ant, J, V, 1996, Embryogenic cell suspensions from tiie male flower of Musa AAA cv. Grand nain. -Physiol, Plant, 97; 285-290, There are very few reports on the establishment of iong-term embrj'ogenic cell cuitures of banana, especially of triploid cultivars of commercial interest, Embryogenic cell suspensions were prepared using the cuitivar Grand nain, the most widely grown dessert banana in the world. After culture for 5 or 6 months of immattire male flowerbuds adjacent to the floral apex, yeilow, compact calluses and white, friable embrj'Ogenic tissues were induced. Suspension cultures were initiated ffom embryogenic tissues placed in liquid medium. The packed cell volume (PCV) of the suspensions increased 2-to 5-fold with each monthly culture cycle. Plating of tiie embryogenic suspensions resulted in approximately 370X10' embrj'os per ml of PCV, Depending on the size of embryos, 3 to 20% germination was observed, A histological survey of cell suspensions and embryo development was carried out. Cellular aggregates with cells displaying typical embryogenic features were formed. Most of the somatic embiyos were probably of unicellular origin. ), R. Domergue, S. Monmarson, J. Schwendiman and C Teisson. CIRAD-FLHOR. Laboratoire BIOTROP. B.P. 5035. Av. du val de Montferrand,

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Suspensions of embryogenic cells of a triploid banana (Musa spp., cv. Bluggoe) were initiated from the uppermost part of meristematic buds, and used as protoplast source. After 20 weeks in culture, the suspension contained a mixture of globular structures or globules and embryogenic cell clusters, as well as single cells. Two types of protoplasts were obtained from embryogenic suspension culture: small (20-30 μm) and larger (30-50 μm) protoplasts with a dense cytoplasm and large starch grains respectively. The small protoplasts probably originated from embryogenic cell clusters, and also from pseudocambial cells of globules, while larger protoplasts were probably released from oval starchy cells and those of the globule peripheral area. In co-culture with a suitable feeder, consisting of suspensions of diploid banana cells, the protoplasts of triploid banana reformed the cell wall within 24 h and underwent sustained divisions leading to the formation of small clusters of 2-3 cells within 7 days. The latter developed directly into embryos without passing through an apparent callus phase. 10% of such embryos gave rise to plantlets when subcultured in 2.2 μM 6-benzylaminopurine and 2 μM 4 amino-3,5,6-trichloropicolinic acid for 1 week, before transfer to MS medium containing 10 μM 6-benzylaminopurine. The rest of the embryos underwent intensive direct secondary embryogenesis which could lead to the formation of plantlets with a frequency of up to 50% upon further transfer to hormone-free medium.

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F 34032 Montpellier Cedex RÉSUMÉ L'examen de l'état des sacs embryonnaires dans des échantillons de jeunes fruits de palmier à huile a conduit à l'élaboration d'un modèle probabiliste de la fertilité dans le genre Elaeis. Celle-ci dépend de deux paramètres : P I , probabilité pour un ovule de former un sac embryonnaire normal, et P 2 , probabilité de sa fécondation. Un troisième paramètre R, dit de compétition, tient compte des avortements de sacs embryonnaires normaux survenant en raison de la présence d'un ovule déjà fécondé dans une fleur. Les prévisions de ce modèle sont en accord avec les observations effectuées chez l'hybride F I Elaeis melanococca x Elaeis guineensis comme chez les espèces parentales. SUMMARY Principles of analysis of female fertility in F, oil-palm hybrids Elaeis melanococca x Elaeis guineensis and in the parental species. Probabilistic model and biological interpretation. An examination of the state of embryo sacs in samples of young fruits of oil-palm allowed the development of a probabilistic model of fertility in the genus Elaeis. Fertility was found to depend on two parameters : P!, probability for an ovule to give a normal embryo sac, and P 2 its probability to be fertilized. A third parameter R, namely competition, took into account abortions of normal embryo sacs occurring because another ovule has already been fertilized in the flower. The predictions of this model were in agreement with the observations made in the F, hybrid Elaeis melanococca x E. guineensis, as in the parental species.