Reunion against fruit flies are reported. Othercontrol methods such as Integrated Pest Management and the Sterile Insect Technique arenot used in Reunion. Prospects for implementing agro-ecological management ofvegetable fruit flies in Reunion. This part presents research actions implementedin fly bio-ecology, research actions into the genetic structure of populations and designof an agro-ecological management scheme for vegetable fruit flies.Conclusions. The control methods used independently have not beensuccessful to effectively control tephritid populations. A more integrated approach isrequired, also taking into account the landscape scale and its mosaic of habitats,especially wild plants, whose role must be considered within a framework ofagro-ecological management of these pest populations.