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Ce chapitre sur l'ananas aborde les thèmes suivants : morphologie végétale (tige, feuilles, racines, inflorescence, fruit, multiplication végétative), taxonomie (les #Bromaliaceae#, évolution de la classification des ananas, le genre Ananas et ses espèces), origine et évolution

A better knowledge of factors organizing crop genetic diversity in situ increases the efficiency of diversity analyses and conservation strategies, and requires collaboration between social and biological disciplines. Four areas of anthropology may contribute to understand the impact of social factors on crop diversity: ethnobotany, cultural, cognitive and social anthropology. So far, most collaborative studies have been based on ethnobotanical methods, focusing on farmers' individual motivations and actions, but overlooking the effects of farmer's social organization per se. We analyze how social anthropology, analyzing intermarriage, residence and seed inheritance, can contribute to studies of crop genetic diversity in situ, by considering crop varieties as social objects and by designing socially based sampling strategies. Because seed exchange is built upon trust, seed systems are embedded in a pre-existing social structure and centripetally oriented as a function of farmers' social identity. The strong analogy between farmers' cultural differentiation and crop genetic differentiation; both submitted to the same vertical transmission processes, allows proposing a common methodological framework for social anthropology and crop population genetics, where the classical interaction between genetic and environmental factors, G x E, is replaced by a three-way interaction G x E x S, with "S" designating the social differentiation factors.

The pineapple, Ananas comosus var. comosus, a major contribution from Precolombian civilizations to world horticulture, evolved from the wild A. comosus var. ananassoides in the Guianas and further developed into a wide range of large-fruited cultivars in the upper Amazon, more than 3,500 thousands years ago, before diffusing to all tropical Americas in prehistoric times. As wild relatives and primitive cultigens belong to the botanical varieties of A. comosus and to the wild tetraploid A. macrodontes, reproductive barriers are inexistent or limited to differences in ploidy. The exploitation of wild and primitive germplasm is promising for pineapple breeding; however, it is limited by the difficult characterization and introgression of resistance traits. In comparison, the development of ornamental cultivars appears straightforward, as interesting traits are much easier to manipulate. Other uses, as high-quality fiber production and pharmaceutical treatments, open new commercial perspectives. Ananas germplasm collections clearly need further investigation to realize their full potential.

De par leurs adaptations climatiques, les espèces étudiées d'Entandrophragma (E. angolense et congoense, E. candollei, E. cylindricum, E. utile) sont fortement différenciées des autres espèces du genre, lesquelles occupent des bas-fonds périodiquement inondés (bassin du Congo), des habitats de montagne (Grands-Lacs) ou des régions de climat plus sec et contrasté (Angola et Afrique australe). Pourtant, l'étude de leur distribution et de leurs enveloppes climatiques ne montre que très peu de différenciation. Seule E. angolense se distingue par une plus grande plasticité. Ces résultats, ainsi que les résultats des premières analyses phylogénétiques, suggèrent un cas de spéciation sympatrique récente. L'omniprésence du caractère décidu dans le genre, ainsi que l'existence d'espèces sous des climats plus secs (précipitations, saison sèche), indiqueraient que ces espèces ont pénétré relativement récemment en forêt humide. Elles ont donc colonisé des régions à pluviométrie intermédiaire, en dehors des refuges forestiers supposés. Les espèces de Dacryodes étudiées présentent aussi des fortes similitudes d'adaptations climatiques, avec un fort recouvrement des aires de distribution potentielles. Ces dernières sont centrées sur le Gabon et le Sud du Cameroun, en particulier dans les régions de refuges forestiers supposés. La plupart des espèces présente une répartition limitée à la région floristique dite de " basse Guinée ". Seuls D. klaineana et D. edulis (espèce domestiquée) ont pu franchir la LVC et le couloir du Dahomey. Les Dacryodes sont adaptées aux forêts humides, en particulier à une humidité atmosphérique élevée (piedmonts et versants au vent, couverture nuageuse durable). Cette faible différenciation dans l'adaptation suggère une spéciation sympatrique probablement récente, contrastant avec une radiation en allopatrie pour les représentants sud-américains du genre. (Texte intégral)

Dans le genre Entandrophragma, l'étude a été centrée sur les cinq taxons rencontrés en forêt dense humide de terre ferme et de basse altitude (E. angolense et congoense, E. candollei, E. cylindricum, E. utile). Les autres espèces du genre sont situées dans des milieux forestiers (deux d'entre elles) et, souvent, dans le domaine des savanes et forêts claires. Les premières analyses génétiques montrent que ces taxons de forêts denses humides sont proches, plus particulièrement E. cylindricum et E. utile. Deux taxons, placés en synonymie par certains botanistes, E. angolense et E. congoense, n'ont pas pu être différenciés à ce stade. Concernant le genre Dacryodes, les premières analyses phylogénétiques des espèces africaines indiquent qu'elles sont également proches génétiquement ; toutes sont des espèces de forêts denses humides, y compris celles de la région congolaise. Ainsi, les mitotypes dominants (NAD712) pour D. buettneri, D. edulis, D. klaineana, D. igaganga, D. macrophylla et D. normandii sont identiques. Un deuxième mitotype est commun à D. buettneri et à D. edulis. Les autres mitotypes sont rares. L'ADN chloroplastique (rpl16) montre une plus grande variation mais les données sont moins nombreuses. On remarque une très forte différenciation entre deux chlorotypes rencontrés chez D. edulis, même au sein d'une même population cultivée. Des analyses génétiques supplémentaires sont encore nécessaires afin d'évaluer plus précisément les relations et les distances génétiques entre les espèces telles que définies par les botanistes. (Texte intégral)

Modéliser les aires de répartition pourrait s'avérer d'un grand intérêt pour planifier la conservation et l'utilisation durable de la biodiversité. Ma1heureusement, dans les pays tropicaux, le manque de données limite encore fortement la validation et l'usage des modèles. En utilisant diverses sources issues de spécimens d'herbiers, d'inventaires forestiers et de relevés de terrain, nous avons étudié Ies niches climatiques de quatre espèces d'arbres appartenant au genre Entandrophragma. Ces espèces fournissent un bois d'oeuvre de valeur ,et sont fortement exploitées dans divers pays d'Afrique centrale et occidentale, Des différences dans la répartition et l'abondance des espèces ont été mentionnées dans plusieurs pays:E. angolense etE cylindricum, qui sont souvent plus abondants localement qu'E candollei et E utile, sont respectivement plus abondants dans les forêts humides sempervirentes et semi-décidues. Les préférences en sols et éclairement de ces espèces ont été étudiées, surtout au stade plantule, mais aucune analyse globale n'avait été menée jusqu'à présent concernant les niches climatiques sur toute leur aire de répartition. Grâce à la modélisation à l'aide de SIG et des analyses statistiques, nous présentons ici la variation entre les niches climatiques de ces quatre espèces sur l'ensemble de leur aire de répartition. Toutes les espèces semblent éviter les climats les plus humides et s'expriment le mieux sous des conditions d'humidité intermédiaires, Ce travail procure un premier regard sur les préférences climatiques d'espèces arborescentes exploitées pour leur bois d'oeuvre en Afrique, Il fournit certaines bases pour la modélisation des aires de répartition selon différents scénarios de changement climatiques, pouvant servir à planifier la gestion de la biodiversité. (Texte intégral)

MorphologicaL variation was studied in 124 accessions from eight subgenera and 60 species among the most common cultivated and wild species of genus Passiflora with 127 descriptors. Twenty-four quantitative traits showing high variation among subgenera were selected. The three principal components of variation are associated with (i) flower length; (ii) flower width and bract shape; and (iii) peduncle branching, stem width and leaf length. The projection of accessions in the resultîng three-dimensional space consistently separates subgenera. A similar selection of 32 qualitative traits, and four categorized quantitative traits, allowed classifying our sample consistently. Our results support seven of the eight Killip's subgenera, but not Feuillet & MacDougal new infrasubgeneric classification. They converge however on many points with previous phylogenetîc results obtained with DNA sequences.

The list of Colombian Passifloraceae was revised, using 3.930 records from literature, herbaria, and field observations. It includes 167 species, 165 of them native, which is equivalent to 27% of the family. Our list includes more details on species distribution and presents 26 species new to Colombia. Passiflora is the most important genus, with 162 species, whose center of diversity is in the Ecuadorian and Colombian Andes. Inside Colombia, the highest diversity is concentrated in the Andean region, which houses 81% of the species, particularly in the departments of Antioquia, Valle del Cauca, Cundinamarca, Quindío, Risaralda, and Caldas. The highest number of species is found at between 1000 and 2000 m above sea level and the most common thrive in disturbed habitats, such as roadsides, cultivated plots, and secondary forests. Most of the 58 endemic species are found at between 1500 to 2500 in and belong mainly to subgenera Tacsonia and Decaloba. Forty-two species produce an edible fruit, and nine are commercially cultivated. Among the species reported, 70% are threatened to some degree and three are considered extinct. Colombia may still house many unknown species in poorly explored departments, but more information about Passiflora diversity and distribution is needed to develop its economic potential. The conservation of this threatened species along with its habitat is essential and urgent. Because of the species' multiple ecological interactions with many organisms, both aspects can be combined using Passifloraceae as an indicator of biodiversity in the Andean region.

Suivant les priorités établies par les réseaux éco-régionaux constitués des institutions régionales et nationales, la co-opération sur les fruitiers néotropicaux a été axée sur les passiflores et papayes, apportant des connaissances essentielles sur les relations entre espèces, leur diversité morphologique, cytogénétique, biochimique et moléculaire, leur distribution géographique et leurs adaptations éco-climatiques, ainsi que pour le développement de techniques de conservation des semences à faible coût. De nouvelles sources de résistances génétiques, y compris de nouvelles espèces, ont été identifiées. Ces connaissances sont directement utilisables pour la collecte et la conservation des ressources génétiques, in situ ou ex situ, et l'amélioration de ces espèces. Elles ont même été appliquées au contrôle d'une espèce envahissante dans des îles du Pacifique et en Nouvelle-Zélande.

Two genetic maps of DNA-markers (RAPD, AFLP and ISSR) of Ananas comosus var. bracteatus and A. comosus var. comosus have been previously published by our team. These maps were constructed at the Laboratory of Genetics and Plant Breeding of FERN, University of Algarve, using an F1 mapping population derived from a cross performed in Martinique between the two botanical varieties. However, the use of a F1 population, the small size of this population and the use of molecular markers with dominant inheritance allowed only markers that were heterozygous in the parents to be included in those maps and prevented the construction of an integrated high-density map. A new genetic map, intended to cover all the pineapple genome, is currently under construction using a mapping population of 142 F2 plants. This new map will integrate the already published maps and will include markers that had remained unlinked, as they were polymorphic but homozygous in parental geno-types, as well as newly identified markers. At the present time, the new map consists of seven linkage groups (> 40 cM) that integrate markers from both parents, 21 groups (> 40 cM) with markers mostly from one parent, six groups (< 40 cM and > 25 cM) with markers from one parent, and 12 smaller (< 25 cM) linkage groups, covering approximately 62% of the pineapple genome.

Babaco is the most important fruit crop among Ecuadorian mountain papayas. It belongs to Vasconcellea x heilbornii, which also includes plants with smaller fruit and interesting commercial perspectives, the baby-babacos. It is supposedly a hybrid between two occasionally cultivated species, V. stipulata and V. cundinamarcensis. Forty-three accessions of the three species were gathered in the collection of the University of Ambato, and characterized morphologically, using a list of 30 qualitative and 28 quantitative descriptors. The resulting data were submitted to factorial analyses and cluster analysis. Two types of babybabacos were identified on the basis of stipule and floral traits. One of them appeared closer to V. cundinamarcensis, suggesting varying degrees of introgression between the presumed parental species. Babacos and both types of babybabacos were separated in two or more distinct groups, showing a variation unexpected for vegetatively propagated crops. This differentiation shows an important geographic component. Once simply considered a sterile interspecific hybrid, the babaco appears submitted to a dynamic evolution and diversification process, which should be taken into account for creative hybrid breeding.

The relationship between papaya (Carica papaya) and its closest relatives, the mountain papayas (Yasconcellea spp.), was studied by PCR-RFLP analysis of three non-coding cpDNA regions (trnK3-trnK4, trnC9-trnD10. and trnD11-trnT12). The sample included eight accessions of C papaya and 54 accessions from 12 species of Vasconcellea. A high polymorphism was observed, even at the intraspecific level, with 42 different haplotypes. The neighbor joining cluster analysis and the principal coordinate analysis showed important distances between the two genera as well as within Vasconcellea. The Vasconcellea species most represented in the sample, V. cundinamarcensis, displayed a particularly wide variation. In this and other Vasconcellea species, a few accessions clustered with distinct species, suggesting chloroplast haplotype capture and a reticulate evolution in the genus. Two of the eight accessions of V. stipulate appeared closely related to V. x heilbornii, while the six others appeared more distant than such species as V. weberbaueri and V. parviflora, indicating that V. x heilbornii may have derived from a particular lineage of V. stipulata. Within V. x heilbornii (babaco and baby-babacos), variation was comparable to that of other species, which does not support a recent hybrid origin of these cultigens.

Genetic relations between the main cultivated passion fruits, as well as ,two of their wild relatives, were studied with AFLP markers. The 28-accession sample included six species from subgenus Passiflora (P. edulis, P. alata, P. quadrangularis, P. ligularis, P. tiliifolia, P. maliformis) and five from subgenus Tacsonia (P. tripartita, P. tarminiana, P. cumbalensis, P. mixta, P. antioquiensis). Three pairs of primers were selected on the basis of number and quality of polymorphic fragments. A total of 314 informative fragments were identified in the 80-500 bp range, 58% of them showing polymorphism. The neighbor joining cluster analysis grouped the accessions by species, and botanical varieties (P. tripartita) or forms (P. edulis). P. edulis displayed considerable variation, with a clear separation between its purple and yellow forms. The separation between the two subgenera was poor. At the intermediate series level, P. alata and P. quadrangularis were logically associated in a Quadrangulares branch, as well as P. ligularis and P. tiliifoliae in a Tiliifoliae branch. However, P. maliformis appeared independent from the latter. AFLP markers confirmed their interesting potential to study genetic diversity at the intraspecific level and among closely related species.

Microsatellite-containing sequences were isolated from an enriched genomic library of Carica papaya L. A total of 507 clones were evaluated with radioactive probes containing the motifs (GA)15 and (GT)15 and 147 positive clones were isolated and sequenced. The OLIGO 4.06 software was used to define 76 primer pairs. These primers were evaluated on three genotypes of C papaya and seven species of the genus Vasconcellea. Overall, 69 primer pairs worked in C papaya and 33 in Vasconcellea. The 35 pairs producing the best banding profiles were characterized on a sample of 29 individuals of C. papaya from the Caribbean region and 11 individuals of Vasconcellea from the Andes of Colombia and Ecuador. Twenty-six primer pairs gave polymorphism, of which 24 within C. papaya and only four within the seven Vasconcellea species, confirming the divergence between both genera. The number of alleles was 99, with a mean of 4 and an expected heterozygosity (He) of 0.56 per locus in C papaya. and 18, i.e. 4.5 per locus, in Vasconcellea, in the homozygous state. Microsatellite markers revealed more polymorphism in papaya than AFLP or RAPD.

The Colombian coffee-growing zone is one of the eco-climatic areas undergoing major impact of human activities in Colombia. It roughly corresponds to the 1000- 2000 m altitudinal range along the Cordilleras, where agriculture is principally based on growing of coffee, plantain and fruits (mainly citrics), and raising cattle. Large and middle-sized towns have grown steadily in the last decades, imposing new pressures on rural lands (e.g. river basin management for water supply, recreational activities), with negative but also potentially positive effects, such as the new conservation demand and the concomitant development of agro-ecotourism. With the general objective of providing scientific bases for environmental managers at the local and national levels, a study of the distribution of biodiversity was undertaken using as indicators two genera that show particular richness at medium to high altitudes: Passiflora (passion fruits) and Vasconcellea (mountain papayas). Geographical records were gathered for 3780 samples from herbaria, genebanks or the field, for 154 Passiflora and 10 Vasconcellea species. The DIVA-GIS and FloraMap software packages were used to produce maps of observed diversity and potential range of each species. Both genera show an altitudinal variation of their diversity, with a peak at intermediate elevations. Potential diversity is highest along the Cordillera Central, in the central coffee zone, and between the Cauca and Huila departments. Other hotspots appear in Antioquia, Tolima, Nariño, and the center of Cauca and Cundinamarca departments. With the exceptions of the central coffee zone, these hotspots have been poorly explored by botanists. The overlap between Passiflora and Vasconcellea hotspots underlines the consistency of these first results and constitutes a first validation of our choice of these two important taxa. (Texte intégral)

Después de una revisión histórica del cultivo comercial de pasifloras, se han inventariado 81 especies del género Passiflora con fruto comestible con base en experiencia de campo y en la literatura. Este número es muy superior a las estimaciones anteriores de 50 à 60 especies. Estas especies se concentran en los subgéneros Passiflora (43), Tacsonia y Manicata (17), Distephana (5), Decaloba (13), mientras que los subgéneros Dysosmia, Dysosmioides y Tacsonioides cuentan con una. Dentro del subgénero Passiflora, las series más promisorias son Incarnatae (5), incluyendo las dos formas de P. edulis y P. incarnata; Tiliifoliae (9), organizadas alrededor de las granadillas, con seis especies similares a P. ligularis, y de la gulupa, P. maliformis; Quadrangulares, con el maracuyá dulce (P. alata) y la badea (P. quadrangularis) formando un solo acervo genético; Laurifoliae, con 14 especies frutales superiores y muy similares, para evaluar; Lobatae, con 6 especies que podrían aportar genes de resistencia para las principales especies económicas, servirles de patrón, o desarrollarse como especies de doble uso (frutal y ornamental). El subgénero Tacsonia ofrece buenas posibilidades para mejorar y diversificar las curubas comercializadas: un grupo de 8 especies y variedades botánicas se puede explotar en el mejoramiento de las curubas actualmente cultivadas; además se podría rescatar el cultivo de la curuba roja y de la curuba antioqueña, basando su mejoramiento en amplios recursos genéticos (respectivamente 5 y 3 especies), así como el de la granadilla de montaña (P. pinnatistipula), operando una selección para mejorar el rendimiento de pulpa. Las 5 especies inventariadas para el subgénero Distephana podrían valorizarse como plantas de doble uso, ornamental y frutal. Las 13 especies del subgénero Decaloba y las 5 especies inventariadas en las series Serratifoliae, Simplicifoliae y Setaceae del subgénero Passiflora no presentan mayor interés como frutales comerciales.

Isozyme variation was studied in 87 plants from 32 cultivated and wild accessions of banana passion fruit (#P. tripartita# var. #mollissima#, #P. tripartita# var. #tripartita#, #P. tarminiana#, and #P. mixta#), rosy passion fruit (#P. cumbalensis#), tin-tin (#P. pinnatistipula#), gulián (#P. ampullacea#), #P. antioquensis#, #P. bracteosa#, and #P. manicata#, from the Andes of Venezuela, Colombia, and Ecuador. Six polymorphic enzyme systems (IDH, PGDH, PGM, DIA, PRX, and ACP) revealed 31 zymotypes characterized by the presence or absence of 31 electromorphs. Cluster analysis separated clearly the accessions of #P. tarminiana#, #P. tripartita#, #P. mixta#, and #P. cumbalensis# from the less typical species of subgenus #Tacsonia#, which is consistent with morphological evidence. #P. mixta# showed the highest intraspecific variation and the closest affinity with #P. tripartita#. The accessions of these two species formed two clusters, one dominated by Colombian genotypes and the other dominated by Ecuadorian genotypes. One of the #P. tripartita# var. #mollissima# accessions clustered close to #P. tarminiana# accessions. The affinity between these three species is particularly interesting for conservation and use of banana passion fruit genetic resources. All the other species formed monospecific clusters.

Geographic location data for 383 accessions of five Passiflora species from five Andean countries (P. cumbalensis, P. mixta, P. tripartita var. mollissima, P. natistipula, and P. manicata) were linked to interpolated continental surfaces of monthly mean rainfall, monthly mean temperature, and monthly mean diurnal temperature range. This permitted us to identify the potential distribution of each species and document its climatic adaptation. Maps are presented showing regions where the climate is similar to that in areas where each species has been found, but from which no collections have yet been made, thus representing possible geographical gaps in collections. Some species showed evidence of intra-specific variation in their climatic adaptation. The study of Passiflora diversity in Andean countries continues and these maps based on passport data are expected to be useful tools for the planning of both ex situ and in situ conservation activities.

On the basis of literature and field information on the utilization of passion fruits, 81 species giving an edible fruit were inventoried in the genus Passiflora. This figure is much higher than previous estimates of 50 to 60 species. Those 81 species are mostly concentrated in subgenera Passiflora (43), Tacsonia and Manicata (17), Decaloba (13), and Distephana (5), while subgenera Dysosmia, Dysosmioides and Tacsonioides include one species each. Within subgenus Passiflora, the most promising series are Incarnatae (5), including the two forms of P. edulis and P. incarnata; Tiliifoliae, with nine species organized around sweet granadillas, six of them very similar to P. ligularis, or the hard-shelled granadilla (P. maliformis); Quadrangulares (3), with sweet maracuja (P. alata) and the giant granadilla (P. quadrangularis) that form a same gene pool possibly including P. trialata; Laurifoliae, with 14 superior and very similar fruit species, needing evaluation; Lobatae, with six species that can contribute resistance genes to the main economic species, be used as rootstock, or be developed into double purpose species (fruit and ornamental) for the garden. Subgenus Tacsonia offers good perspectives to improve and diversify the currently commercialized banana passion fruits, using germplasm from eight closely related species and botanical varieties. In addition, the cultivation of the rosy passion fruit and the Antioquia banana passion fruit could be maintained and improved, enriching the genetic basis of these crops with five and three closely related species respectively. Cultivation of the mountain granadilla (P. pinnatistipula) could benefit from breeding for smaller seeds and higher pulp content. At least five red-flowered fruit species mentioned for subgenus Distephana could be bred into double purpose plants for the tropical garden. The 13 species from subgenus Decaloba and 5 species from series Serratifoliae, Simplicifoliae e Setaceae of subgenus Passiflora present no interest for the development of commercial fruit crops.

Vasconcellea cundinamarconsis is one the best known and most promising mountain papayas. Reported here are spindle absence and the resulting abnormalitles, as chromosome missegregation, micronucler-dependent cylokinesis and cell death in one accession collected in the Andes of Ecuador. Spindle absence and cell death resulted in a high trequency of unviable meiotic products (83.48%). We propose the hypothesis of a detective spindle checkpoint leading to the absence of spindle microtubules in this accession of V. cundinamarcensis. However, this faulty checkpoint did not impede the progress and completion of meiosis, although in a non-conventional manner.

DNA variation was studied at the intra- and interspecific levels within the genus #Passiflora#, with particular emphasis on the subgenus #Tacsonia# and its relationship with the subgenus #Passiflora#. AFLP fingerprints were generated for 35 accessions from 21 species, 14 of which belong to subgenus #Tacsonia#, and four to subgenus #Passiflora#. The morphologically intermediate #P. manicata# (subgenus #Manicata#) was also included, as were #P. trinervia# (subgenus #Psylanthus#) and #P. alnifolia# (subgenus #Decaloba#). The two latter were used as outgroup species. Two primer combinations generated 34-80 scorable fragments per genotype for a total of 260 fragments. Polymorphism analyses spanned the levels from individual genotype to section. Subgenus #Tacsonia# presented wide genetic variability at both intra- and interspecific levels, particularly within wild species. The classification based on these markers generally agrees well with current taxonomic definitions of common species, but less with definitions of sections. A geographical component was evident in the intraspecific variation of #P. mixta#, #P. tripartita# var. #mollissima# and #P. tarminiana#, with wider variation in Ecuador and Peru than in Colombia and Venezuela. These same three species. plus #P. cumbalensis#, formed adjacent clusters, showing closer affinity with each other than with the other species of subgenus #Tacsonia#. As expected, #P. manicata# clustered at an intermediate position between subgenera #Tacsonia# and #Passiflora#.