Introduction. Alternative propagation techniques must be developed in order to reduce the time required to evaluate germplasm in citrus breeding programs. Our study investigated the rooting capacity and initial plant development of different citrus somatic hybrids that have potential for use as rootstocks. Materials and methods. Eleven different hybrids were tested. Cuttings of these plants were placed in trays inside an intermittent mist chamber. After 100 days, the percentage of cuttings with callous and with roots, average number of roots, and root length were recorded. The cuttings were then transferred to plastic bags and kept in the greenhouse. The flush length was recorded monthly. After 7 months, the percentage of plants suitable for grafting and the average scion and root dry mass were calculated. Results and discussion. [Caipira sweet orange + Cleopatra mandarin], [Caipira sweet orange + Volkamer lemon], [Rangpur lime + Sunki mandarin] and [Rohde Red Valencia sweet orange + Volkamer lemon] hybrids developed many roots, while [Caipira sweet orange + Volkamer lemon] and [Rohde Red Valencia sweet orange + Volkamer lemon] hybrids showed the best development after the transplant.

Introduction. Aux Antilles, l’introduction de la jachère, dont l’utilité dans la maîtrise du parasitisme tellurique est avérée, est à l’ordre du jour du fait de l’explosion du parasitisme lié à la monoculture bananière. Comme cette pratique est soutenue par la recherche et les pouvoirs publics, l’étude entreprise a eu pour but d’analyser les écarts entre les préconisations portées par un dispositif institutionnel et les pratiques des agriculteurs afin d’identifier à quelles conditions les pratiques de jachère peuvent être mises en place. Méthodologie. Les déterminants et fonctions attribués aux jachères ainsi que les freins ont été abordés à partir d’enquêtes auprès d’exploitants. Celles-ci ont permis de recueillir entre autres les variables nécessaires à la caractérisation des règles de décision en matière de gestion des assolements et de contraintes endogènes à l’exploitation. Le choix des exploitations enquêtées nous a conduits à étudier les pratiques de jachères dans le cadre d’une typologie d’exploitation distinguant, parmi 42 exploitations étudiées, les types, « Diversifié », « Bananier familial » et « Bananier entrepreneurial ». Ces types sont représentatifs des exploitations de moins de 20 ha. Le cas de la jachère en Guadeloupe. Les résultats ont montré que la jachère est présente chez plus de la moitié des exploitants enquêtés. Sa situation varie avec les types d’exploitation ; elle est soit subie, soit intégrée dans les systèmes de culture. Les modes de conduites sont fonctions des objectifs des exploitants : assainissement, pâturage, gestion de la trésorerie, etc. Les freins au développement des jachères sont nombreux : manque de surface, difficulté de raisonner à long terme, manque à gagner sur une terre qui ne « produit » pas, etc. Cependant les calculs économiques sur des systèmes de culture incluant la jachère montrent que leurs marges brutes sont supérieures à celles trouvées pour des bananeraies continues et pérennes. La principale contrainte est rencontrée au moment du changement de système cultural lorsque l’exploitant doit faire face à une terre qui ne procurera un supplément de rendement que deux ans plus tard. Discussion et conclusion. Notre étude a mis en évidence que la multiplicité des pratiques de jachère, pertinentes au regard des objectifs des exploitants, n’est qu’en partie prise en compte dans les dispositifs institutionnels existants. Cela appelle une diversification des référentiels techniques.

Contexte et présentation du projet. Après un bref historique et un aperçu général de l’arboriculture fruitière en Polynésie française, le fonctionnement et les opérations programmées sur 3 ans d’un projet d’appui mené de 2002 à 2005 sont présentés. Réalisation. Les cinq thèmes principaux d’intervention sont successivement décrits : amélioration du matériel végétal ; recherches d’accompagnement ; formation, vulgarisation et encadrement : volet complété par la rédaction de documents techniques ; missions d’appui et stages ; démarche qualité et organisation de la profession, complété par un volet de valorisation des produits par transformation. Les résultats et les moyens utilisés sont analysés. Discussion et conclusion. Les avantages et inconvénients rencontrés dans la réalisation du projet sont discutés et permettent de proposer quelques améliorations dans la mise en œuvre de projets analogues.

Introduction. A study was conducted in India to assess the efficiency of 32P uptake and the feasibility of intercropping using land-use efficiency parameters in a banana-based intercropping system. Materials and methods. Absorption of 32P applied to plants in five-crop, two-crop and sole-crop systems involving banana Musa AAB (‘Mysore’), ginger (Zingiber officinalis Rosc.), turmeric (Curcuma longa L.), cassava (Manihot esculenta Crantz.) and elephant yam (Amorphophallus campanulatus Blume.) was studied in field trials. The experiment was conducted for two years. During the first year, the main crop was planted during October, the main planting season for banana in India, and the intercrops were planted in early May of the next year. In the second year, both the main crop and intercrops were planted in May. Results. Radiophosphorus applied in the active root zone of one of the component species in the mixed crop system was found to be absorbed not only by the treated plant but also by the neighboring plants. Absorption by banana was prevalent. Differential effects of competition were manifested as observed by the relative uptake of 32P. Lower relative uptake of 32P was observed in the main crop banana when simultaneous planting of intercrops was done. Ginger and turmeric were not affected in relation to planting at different stages of the main crop, whereas cassava and elephant yam showed lesser relative 32P uptake when planted later, confirming that different crops in the mixed crop system react differently. Conclusions. The efficiency of different crops in terms of uptake varied with the system of planting. The higher relative efficiency of 32P uptake in a multiple cropping system points to an improved efficiency of uptake and higher dry weight on a per plant basis. It confirms the efficiency and feasibility of the cropping system. Economic analysis emphasizes the concept and proves the viability of the system.

Introduction. Competition between plants on a mat (intramat) and between plants on different clumps (intermat) is quite common in crops such as banana. A study was therefore undertaken to know the extent of intramat and intermat competition using isotopic techniques. Materials and methods. The competition between plants in a mat and between mats were recorded in a combination of three spacings and five physiological phases of sucker retention by giving 32P to an experimental plant using soil injection techniques and monitoring the levels of recovery. The recovery of the isotope was recorded in the applied plant and its daughter (intramat) and in the neighboring border plant and its sucker (intermat). Results. The study revealed that, when 32P was given by soil injection techniques to one plant, it could be recovered in the border plant and its sucker during both years of study. In the first year, activity in initial samplings in border clumps were the highest, with the widest spacing in the experimental plant showing the highest recovery, but a differential pattern of recovery was observed at different samplings in the border clumps. In the irrigated crop of the second year, the highest recovery was observed at the closest spacing in both the experimental and border clumps. With respect to sucker retention at definite physiological phases, the recovery was the highest at the late vegetative phase, the flower bud initiation and the shooting phase. The recovery in the mother plant and its sucker and the border plant and its sucker studied separately gave a measurement of the intramat competition. Conclusion. The differential nature seen with retention phases confirms the requirement and intensity of activity with defined physiological phases and the overall need to evaluate and redefine recommendations, taking into consideration the critical physiological phases.

Introduction. Arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) can be considered important rhizospheric beneficial microorganisms. Their use as biocontrol strategies against soilborne pathogens such as nematodes should be taken into account. However, optimal management of soil microbiota communities is not easy because of the high specificity involved in these types of interactions. The aim of our study was to determine whether the combined inoculation of two AMF species and a Bacillus consortium based on three strains previously described as PGPR in other crops were able to reduce nematode infection and damage on papaya. Materials and methods. Papaya seedlings were inoculated with two AMF isolates (Glomus mosseae or G. manihotis) at the beginning of the nursery phase. Once the mycorrhizal symbiosis was established, a Bacillus consortium was applied. Nematode inoculum was applied 20 d after transplanting to individual pots. Plants were harvested 160 d after nematode inoculation. Results. In terms of plant development and nutrition, benefits due to AMF inoculation persisted in the presence of PGPR. However, the effect of dual inoculation was different, depending on the Glomus species. This positive effect was also evident in plants with nematode. Meloidogyne infection was significantly reduced in mycorrhizal plants. However, the addition of PGPR does not seem to improve the results of AMF single treatments in terms of nematode infection. Conclusion. Dual application of AMF and PGPR must be considered for papaya threatened by the root-knot nematode, although a previous screening should be done in order to select the best microbe combination to optimise results.

Introduction. The objective of the present paper was to evaluate the effects of N, P and K, and their interactions, on fruit yield and quality of two sweet orange varieties, Valencia and Pêra, grown on tropical soils in the State of São Paulo, Brazil, over four seasons. Materials and methods. Two experiments were set up in a fractional factorial design of the ½ (4 × 4 × 4) type, with four rates of N [(30, 100, 170 and 240) kg·ha–1·year–1], P [(9, 27, 45 and 63) kg·ha–1·year–1)] and K [(24, 91, 158 and 225) kg·ha–1·year–1] applied to the soil surface during the rainy season. Functions of the type y = b0 + b11 N + b11 N2 + b2 P + b22 P2 + b3 K + b33 K2 + b12 NP + b13 NK + b23 PK were fitted for dependent variables: fruit yield and mass, juice content, and total soluble solids and acidity concentrations. Results. Maximum yield of Pêra and Valencia was attained, respectively, with N rates of (189 and 193) kg·ha–1. Fruit yield response to P and K fertilization for both cultivars was dependent on soil nutrient availability. Fruit size of Valencia trees was markedly affected by rates of K over 225 kg·ha–1. Yield of soluble solids per box of fruits (40.8 kg) decreased as leaf K concentration varied from (10 to 12) g·kg–1. Conclusion. Soil testing and leaf analysis play an important role in defining fruit yield and quality for citrus trees. The best nutritional program may vary depending on the destination of fruit to either juice production or the fresh market.

Introduction. L’orange (Citrus aurantium sinensis) est une source de composés bioactifs : vitamines C et E, flavonoïdes (flavanes et flavanones glycosylés et polyméthoxylés). Pour valoriser les déchets des peaux d’orange, nous avons mesuré l’activité antiradicalaire du jus et des peaux sèches et fraîches de cinq variétés d’orangers de Tunisie afin d’évaluer leur concentration en composés antioxydants utilisables dans l’industrie. Matériel et méthodes. Le pouvoir antiradicalaire du jus et des extraits des peaux a été évalué en suivant, en fonction du temps, la disparition du radical stable DPPH• par spectrophotométrie d’absorption UV-visible à 515 nm. L’activité antiradicalaire mesurée a été exprimée en concentration efficace (CE50). La détermination du volume V50 de vitamine C d’une solution d’acide ascorbique de concentration connue et d’un volume V50 des extraits de jus et des peaux sèches et fraîches d’orange a permis d’estimer la concentration molaire et massique de vitamine C équivalente dans les extraits. Résultats. Les jus d’orange contiennent environ 400 mg·L–1 d’équivalent de vitamine C. Dans le cas de réactions très rapides avec le radical DPPH•, la totalité de l’activité antiradicalaire peut être attribuée à la vitamine C. Dans le cas de réactions plus lentes, en plus de la vitamine C, ce sont les polyphénols (citroflavonoïdes) qui contribuent à l’activité antioxydante totale. Les extraits méthanoliques des peaux fraîches (flavédo) contiennent plus de vitamine C que les extraits de peaux sèches. Conclusion. Les peaux d’oranges constituent d’immenses sources d’antioxydants qui peuvent trouver leur application dans différents domaines : agroalimentaire, cosmétique, pharmaceutique et autres.

Introduction. The yellow passionfruit is consumed mainly as juice and is well accepted around the world. The nutritional state of the plant influences yield and fruit quality. We studied the particular effect of potassium nutrition on the quality of yellow passionfruit. Materials and methods. The experiments were conducted in a greenhouse at the Federal University of Viçosa, in Brazil, outlined in a randomized block design. The treatments were five concentrations of K [(1, 2, 4, 6 and 8) mmol·L–1] in a modified nutritive solution of Hoagland and Arnon. The experimental unit consisted of one plant in a 20-L pot containing washed sand. The plants were irrigated by a circulating hydroponic system. The nutrients were re-added to the solution based on its electric conductivity and on the K content in each solution. Results and discussion. The K supply increased yield and average fruit weight up to the concentration of (6.43 and 6.24) mmol·L–1, respectively, and linearly increased the number of seeds per fruit, thickness and relative water content of the pericarp and vitamin C content. The total titratable acid content increased according to a square equation, with the maximum point at 5.27 mmol K ·L–1. The pulp percentage, pH and total soluble solids content were not influenced by K doses. Conclusions. The increase in K supply promoted yield and fruit quality. At 90% of the maximum yield, the fruits had adequate quality traits.

Introduction. Still practically unknown in the mid-1990s in Europe, pitahaya (Hylocereus spp.) is now a full member of the ‘small exotic fruits’ category in shops. Nevertheless, these species are not very well known. The aims of our work were first to evaluate thoroughly the literature currently available on Hylocereus and secondly to supplement this review by agronomic works not yet published. Knowledge of Hylocereus. The study includes a presentation of the origin, botany, morphology and floral biology of the principal species cultivated within the Hylocereus genus and suggests a key for determination. Cultivation techniques. The agronomical practices used in Hylocereus orchards are broached: multiplication, cultivation practices (supports, density, pruning, mineral nutrition, irrigation, etc.), pollination and harvest. Pests and diseases are cited too. Physico-chemical composition of fruits. This work draws up a review of different studies regarding pitahaya composition, micronutrients and pigments. Post-harvest and processing. The life of the fruit after harvest (conservation and storage life) is approached as well as the various possibilities of processing. European market. The European market is analyzed for the various cultivated species of Hylocereus (imported quantity, market segment, origin of production, etc.) and its evolution prospects are evoked. Conclusion. Our review highlights the fact that the interest shown in these pitahayas is recent and, for these reasons, more detailed knowledge on these species is required (agronomic, genetic and technological).

Introduction. Plant regeneration from in vitro culture of adult citrus tissue may help in early evaluation of important horticultural characteristics of genetic material from breeding programs, which incorporate biotechnological tools. Our research aimed to optimize in vitro culture conditions that could lead to the maximum plant regeneration through organogenesis of ‘Bahia’ sweet orange (Citrus sinensis L. Osbeck) in explants (internodes and foliar disc segments) collected from adult plants grown under greenhouse conditions. Materials and methods. Organogenesis was induced in internodes on DBA3 culture media supplemented with BAP at (0.0, 1.0, 2.0 and 3.0) mg·L–1 combined with NAA (0.5 mg·L–1), and in foliar discs on culture media with BAP at (0.0, 0.5, 1.0, 1.5 and 2.0) mg·L–1 combined or not with NAA (0.5 mg.L–1). Results and discussion. The concentrations of (1.0, 2.0 or 3.0) mg·L–1 of BAP combined with 0.5 mg·L–1 of NAA induced in vitro organogenesis in internodes of ‘Bahia’ sweet orange. The use of foliar discs was not efficient for adventitious organogenesis.

Introduction. Mango (Mangifera indica L.) production is rising in various subtropical zones throughout the world. The main polyembryonic rootstocks used by growers in South-East Spain are Gomera 1 and Gomera 3 (from the Canary Islands) and the most commonly used cultivars are Osteen and Keitt (from Florida, US). In this marginal environment for mango growing, it is important to determine the different rootstock qualities in order to optimise fruit production. The objective of our study was to evaluate the performance of mango cv. Osteen and Keitt on the two aforementioned rootstocks, as measured by fruit yield, scion growth and mineral nutrition. Materials and methods. A 3-year study was conducted in a mature mango orchard (14 years old) of a total of 24 trees, where eight were grafted onto cv. Osteen, another eight onto Keitt (four trees with each of the G1-Ost, G3-Ost, G1-Kt and G3-Kt combinations) and eight were ungrafted rootstocks. Fruit yield and pomological characteristics were evaluated by measuring fruit length, width and weight. Height and canopy diameter, as well as the trunk circumference of the tree, were recorded. Throughout the study period, chemical foliar measurements were taken from all trees. Results. Fruit yield in G1-Ost and G3-Kt trees proved significantly higher than that in the others. The fruit weight and length with the G3-Kt combination were greater than those with G1-Kt. Both cultivars grafted on Gomera 3 rootstock had the highest height and canopy volume. The tree-size data confirmed the vigorous feature of the Gomera 3. The N and P foliar concentration was significantly higher for Gomera 3 than for Gomera 1 in both cultivars. The K concentration was higher in G3-Kt leaves than in G1-Kt ones, but higher in G1-Ost than in G3-Ost. The leaf Mn and Cu concentrations with G3-Kt significantly exceeded those of G1-Kt. Conclusion. The height, trunk cross-sectional area, and canopy volume and diameter proved to be the greatest with Gomera 3, reflecting the vigour of this rootstock. The combinations G1-Ost and G3-Kt registered the highest fruit yield, offering promising possibilities for boosting subtropical productivity in mango.

Introduction. The severe impact of papaya bacterial canker in the West Indies justified launching a program to transfer the genetic resistance/tolerance identified in local germplasm to good-quality cultivars. As a first step, a germplasm collection from the Caribbean was gathered and its morphological and genetic diversity assessed. Materials and methods. The total sample included 50 accessions from the Lesser Antilles, Cuba, Venezuela, Costa Rica and Hawaii. Morphological data from a subsample of 29 accessions were submitted to analysis of variance, principal component analysis and Neighbor-Joining cluster analysis. Nine isozyme systems were tested, and the corresponding data were processed for cluster analysis and genetic parameters, including the fixation index, diversity indices and heterozygosity. Results. Eighteen of the 47 Caribbean and Venezuelan accessions exhibited hermaphroditism. Venezuelan accessions displayed the widest morphological diversity, while those from Barbados were distinguished by fruit quality. Sexual type affected leaf and flower traits. Cluster analysis shows little morphological differentiation between origins, with the relative grouping of the accessions from Guadeloupe or Barbados. Only four isozyme systems were polymorphic, producing 34 distinct zymotypes, with a relatively high heterozygosity and a particular diversity in Venezuela, Guadeloupe and Barbados. Geographic structuration appears limited in the cluster analysis among individuals; however, it is clearer when considering the six best-represented populations, with one cluster representing Venezuela, Trinidad and Barbados, and one for Guadeloupe, Martinique and Grenada. Discussion. The low level of fixation is attributed to dioecy and to the low level of selection. The relative isolation of island populations has favored geographic differentiation, albeit limited. The differentiation between the good-quality germplasm from Barbados and the tolerant populations from Martinique and Guadeloupe encourages the development of a marker-assisted introgression scheme.

Introduction. Le karité a une fructification aléatoire. L’objectif de notre étude a été de tester la technique d’incision annulaire comme outil de contrôle de cette fructification irrégulière. Matériel et méthodes. En août 2003, une incision annulaire portant sur les trois quarts du pourtour d’une branche a été effectuée, jusqu’à l’aubier, sur 29 karités du terroir de Bondoukuy (Burkina Faso) ; une branche de chacun de ces mêmes arbres a servi de témoin. En 2004, un essai factoriel d’incision a été entrepris ; il a porté sur deux sites de ce même terroir, deux périodes de traitement (fin août et fin novembre), trois ampleurs d’incisions (50 %, 75 % et 100 %) et cinq karités utilisés par traitement. Ce sont donc 60 karités multicaules qui ont été étudiés, un des troncs de chacun d’eux servant de témoin. La proportion de rameaux florifères (%rFl) et le nombre de fleurs (nFl) et de fruits (nFr) formés par rameaux traités et témoins ont été comptabilisés puis analysés. Résultats. Par rapport aux branches témoins, l’incision annulaire a accru de 17 % le (%rFl), 54 % le (nFl) et 100 % le (nFr) par rameau. Les périodes et ampleurs d’incision testées n’ont pas montré de différences entre elles, mais elles ont permis aux branches traitées d’obtenir un (%rFl) supérieur à celle des branches témoins. Quelle que soit la variable considérée, il est apparu une différence de performances de reproduction entre les karités des sites testés ; l’efficacité de l’incision annulaire serait donc liée aux conditions édaphiques de développement de l’arbre. Discussion et conclusion. La technique d’’incision annulaire peut donc être utilisée pour contrôler l’irrégularité de la fructification du karité. Néanmoins, des études complémentaires se révèlent indispensables pour déterminer l’effet de la période de l’incision sur le grossissement et la composition chimique des fruits.

Introduction. The emergence of P. caerulea L. seeds was studied for the first time, in order to obtain useful information for cultivation of this plant with ornamental, edible and medicinal values. Materials and methods. Different treatments (aril removal, mechanical and chemical scarification and combinations of them) were performed on fresh seeds before sowing. The treatments simulated different paths that the seeds may follow in nature in this ornithochorus species, those which small growers could reproduce before cultivation. Seed emergence was recorded periodically for 16 months in a greenhouse. Seed emergence initial time, percentage and speed were calculated. Results and discussion. Seeds immersed in hydrochloric acid (chemical scarification) did not germinate, but the rest of the treatments were successful. Emergence percentages were low in most of the treatments and speed was slow in all of them. The minimum seed emergence initial time was 25 days. The curve of the accumulated number of seeds emerged followed an oscillating sigmoid pattern. Conclusion. It is suspected that dormancy exists, which will be dealt with in another paper.

Introduction. À l’instar d’autres secteurs de produits destinés à l’alimentation humaine, une restructuration profonde de la filière ananas martiniquaise s’accomplit pour répondre à de nouvelles exigences de sécurité alimentaire et de protection de l’environnement : management de la qualité sur l’ensemble de la filière et exploitation de nouvelles variétés d’ananas. À partir de l’analyse des pratiques actuelles, les auteurs ont évalué les besoins de changements, puis proposé quelques outils pour la mise en œuvre d’un système de production. Matériel et méthodes. Des enquêtes ont permis de connaître les pratiques et stratégies actuelles des producteurs d’ananas et d’établir une typologie des exploitations. Un comité de pilotage associant des représentants de l’ensemble de la filière élabore le système de management de la qualité en se basant sur la norme Agriconfiance®. De nouvelles variétés sont en cours d’évaluation pour couvrir au mieux les besoins en ananas de qualité pour la transformation ou pour la vente en frais. Résultats et discussion. Les écarts constatés entre recommandations et pratiques culturales sont apparus très variables mais souvent importants : trop d’intrants en général, soit les pesticides, soit les engrais, soit les deux. Le système de management appliqué repose sur un contrat entre une coopérative et les producteurs. Les règles de qualité sont fixées dans deux cahiers des charges, l’un concernant la qualité de la production au champ, l’autre, la qualité du fruit pour l’usine. Un système de traçabilité à l’échelle de la parcelle a été élaboré. Il permet la prévision et l’enregistrement de toute activité liée à la production, avec la parcelle comme unité de base. Enfin, de nouvelles variétés hybrides sélectionnées par le Cirad ont pu être testées dans le nouveau processus de transformation de la coopérative, donnant de meilleurs résultats que l’ancienne variété Cayenne lisse. Conclusion. La restructuration de la filière ananas en Martinique résulte avant tout de considérations économiques. Cette démarche a conduit au développement d’un programme global d’assurance qualité, avec instauration d’un système de traçabilité parcellaire, destiné à garantir la sécurité alimentaire. Une homogénéisation des pratiques culturales est nécessaire, en se rapprochant des recommandations pour améliorer la qualité. Elles pourraient être rassemblées dans un guide de culture spécifique. L’adoption de nouvelles variétés d’ananas permettant d’obtenir de meilleurs rendements de transformation ainsi qu’une qualité accrue du produit frais ou transformé sera aussi un élément déterminant du succès de la démarche.