Introduction. The use of mycorrhizal fungi as biofertilizers can reduce chemical inputs during the nursery phase, allowing the production of high quality plant material with reduced fertilizer inputs. The lack of complete knowledge of each crop’s responsiveness to mycorrhizal symbiosis, however, is still a handicap to the routine application of this biotechnology for commercial purposes. In our work, the influence of early mycorrhization as an alternative to standard P fertilization programs for two tropical crops, papaya and pineapple, was assessed in a greenhouse experiment. Materials and methods. Papaya seedlings and pineapple planting material were inoculated with the arbuscular mycorrhizal fungus (AMF) Glomus mosseae and cultured on substrates with increasing amounts of soluble P. Data concerning plant development and nutritional status were determined 5 months (papaya) and 7 months (pineapple) after inoculation. Results. For both crops, benefits derived from mycorrhization, expressed in terms of plant development and nutritional status, were significantly higher than those derived from P application. Overall, mycorrhizal papaya plants exhibited significantly higher biomass and macroelement contents in shoots than plants without mycorrhizas at any P level. Mycorrhizal effects on pineapple at the lowest P level were significant in terms of plant development and P shoot contents. Conclusions. Differential benefits derived from mycorrhization seem to be correlated to each crop’s internal P requirements. Our work highlights the potential benefits of integrating early mycorrhization at the nursery stage in order to reduce P fertilizer inputs in sustainable plant production systems.

Introduction. While researchers have paid considerable attention to the effect of soil salinity on crop yield, methodological impediments remain when salinity is combined with other growth factors, especially in farmers’ fields. A specific methodology was adapted to assess the effect of waterlogging and salinity on date palm yield (Phoenix dactylifera L. cv. Deglet Noor). Materials and methods. Date palm yield, water table depth, irrigation water, groundwater and soil salinity were measured in 167 field plots located in five irrigation sectors of the Wargla basin (Algeria). Variance analysis and a boundary line approach were combined to analyze actual and potential yields according to environmental stresses. Results and discussion. High soil salinity resulted from saline irrigation water and a shallow water table. Actual yield decreased with the increase in soil salinity, the decrease in water table depth, and the presence of a gypsum-cemented horizon within the soil profile. The significant effect of the interaction between water table depth and soil salinity showed that the crop responded to the most severe stress rather than to combinations of the individual effects. Potential yield was assessed according to classes of water table depth, soil salinity and the occurrence of a gypsum-cemented horizon. The relationship between soil salinity and potential yield was calibrated according to two models. The limiting factors in order of decreasing importance were shallow water table, high soil salinity and occurrence of a gypsum-cemented horizon for 38.3%, 16.8% and 2.4% of the field plots, respectively; there was no limiting factor for 42.5% of the field plots. In certain sectors, actual yields remained far below potential yields and the additional effect of irrigation water salinity could thus be considered.

Introduction. Depuis quelques années, le séchage des fruits et légumes à petite échelle connait un regain d’intérêt au Cameroun, que ce soit pour la vente locale ou pour celle d’exportation. Or, les transformateurs qui pratiquent cette activité ne sont pas satisfaits des séchoirs qu’ils utilisent. Matériel et méthodes. Dans ce contexte, nous avons réalisé une enquête de type semi ouvert auprès d’une cinquantaine d’unités de séchage installées dans les zones de Douala et de Yaoundé (Cameroun) afin de mieux identifier les difficultés qu’elles rencontrent. Les informations obtenues au cours de cette enquête ont été codifiées pour faciliter leur exploitation informatique. Nous n’avons conservé dans l’échantillon constitué que les entreprises travaillant à petite échelle (70 % de l’échantillon initial), c’est-à-dire traitant moins de 500 kg de produits frais par cycle de séchage. Résultats. L’analyse des résultats a montré que près de 45 % des unités étudiées ne possédaient pas de séchoir et que 70 % des séchoirs recensés dans les unités qui en étaient équipées étaient des séchoirs à gaz. Dans l’ensemble, près de 92 % de ces séchoirs sont des séchoirs à convection naturelle. Le modèle de séchoir connu est le modèle Atesta importé du Burkina Faso dont des variantes sont fabriquées localement. Il s’avère que ce modèle ne répond que partiellement aux besoins des utilisateurs et que les transformateurs locaux abandonnent de plus en plus ces séchoirs. Conclusion. L’état de lieux des activités de séchage à petite échelle des fruits et légumes dans le sud du Cameroun a fait apparaître que, malgré les différentes offres disponibles localement, le besoin en dispositifs de séchage répondant mieux aux attentes des utilisateurs reste très important. Ce besoin se traduit par une volonté d’acquérir des séchoirs présentant la capacité de traiter plus de 80 kg de produits frais durant un cycle de séchage de 10 h, et équipés d’un système de ventilation et de régulation des paramètres de séchage.

Introduction. Physalis minima is a widespread, quick-growing and high fruit-yielding annual herb belonging to the family Solanaceae. However, like many other underutilized fruit-bearing plants, P. minima is poorly studied and its nutritional potential is unknown. Since the edible sunberry is said to be a rich source of vitamin C, we studied the physiochemical changes during its fruit growth and ripening. Materials and methods. The changes in the physiochemical properties, such as pH, total soluble solids, titrable acidity, chlorophylls, carotenoids, carbohydrates (reducing sugars, non-reducing sugars, total sugars and starch), free amino acids, total proteins, total phenols, ascorbic acid, ethylene, and respiration and the activities of hydrolytic enzymes (amylase and invertase), antioxidant enzymes (catalase and peroxidase), and cell wall-degrading enzymes (cellulase, polygalacturonase and pectinmethylesterase), were analyzed in the fruit of sunberry at five sequential stages, viz., the young, premature, mature, preripe and ripe stages. Results and discussion. A gradual increase in the pH and total soluble solids occurred throughout the growth and ripening of sunberry fruit, while its titrable acidity increased up to the preripe stage and thereafter declined. A decreasing trend in the chlorophylls occurred simultaneously with an increase in the quantity of carotenoids. As the sunberry fruit proceeded towards ripening, the amount of its total starch decreased, with a concomitant sharp increase in the quantity of its reducing sugars, non-reducing sugars and total sugars. An increase in the quantity of free amino acids, proteins and phenols also occurred during the growth and ripening of the fruit, and the quantity of ascorbic acid increased at the mature stage. Moreover, sunberry fruit also exhibits a climacteric behavior with increased ethylene production and rate of respiration. The specific activity of amylase increased throughout the growth period of sunberry, but that of invertase decreased after maturity until ripening. The catalase and peroxidase enzymes showed higher activity, indicating better radical scavenger properties, while cellulase, polygalacturonase and pectinmethylesterase tended to remain at lower levels. Conclusion. The fruit of P. minima are nutritive and a rich source of sugars, starch, free amino acids, proteins, total phenols and ascorbic acid. They are metabolically active, showing a high specific activity of hydrolyzing and antioxidant enzymes, while the activity of cell wall-degrading enzymes is relatively low, indicating a better postharvest storage life.

Introduction. Dabai (Canarium odontophyllum Miq.) fruit is an underutilized fruit found in Borneo, Palawan and Sumatra. To our knowledge, no literature exists about the postharvest quality characteristics of dabai fruit. Furthermore, it is a unique fruit whereby the fruit is served by steeping at about 60 °C for 15–20 min to soften the flesh. Therefore, a preliminary study was conducted to determine the physicochemical characteristics of dabai fruit before and after steeping. Materials and methods. Physicochemical characteristics (skin color, size, shape, weight, mesocarp thickness, firmness, soluble solids concentration, pH, titratable acidity, organic acids, respiration production rate and ethylene concentration) of dabai fruit were determined before and after steeping in hot water at 60 °C for 15 min. Results. The color of mature dabai fruit is dark purplish with very low chromaticity. The fruit is oval-shaped with a length to diameter ratio of 1.40. The seed contributes 61% of the fruit weight. After treating fresh dabai fruit with 10 mL·L-1 ethylene at 20 °C, the respiration production rate decreased while ethylene concentration increased. After steeping dabai fruit at 60 °C for 15 min, the flesh firmness decreased while soluble solids concentration increased tremendously. After steeping, the pH of fruit decreased and titratable acidity increased, as did the citric, malic and succinic acids of dabai fruit, especially citric acid. Conclusion. Steeping softens dabai fruit flesh and makes it palatable, with high soluble solids concentration and organic acids. The high respiration production rate means that dabai fruit has a short shelf life under non-cold chain handling practices.

Introduction. Turkey potentially has a very rich source of sweet (Prunus avium) and sour (P. cerasus) cherries. P. avium is apparently native to some parts of Northern Turkey, where Giresun is located. Identification of the sweet cherry cultivars produced in Turkey will help in choosing appropriate cultivars and aid in the preservation of natural resources required for breeding studies. The most conventional method of cultivar identification is based on the assessment of morphological characteristics. However, this method is insufficient to distinguish closely related cultivars. The aims of our study were to determine the molecular profile of sweet cherry accessions grown in Giresun, Turkey, and to determine their genetic relationships. Materials and methods. In our study, we identified 44 sweet cherry accessions grown in Giresun by using genetic markers (SSR, Simple Sequence Repeat), and we determined the genetic relationships among the sweet cherry genotypes. For DNA isolation, we collected young leaves sampled on a single plant per accession, then amplification of microsatellite loci was performed. In total, ten SSR primer pairs, previously isolated from peach and sweet cherry, were used. Genetic similarity values were calculated. A cluster analysis was performed to generate a dendrogram. Results and discussion. Of the ten primers tested, six primer pairs did not result in suitable amplification products with the 44 accessions studied. The remaining four polymorphic SSR primer pairs produced 33 alleles with an average of 8.25 putative alleles per locus, ranging from 7 to 11. Depending on the accessions, similarity ratios ranged from 0.32 to 0.98, with a mean value of 0.64. In conclusion, the results obtained demonstrate a high level of polymorphism among sweet cherry genotypes from a single province in Turkey.