Introduction. A study of accessions from the major production areas of Dacryodes edulis (Don) Lam. (Burseraceae) in Cameroon was carried out in order to assess the impact of pedoclimatic parameters and genetic factors on the characteristics and the classification of the fruits. The work focused on statistical analysis of fruit morphological and chemical parameters to distinguish accessions. Materials and methods. The fruits were collected from five localities of Cameroon (Obala, Boumyebel, Makenene, Njombe and Kekem). Twenty-six characters, among which were eleven quantitative morphological, nine qualitative morphological and six chemical characters, were the object of a correlation analysis, a principal component analysis and hierarchical classification. Results. Among the twenty-six characters studied, eighteen presented interesting morpho-chemical characters to discriminate the accessions. The fruit quantitative morphological characters were not significantly different, while the qualitative morphological and chemical characters showed significant differences for the localities concerned. A principal component analysis and hierarchical classification distinguished three major groups at a genetic distance of between 5.70 and 6.92: group I consists of accessions from Makenene and Kekem, discriminated by five characters (lipids, protein, grain colour, texture and colour of the mesocarp); group II consists of accessions from Njombe and Obala and was discriminated by six characters (weight of fruits, amino acids, sugars, phenols, epicarp colour and shape of grains); group III consists of the accession from Boumyebel and was discriminated by seven characters (fruit length and diameter; [fruit diameter / fruit length] ratio; weight of fruit, mesocarp and grain; and mesocarp thickness). Discussion and conclusion. Like agro-forestry species such as Ricinodendron heudelotii and Irvingia gabonensis, D. edulis presents intra-specific variations that are related to pedoclimatic conditions and genetic factors.

Introduction. En Tunisie, les dattes de type Deglet Nour sont réputées pour leur couleur jaune doré et elles présentent une valeur marchande élevée ; elles constituent la majorité des dattes exportées vers l’Europe. L’objectif de nos travaux a été d’étudier l’effet de l’oxygène et de la température sur la dégradation de la couleur de ce type de dattes durant la période d’entreposage. Matériel et méthodes. L’évolution de la couleur de dattes du type Deglet Nour stockées sous humidité relative constante (75 %), à trois températures différentes [(10, 25 et 37) °C] et en présence de trois concentrations d’oxygène [(0, 20 et 40) %] a été suivie chaque semaine durant 35 jours à l’aide de la mesure des paramètres L* et b* de l’échelle Hunter Lab. Résultats. La température a joué un rôle déterminant dans la dégradation de la couleur des dattes durant l’entreposage et l’effet de l’oxygène a été important quoique secondaire. Conclusion. La couleur des dattes au cours de leur stockage se révèle pouvoir être prédite à partir du seul paramètre b* de l’échelle Hunter Lab. Dans le cas des dattes conditionnées sous différentes concentrations en oxygène et à différentes températures, la perte de la couleur initiale du fruit a été davantage expliquée par une augmentation de la température ambiante que par la variation de la concentration en oxygène du milieu de conservation. La dégradation de la couleur serait causée par des brunissements non enzymatiques et enzymatiques oxydatifs.

Introduction. Tamarind (Tamarindus indica L.) belongs to the Fabaceae family; it is a multipurpose tree with slow growth. In order to help improve its growth and development, we assessed mycorrhizal diversity of tamarind parklands in Senegal. Materials and methods. Three sites of tamarind populations were sampled for each agro-ecological zone in Senegal: the Sahelian zone (i), Sahelo-Sudan zone (ii) and Sudan zone (iii). Soil and root samples were collected in each site and used for arbuscular mycorrhizal (AM) spore isolation and root colonization assessment. We identified the mycorrhizal fungi from spore collections and evaluated the root mycorrhization rate, defined as percentage of roots colonized according to agro-ecological zones. Results and discussion. The results did not reveal a specific AM fungal strain associated with tamarind plants. Three arbuscular mycorrhizal fungi (AMF) were identified from spores on the genus level: Glomus, Scutellospora and Acaulospora. Tamarind sites with sandy soil texture (70–90%) and located in dry areas (Sahel and Sudano-Sahel zones) were shown to be rich in mycorrhizal propagules. High densities of soil AM propagules evaluated with the Most Probable Number method (MPN) were found in Niokhoul (1100 propagules per 50 g of soil), Sakal (790 propagules per 50 g of soil) and Mbassis (780 propagules per 50 g of soil). However, higher mycorrhizal colonization (11%) was observed in the Sahel agro-ecological zone compared with the Sudano-Sahelian and Sahelian zones (3%) of Senegal. Conclusion. Our study explored natural AMF diversity as a starting point to develop inocula to be used in commercial nursery production of tamarinds.

Introduction.Detarium microcarpum Guill. et Perr., espèce forestière fruitière de la zone soudano-sahélienne, est actuellement menacée de disparition au sud du Mali suite à des actions anthropiques. L'objectif global des travaux présentés a été d'inventorier les connaissances des populations locales sur la plante afin d'acquérir des informations relatives à la caractérisation, la gestion, la protection et l'utilisation durable des ressources génétiques de D. microcarpum dans cette zone. Matériel et méthodes. Une enquête a été menée, par interviews, sur la base de questionnaires ouverts dans 23 villages (216 personnes) appartenant aux zones agro-écologiques du plateau de Koutiala au sud du Mali. Résultats et discussion. L'enquête a confirmé que l'espèce joue un rôle important sur les plans socioculturel, médicinal, écologique et environnemental au sud du Mali. Les critères d'appréciation paysans des écotypes de D. microcarpum portent surtout sur la couleur de l'écorce, la taille des feuilles et la qualité des fruits. Selon les personnes interrogées, la perpétuation de D. microcarpum passe par la réglementation de la coupe de bois et le contrôle des feux. Conclusion. Les connaissances locales permettront d'élaborer une stratégie de conservation durable de D. microcarpum. Auparavant, certains aspects devront être élucidés.

Introduction. La durée de vie verte (DVV), qui indique l’état physiologique des bananes à la récolte, est un critère de qualité majeur pour l’exportation des fruits. Afin d’évaluer et de comprendre la variabilité de la DVV existant en exploitation, une enquête diagnostic a été menée chez trois producteurs de bananes en Martinique utilisant la méthode des sommes thermiques comme outil de décision de récolte. Matériel et méthodes. Pour chaque producteur, des fruits ont été prélevés en sortie de station d’emballage sur 10 % des régimes récoltés pendant une semaine. Ces bananes ont ensuite été conservées à 14 °C dans des sacs perforés en polyéthylène jusqu’au stade de maturité « tournant vert ». La DVV a été définie par le temps écoulé en jour entre la récolte et ce stade de maturité. Résultats et discussion. La DVV a varié entre (18 et 69) jours avec une moyenne de 42 jours pour l’ensemble des producteurs. Près de 80 % de la production a eu une DVV entre (25 et 50) jours et moins de 4 % en dessous de 25 jours. La variabilité de la DVV a été liée principalement à l’âge des fruits à la récolte, exprimée en somme thermique (R = –0,74). Celle-ci a varié entre (600 et 1150) degrés-jour pour l’ensemble des exploitations. Les fruits contaminés par l’anthracnose de blessure et les pourritures de couronne ont présenté une DVV plus courte que les fruits sains et cela indépendamment du stade de récolte (p < 0,001). L’origine de cette contamination a été discutée. À même somme thermique, des différences significatives de DVV ont été mises en évidence selon le lieu de production (parcelle) (p < 0,001). Des écarts de plus de 7 jours en moyenne ont été observés entre des parcelles provenant du même producteur et situées à même altitude. L’origine de ces différences a également été discutée.

Introduction. The fruit of Averrhoa carambola L., or carambola, is an attractive tropical fruit of the Oxalidaceae family. As most of the carambola crop is consumed fresh, very few carambolas are processed. However, the high variability in fruit quality produced by Caribbean countries is a major limitation to market penetration. Processing of carambolas could allow the utilization of low quality fruits, which cannot be marketed, to reduce waste, improve on the economic returns of farmers and increase the value of the crop. Our work thus aimed at studying carambola wine quality in relation to certain treatments applied before the fermentation of the must. Materials and methods. Pectolase was added to the pasteurized carambola pulp to the concentrations of (0, 0.1, 0.2 and 0.3)%. Another treatment used pectolase to 0.3% with addition of 1% of citric acid and 0.25% of ascorbic acid and associated with the use of various yeast strains of Saccharomyces cerevisiae from various wines (Super, Chablis and Sweet Mead). The must was adjusted to 25 °Brix and pH 3.0–3.5. The carambola wine quality obtained at the end of each treatment was assessed using physicochemical characteristics and sensory evaluations. Results and discussion. Addition of pectolase improved the carambola wine’s light transmittance, sensory color, sensory clarity and overall acceptability. Addition of 1% citric acid and 0.25% ascorbic acid to the must resulted in less dark and yellow wines with a more acceptable color. Wines fermented with the Chablis yeast strain had the highest clarity (88.55% of light transmittance). The wines were microbiologically stable. Conclusion. Carambola wine treated with 0.3% pectolase with the inclusion of 1% citric acid and 0.25% ascorbic acid with different yeast strains had (7.35 to 7.65) °Brix, (10.25 to 11.50)% alcohol, pH 3.01 to 3.02, (79.20 to 88.55)% of light transmittance and (17.50 to 17.76) mg ascorbic acid·100 mL–1. These wines had overall acceptability rating from slightly to moderately liked and they were judged as superior.

Introduction. The raphia palm tree is found in abundance in the southern part of Nigeria, especially in the southeastern part. It is grown mainly for its production of palm wine. It also bears fruits (Raphia hookeri) whose pulp is considered edible in some parts of the country and not edible in other parts. Materials and methods. Conventional methods of analysis were used to investigate the vitamin, phytochemical and toxic element composition of the pulp and seed of the fruit. Results. The investigation shows that the pulp has higher concentrations of vitamin E (1.04 mg·100 g–1), niacin (0.2 mg·100 g–1), alkaloid (5 g·kg–1), saponins (3.6 g·kg–1), flavonoids (4 g·kg–1) and phenols (4.1 g·kg–1) than the seed, but the seed has higher values of vitamin A (0.16 mg·100g–1), thiamine (0.07 mg·100 g–1), riboflavin (0.07 mg·100 g–1), nitrates (3.05 mg·100 g–1) and nitrites (0.29 mg·100 g–1), and of the toxic elements: lead (0.03 µg·g–1), mercury (0.04 µg·g–1), arsenic (0.23 µg·g–1) and cadmium (0.04 µg·g–1) than the pulp. Conclusion. The pulp and seed of R. hookeri are non-toxic and can serve as food as well as in medicine.

Introduction. Aroma is often used as a fruit quality marker. Several researchers have used the analysis of volatile compounds to characterize dates (Phoenix dactylifera). Nevertheless, it is difficult to analyze this subtle aroma in spite of the many techniques available, such as liquid-liquid extractions and headspace analysis. The global approach of the e-nose with a minimum handling of the sample is a fast and efficient alternative to these techniques. This rather new tool, simulating the behavior of the human nose, thus aroused our interest for application to dates. Materials and methods. Dates were harvested, in 2005, at the Tamar stage from nine date varieties, in Zagora, Morocco. They were frozen after harvest and sent by air to the laboratory of CIRAD (Montpellier, France). All data were collected at the same time. Five hundred g of dates were taken at random, pitted and cut into small pieces. After homogenization, an aliquot of 3.0 g was put into a 10-mL headspace flask and immediately sealed. Six replicates per sample were prepared for later electronic-nose analysis. An electronic nose (e-nose) from Alpha MOS, equipped with Metal Oxide Sensors (MOS), was used. Data were analyzed using Principal Component Analysis (PCA). The Discrimination Index (DI), created by Alpha MOS, was used to describe the discriminatory power of the groups’ separation. Alpha MOS considers that good discrimination and reliability are achieved for DI over 80%. Results. Discrimination indexes > 88% and means of the coefficients of variation obtained for each sensor < 4% demonstrate the high performance and good reproducibility of the e-nose. Conclusion. The e-nose is sensitive to date volatile emissions. All the date varieties studied were well separated. This fast screening technique, creating a specific olfactory fingerprint as a genuine identity card, could be used to follow changes in maturity, assure the identity of lots of dates and detect adulteration.

Introduction. Timing of management practices requires an understanding of pest population dynamics in given cropping systems. Our study was designed to establish the population trends of B. invadens in mango orchards and to determine if population fluctuations were reflected in fruit infestation levels during changes in mango phenology. Materials and methods. Bactrocera invadens flies were trapped weekly from February 2011 to November 2012, using methyl eugenol and DDVP (dichlorvos) insecticidal strips. Trapping was done in three mango orchards in the Luweero district of Uganda’s Lake Victoria Crescent. Mango fruit samples were incubated for the retrieval of puparia to calculate positivity (proportion of fruits infested) and fruit infestation indices (number of puparia per kg of fruit) for each stage of fruit maturity. Results. Mean trap catches of adult B. invadens varied significantly over the months (range : ~11 flies per trap per day (FTD) to over 590 FTD; P £ 0.0001). During each year, infestations peaked during June-July and January-February. Trap catches were higher in the major fruiting season compared with the minor fruiting season and were the highest when mango was at the physiological maturity and ripe stages. Fruit infestation and positivity were highest for fruit at the physiological maturity and ripe stages and lowest at the fruit set stage. Discussion. Our findings show that B. invadens is present year-round and all stages of mango fruit development are susceptible to attack. Thus, control measures should be implemented throughout the year and preferably started at fruit set to lessen fruit fly population build-up and damage to fruits.

Introduction. Mature green vanilla pods accumulate 4-O-(3-methoxy-benzaldehyde)-β-D-glucoside (glucovanillin), which, upon hydrolysis by an endogenous b-glucosidase, liberates vanillin, the major aroma component of vanilla. Little is known on the spatial distribution of aroma-generating phenolics, and the enzymes responsible for their liberation (β-glucosidase) and oxidation (peroxidase). We report here quantitative data with respect to these three components in relation to the anatomy of the pod. Furthermore, the spatial progression of oxidation is shown. Materials and methods. Mature green vanilla pods were analyzed for their contents of phenolics (HPLC), and β-glucosidase and peroxidase activities by spectrophotometric techniques using p-nitrophenyl glucoside and vanillin as substrates, respectively. Lipids were examined under fluorescence microscopy after Nile red staining. Oxidation development was observed on transverse slices of pods. Results and discussion. Phenolics, and β-glucosidase and peroxidase activities showed gradients of increasing-decreasing concentrations from the stem to the blossom end of pods. The β-glucosidase activity is distributed in between the placentae, mesocarp, and trichomes in a [7 / 2 / 1] proportion while that of peroxidase shows a [38 / 1] ratio in the mesocarp and placentae, and was absent from trichomes. Oxidation begins from the blossom end in the placentae, progressively invading the mesocarp and moving towards the stem end. Conclusion. The green mature vanilla pod is spatially heterogeneous for its phenolics, and β-glucosidase and peroxidase activities, its placentae playing an important role in the liberation of vanillin and its subsequent oxidation.

Introduction. Deux espèces de pitaya coexistent à la Réunion : Hylocereus undatus et H. costaricensis. Ces deux espèces, introduites, s'y reproduisent végétativement et, bien qu'elles fleurissent, ne produisent que rarement des fruits. Une étude a donc été menée pour vérifier les causes de l’improductivité de ces espèces et apprécier le rôle d’éventuels agents pollinisateurs. Matériel et méthodes. Deux modes de pollinisation libre (nocturne ou diurne) et deux modes de pollinisation contrôlée (croisement interspécifique manuel et autopollinisation) ont été comparés sur une parcelle plantée avec les deux espèces H. undatus et H. costaricensis intercalées. Les observations ont porté sur la viabilité du pollen, la nature des agents pollinisateurs, les conditions de pollinisation et la fructification. Résultats. Nous avons vérifié que l’absence de productivité des deux clones d’Hylocereus en conditions naturelles était due à leur auto-incompatibilité. En effet, aucune fécondation n’a été observée sur les 200 autopollinisations effectuées en 1999. Cette auto-incompatibilité n’est pas liée à une stérilité du pollen dont la viabilité in vitro s’est révélée satisfaisante. D'autre part, si les abeilles jouent un rôle dans la fécondation des deux clones, les fruits résultant de ces pollinisations libres sont significativement moins lourds que ceux issus d’une pollinisation manuelle croisée. Discussion et recommandations. Seule une pollinisation croisée et manuelle peut donc permettre aux deux clones d’Hylocereus présents sur l’île de la Réunion de produire des fruits de qualité. Un itinéraire technique de fécondation est proposé.

Introduction. Dacryodes edulis and Canarium schweinfurthii are two tropical multi-purpose trees in Cameroon which produce fruits (African pear and Black olive, respectively) for human consumption, which are marketed more and more on the national and international markets. This study aimed at characterising these two fruits starting from their physical and chemical properties. Materials and methods. Fruits were collected during the harvest peak in three agro-ecological zones of Cameroon. The physical properties measured were the weight, the length, the fruit circumference and the pulp thickness, while the chemical analyses included the moisture and protein, lipid and ash contents. Results. The fruits from the humid forest were largest (96 g), whereas the smallest came from the grassland (54 g). The highest pulp per fruit content (69% for the African pear and 57% for Black olive) was observed in fruits harvested in the humid forest zone. The strongest correlation (r = 0.25) between the fruit weight and that of pulp was observed for Black olive produced in the humid forest zone. The crude protein rate was highest (8%) in fruits from the humid forest, whereas that of the lipids (42%) prevailed in the semi-forest zone. Conclusion. The humid forest zone offers the best agro-ecological conditions for commercial production of the fruits of D. edulis and C schweinfurthii. These two fruits contain proteins and lipids in significant quantities and can, consequently, be used as alternative sources for these nutritive elements.

Introduction. Pitaya (Hylocereus undatus) is an exotic fruit species little known in Brazil and which needs basic studies about plant nutrition, propagation and physiology. Emphasizing the co-existence of juvenile and adult stages in the pitaya canopy, the plant is generally propagated by cuttings. Materials and methods. A completely randomized design with four treatments and five replications was adopted. Each treatment was represented by the part of the canopy from which the cutting was taken (upper, middle and lower cutting and cuttings from young plants). The following variables were registered: % cuttings with roots, % of live cuttings, root density, root diameter, root area, root length and root dry mass. Results were submitted to variance analyses, Tukey’s test at 0.01 probability error and simple correlation analysis. Results and discussion. The results indicated that the position from which the cutting is taken had a quantitative effect on rooting formation of pitaya cuttings. Juvenile cuttings presented 35% more cuttings with roots than adult cuttings. Root density, root area, root length and root dry mass depended on juvenility, the highest results being registered for juvenile cuttings, independently of the variable. Conclusion. Juvenile and adult stages co-exist in the pitaya canopy. Juvenility is an important rooting factor for red pitaya cuttings.

Introduction. Les aliments dits de disette, dont la plupart sont des fruits, sont identifiés un peu partout dans le monde tel qu’en Australie au Soudan, au Sénégal, en Amérique, au Sahel et au Tchad. Les travaux réalisés sur ces fruits portent souvent sur leurs valeurs nutritives. Au Sénégal, Maerua pseudopetalosa (Gil & Gil-Ben) De Wolf, espèce de la famille des capparidacées, fournit des fruits consommables aux populations autochtones pendant la période de soudure. Aucune étude scientifique n’a encore fait mention de la composition nutritive et de l’apport énergétique du fruit de cette espèce. Nos travaux ont permis d’évaluer l’apport en éléments nutritifs de son fruit. Matériel et méthodes. Des fruits de M. pseudopetalosa ont été récoltés à maturité au mois de juin 2007 et mai 2008 aux alentours des villages de Kéniéba et de Koussane, dans la région de Tambacounda au Sénégal. Les amandes ont été séchées et broyées pour les besoins des différents dosages. Les cendres, protéine, sucres, matières grasses, et sels minéraux ont été déterminés par des méthodes d’analyse classiques normalisées. Résultats et discussions. Nos résultats ont montré que le fruit de M. pseudopetalosa était riche en fer (26,8–45,9 mg·kg–1), en potassium (1098–1342 mg·100 g–1) et en protéine (19,26–22,06%). Cependant, le profil d’acides aminés témoigne d’une médiocre qualité nutritionnelle de sa protéine. Conclusion. Il ressort de cette analyse que le fruit de M. pseudopetalosa constitue malgré tout une excellente source de nutriments et peut valablement combler certaines carences, surtout en période de disette.

Introduction. A study on postharvest treatments of wild peppers was carried out in Madagascar with the aim of describing the local practices and measuring their impacts on the quality of the products. Materials and methods. Four distinct pepper production systems (PPS) were observed, described and compared in two separate areas in East Madagascar. Major quality characteristics (piperine and essential oil) of the peppercorns were assessed in samples collected in the four systems. Results and discussion. Two main postharvest processes (dry and wet) were identified. The wet process differed from the dry one in that it involved two specific operations, blanching and sweating. The processes influenced the color of the pepper. Piperine contents were not affected by any of the pepper production systems, whereas essential oil contents were reduced by up to 27% by the wet process. After processing, piperine contents were up to eight times lower, whereas essential oil contents were up to six times higher than the specifications of the standard ISO 959-1 for black pepper ready for commercialization. Conclusion. Two main processes (dry and wet) for treatment of peppercorns in Madagascar were identified and described. The dry process, with two steps less, appeared to be easier to implement and more respectful to the product. Improving maturity control and processing according to the quality expected by the markets will be necessary to promote Malagasy peppers.

Introduction. Bananas are harvestedat the green preclimacteric stage prior to sale. The time betweenharvest and the initiation of the natural ripening process is calledgreen life. Black Leaf Streak Disease and Sigatoka Disease are themain foliar diseases affecting banana production. Sigatoka Disease (SD)is due to Mycosphaerella musicola, which frequently causesearly ripening in commercial banana plantations, considered as animportant source of damage. Our work aimed at determining the effectivenessof the removal of necrotic leaves, one month before harvest, onrecovering banana quality arising from SD-infested plants. Materialsand methods. Banana plants (totaling 80) at the floweringstage were selected in an experimental plot. These plants were dividedinto two groups of SD infestation levels: level 1 (Severity Indexat flowering < 10%) and level 2 (Severity Index at flowering > 25%).We divided each group into two treatments: a treatment with no necroticleaf removal and a treatment with necrotic leaf removal. Fruitswere harvested at the same physiological age, at 900 degree-days. Fruitquality was characterized by weight, diameter, % of ripe fruit inthe field and fruit green life. Results. Our resultsshowed that the removal of necrotic leaves causes a reduction insize parameters but leads to a strong reduction in SD effects onthe fruit maturity, thereby preventing premature ripening. Bananaplants whose necrotic leaves were removed produced fruit with a verylong green life. Discussion. Removal of necrotic leaves allowsthwarting the negative effect of SD on fruit physiology. This showsthat the presence of necrosis during the last month of fruit growth isresponsible for this fruit physiological modification characterizedby early ripening. Conclusion. Removal of necroticleaves one month before the date of harvest may be a technique thatcan limit production losses when the infestation level by SD ishigh.

Introduction. The determination of an adequate container volume that combines rational use of substrate with maximization of vegetative growth is very important to optimize citrus nursery tree production. This experiment aims to evaluate the influence of container volumes on vegetative growth of citrus nursery trees. Materials and Methods. Pera sweet orange nursery trees [Citrus sinensis (L.) Osbeck] budded on Rangpur lime (Citrus limonia Osbeck) were produced in six container volumes [(3.0, 3.8, 4.5, 4.6, 5.0 and 5.8) L], with the respective container dimensions of [(20 × 32, 20 × 35, 22 × 32, 22.5 × 35, 25 × 32 and 25 × 35) cm]. Another 5.0-L container studied had the dimensions of 20 cm x 40 cm. Commercial substrate was composed of Pinus bark and a controlled-release fertilizer was used. Parameter evaluation started after moving the rootstocks from seedling trays, 3.5 months after sowing, to plastic containers and continued until nursery trees reached one year old. The studied parameters were shoot height, diameter and leaf area of rootstocks and nursery trees, bud take percentage and scion and root dry matter of nursery trees. Results and discussion. The development of Rangpur lime plants was not affected by any treatment until budding. The largest container volumes induced faster and more vigorous vegetative development of Pera sweet orange nursery trees budded on Rangpur lime. A 5.0-L container volume could be indicated as a technical and economical option for the production of containerized citrus nursery trees.

Introduction. Calcium chloride (CaCl2) treatment has been shown to increase the shelf-life of fruits, mainly through making cell walls less accessible to pathogens and softening enzymes. Materials and methods. bananas of four cultivars [`Ambon' (AAA), `Embul' (AAB), `Kolikuttu' (AAB) and `Seenikehel' (ABB)] were dipped in or pressure infiltrated with 4% CaCl2. To determine the effect of exogenous ethylene on treated fruits, they were ripened with exogenous ethylene. Ca2+ in cell wall fractions were monitored by atomic absorption spectrophotometry. Cup plate assays were performed to determine pectinase activity. Results and discussion. Pressure infiltration accelerated ripening and disease, and reduced firmness (P < 0.05). However, when exposed to ethylene, CaCl2 pressure-infiltrated bananas were insignificantly firmer than distilled water-infiltrated and ethylene-ripened bananas, showing a significant interaction (P < 0.05) between infiltration treatments and ethylene ripening. There was no consistent increase in covalently bound pectin of cell walls as seen in fruits that respond positively to CaCl2. Firmness reduction and ripening acceleration by Ca2+ treatment cannot be explained if polygalacturonase (PG) (known to be inhibited by Ca2+) was the dominant pectinase. Enzyme assays gave evidence of PG activity. When ammonium oxalate (known to bind Ca2+) was eliminated from the test medium, pectinase activity increased with increasing pH (pH 5 to 9). The presence of a pectinase enzyme which exhibits activity in the presence of Ca2+ is apparent. Conclusion. Ca2+ does not appear to influence cell wall structure of bananas but appears to influence ripening physiology.

Introduction. The grapefruit tree has a long production period. In the Jordan Valley, harvest lasts from November to March. Many Jordanian farmers tend to harvest their fruit early to get high prices, regardless of its quality. Thus, the effect of the harvesting date on fruit quality of grapefruit cv. ‘Red Blush’ was evaluated under Jordan Valley conditions for two seasons, 2002 and 2003. Materials and methods. Fruit quality of uniform 25-year-old grapefruit cv. ‘Red Blush’ trees budded on sour orange rootstock was studied during the 2002 and 2003 seasons. Fruits were harvested from October 15 in both seasons with 15-day intervals with a total of eight harvests. The studied data were total soluble solids (TSS), titratable acidity (TA), the [TSS/TA] ratio and juice percentage. Results and discussion. Fruit total soluble solids and fruit juice percentages were at a minimal level during early harvesting dates and increased with time, reaching the maximum level on January 1 for TSS and January 15 for fruit juice percentage in the first season and on December 15 and February 1, respectively, in the second season, after that TSS decreased. Fruit titratable acidity values were at maximal levels during early harvesting dates (October 15) and decreased with time, reaching the minimum level on February 1 in the first season and on January 15 in the second season. The [TSS/TA] ratio ranged from 5.5 to 6.0 between January 1 and February 1 in the first season, and between December 1 and January 15 in the second season. Conclusion. Our study displayed that Jordan Valley growers are harvesting their grapefruits much too early to provide acceptable eating quality fruits to local markets.

Introduction. This protocol describes a method for obtaining protoplasts from banana leaves, calli and cell suspensions, and their sustainable development via somatic embryogenesis from embryogenic cell suspensions. The principle, key advantages, starting plant material, time required and expected results are presented. Materials and methods. This part describes the required laboratory materials, and media preparation for protoplast production and culture. Results. The first protoplasts may be seen after 30 min of incubation in enzyme maceration. With protoplasts from embryogenic cell suspension, complete development into a whole plant, through somatic embryogenesis, is observed in 12 weeks. The first cell divisions occur on feeder layers 3–8 days after protoplast plating. Proembryo formation is observed 14–21 days after initiation of protoplast culture. The transfer of derived embryo plantlets, at 8–10 weeks after protoplast plating, onto growth regulator-free medium, leads to plant rooting and elongation.