Résumé. Un nouveau procédé de cryoconservation comprenant une étape de dessiccation au silicagel ... more Résumé. Un nouveau procédé de cryoconservation comprenant une étape de dessiccation au silicagel avant la congélation dans l’azote liquide a été développé pour les embryons somatiques standards de palmierà huile. II a été appliqué avec succès en France et en Côted‘Ivoire à 39 clones différents. La survie après cryoconservation a éré obtenue avec tous les clones, avec des taux variant entre 2 et 100%. Les clones ayant un aspect morphologique normal ont présenié un taux de survie significativement plus élevé (31% en moyenne) que ceux en mauvais état physiologique (12% en moyenne). La cryoconservation est maintenant appliquée en routine aux embryons somatiques de palmier àhuile avec ce procédé amélioré.
Cost information is useful to monitor the performance of the genebanks. Thus, managers, users, an... more Cost information is useful to monitor the performance of the genebanks. Thus, managers, users, and donors of the genebanks can have an idea of the relative costs of managing plant genetic resources. This information can be used to make users but especially donors aware of the actual costs of conserving and distributing accessions and in this way facilitate fund raising. Managers however do have an idea of genebank operational costs. What is then the added value of using a periodic system to collect costs information for the genebank manager? In this section we present some specific cases where the information collected in the genebanks visited can help in the decision process. It is true that the current amount of information does not allow us to make conclusions across centers, but it does allow for some analysis within the centers.....
African yam bean (Sphenostylis stenocarpa Hochst ex. A. Rich.) Harms is an underutilized tropical... more African yam bean (Sphenostylis stenocarpa Hochst ex. A. Rich.) Harms is an underutilized tropical African tuberous legume. It belongs to the class Magnoliopsida; order Fabales; family Fabaceae; subfamily Papilionoideaea; and genus Sphenostylis. There are seven species in the genus Sphenostylis (Potter and Doyle 1994). African yam bean (AYB) is the
BACKGROUND: A cryopreservation protocol has been established for oil palm somatic embryos (SEs)... more BACKGROUND: A cryopreservation protocol has been established for oil palm somatic embryos (SEs), the efficiency of which must be evaluated, both in terms of regeneration and of long-term storage capacity, before its large-scale routine use. OBJECTIVE To test the survival and recovery of 29 clones of oil palm somatic embryos cryostored for 20 years. MATERIALS AND METHODS Clumps of SEs were pregrown for 7 days on medium containing 0.75 M sucrose, dehydrated in air-tight containers containing silica gel to moisture contents between 19-35% fresh weight, and then immersed directly in liquid nitrogen and stored in cryotanks for 20 years. RESULTS Survival of SEs cryopreserved and rewarmed immediately displayed an average value of 19.1% for the 29 clones tested while survival of SEs rewarmed after 20 years of cryostorage was significantly higher, with an average of 33.2% for the 28 surviving clones. Out of these 28 surviving clones, three were lost due to contamination or regrowth decline...
Some genetic studies using molecular methods such as diversity assessment or marker-assisted sele... more Some genetic studies using molecular methods such as diversity assessment or marker-assisted selection require collection of a large number of samples from fields located in the vicinity or in remote areas, followed by isolation of good quality DNA in a short time span. In the present study, different tissue preservation methods were compared for subsequent DNA extraction using a modified CTAB method in two 96-well plates, following grinding of leaf tissues with a GenoGrinder 2000. We found that preservation of leaf tissues in NaCl-CTAB-azide buffer (as described in Rogstad, 1992) at 4°C is a better storage procedure than preservation at -20°C to obtain good quality DNA. Comparison of DNA extraction with or without use of phenol revealed that the quality of DNA was not drastically affected when non-phenol extraction protocol was used and did not affect PCR amplification. Thus, the recommended DNA extraction procedure allowed us to process 192 samples per day at a cost of $0.80 per s...
DSC analysis was performed at three points in the cryopreservation process on encapsulated-dehydr... more DSC analysis was performed at three points in the cryopreservation process on encapsulated-dehydrated meristems of Ribes ciliatum. Meristems were excised from shoots pre-treated with either sucrose or glucose, encapsulated in alginate beads, dehydrated in sucrose solutions, air dried, and plunged in liquid nitrogen. Thermal analysis revealed glass transitions during cooling of air-desiccated meristems, however, on rewarming a small endothermic event was detected suggesting glass destabilization can occur. Interestingly, this did not occur in alginate beads or meristems when these components were cooled and rewarmed separately. The possibility exists that thermal and moisture gradients may arise within the alginate bead/tissue complex and we propose that the heterogeneous composition of the meristems and the surrounding alginate may promote ice nucleation on rewarming. The significance of this regarding the stabilization of glasses formed in alginate beads and their encapsulated meri...
Wild Crop Relatives: Genomic and Breeding Resources, 2011
ABSTRACT Dioscorea spp., belonging to Dioscoraceae family, are important staple food crop for ove... more ABSTRACT Dioscorea spp., belonging to Dioscoraceae family, are important staple food crop for over 300 million people in the tropics and subtropics. They are mostly grown for their starchy tubers (both cultivated and wild) and for medicinal properties. Cultivated yams are vegetatively propagated while wild yams are sexually propagated and comprise both diploid and polyploid species. Although yam is an economically and socially important crop, limited research has been conducted to understand the complexity of the domestication process traditionally followed mainly in West Africa to develop new cultivars. The genetics and genomics of this crop is least understood due to several biological constraints and lack of research efforts. Some progress, however, has been made recently to understand the phylogeny and phylogenetic relationships within the genus, Dioscorea, and cytogenetics of the wild and cultivated species. Genetic linkage maps have been constructed for one wild species, D. tokoro and two cultivated species, Dioscorea alata and D. rotundata, and QTLs for yam mosaic virus were identified in D. rotundata and anthracnose disease in D. alata. Advances were also made in genetic transformation, including in vitro plant regeneration, gene delivery, and recovery of transgenic plants but this method still needs improvements to generate genetically modified plants. This chapter discusses the available information on Dioscorea, irrespective of wild or cultivated status, as information available on wild species is very limited and is not separable from that of cultivated ones.
Résumé. Un nouveau procédé de cryoconservation comprenant une étape de dessiccation au silicagel ... more Résumé. Un nouveau procédé de cryoconservation comprenant une étape de dessiccation au silicagel avant la congélation dans l’azote liquide a été développé pour les embryons somatiques standards de palmierà huile. II a été appliqué avec succès en France et en Côted‘Ivoire à 39 clones différents. La survie après cryoconservation a éré obtenue avec tous les clones, avec des taux variant entre 2 et 100%. Les clones ayant un aspect morphologique normal ont présenié un taux de survie significativement plus élevé (31% en moyenne) que ceux en mauvais état physiologique (12% en moyenne). La cryoconservation est maintenant appliquée en routine aux embryons somatiques de palmier àhuile avec ce procédé amélioré.
Cost information is useful to monitor the performance of the genebanks. Thus, managers, users, an... more Cost information is useful to monitor the performance of the genebanks. Thus, managers, users, and donors of the genebanks can have an idea of the relative costs of managing plant genetic resources. This information can be used to make users but especially donors aware of the actual costs of conserving and distributing accessions and in this way facilitate fund raising. Managers however do have an idea of genebank operational costs. What is then the added value of using a periodic system to collect costs information for the genebank manager? In this section we present some specific cases where the information collected in the genebanks visited can help in the decision process. It is true that the current amount of information does not allow us to make conclusions across centers, but it does allow for some analysis within the centers.....
African yam bean (Sphenostylis stenocarpa Hochst ex. A. Rich.) Harms is an underutilized tropical... more African yam bean (Sphenostylis stenocarpa Hochst ex. A. Rich.) Harms is an underutilized tropical African tuberous legume. It belongs to the class Magnoliopsida; order Fabales; family Fabaceae; subfamily Papilionoideaea; and genus Sphenostylis. There are seven species in the genus Sphenostylis (Potter and Doyle 1994). African yam bean (AYB) is the
BACKGROUND: A cryopreservation protocol has been established for oil palm somatic embryos (SEs)... more BACKGROUND: A cryopreservation protocol has been established for oil palm somatic embryos (SEs), the efficiency of which must be evaluated, both in terms of regeneration and of long-term storage capacity, before its large-scale routine use. OBJECTIVE To test the survival and recovery of 29 clones of oil palm somatic embryos cryostored for 20 years. MATERIALS AND METHODS Clumps of SEs were pregrown for 7 days on medium containing 0.75 M sucrose, dehydrated in air-tight containers containing silica gel to moisture contents between 19-35% fresh weight, and then immersed directly in liquid nitrogen and stored in cryotanks for 20 years. RESULTS Survival of SEs cryopreserved and rewarmed immediately displayed an average value of 19.1% for the 29 clones tested while survival of SEs rewarmed after 20 years of cryostorage was significantly higher, with an average of 33.2% for the 28 surviving clones. Out of these 28 surviving clones, three were lost due to contamination or regrowth decline...
Some genetic studies using molecular methods such as diversity assessment or marker-assisted sele... more Some genetic studies using molecular methods such as diversity assessment or marker-assisted selection require collection of a large number of samples from fields located in the vicinity or in remote areas, followed by isolation of good quality DNA in a short time span. In the present study, different tissue preservation methods were compared for subsequent DNA extraction using a modified CTAB method in two 96-well plates, following grinding of leaf tissues with a GenoGrinder 2000. We found that preservation of leaf tissues in NaCl-CTAB-azide buffer (as described in Rogstad, 1992) at 4°C is a better storage procedure than preservation at -20°C to obtain good quality DNA. Comparison of DNA extraction with or without use of phenol revealed that the quality of DNA was not drastically affected when non-phenol extraction protocol was used and did not affect PCR amplification. Thus, the recommended DNA extraction procedure allowed us to process 192 samples per day at a cost of $0.80 per s...
DSC analysis was performed at three points in the cryopreservation process on encapsulated-dehydr... more DSC analysis was performed at three points in the cryopreservation process on encapsulated-dehydrated meristems of Ribes ciliatum. Meristems were excised from shoots pre-treated with either sucrose or glucose, encapsulated in alginate beads, dehydrated in sucrose solutions, air dried, and plunged in liquid nitrogen. Thermal analysis revealed glass transitions during cooling of air-desiccated meristems, however, on rewarming a small endothermic event was detected suggesting glass destabilization can occur. Interestingly, this did not occur in alginate beads or meristems when these components were cooled and rewarmed separately. The possibility exists that thermal and moisture gradients may arise within the alginate bead/tissue complex and we propose that the heterogeneous composition of the meristems and the surrounding alginate may promote ice nucleation on rewarming. The significance of this regarding the stabilization of glasses formed in alginate beads and their encapsulated meri...
Wild Crop Relatives: Genomic and Breeding Resources, 2011
ABSTRACT Dioscorea spp., belonging to Dioscoraceae family, are important staple food crop for ove... more ABSTRACT Dioscorea spp., belonging to Dioscoraceae family, are important staple food crop for over 300 million people in the tropics and subtropics. They are mostly grown for their starchy tubers (both cultivated and wild) and for medicinal properties. Cultivated yams are vegetatively propagated while wild yams are sexually propagated and comprise both diploid and polyploid species. Although yam is an economically and socially important crop, limited research has been conducted to understand the complexity of the domestication process traditionally followed mainly in West Africa to develop new cultivars. The genetics and genomics of this crop is least understood due to several biological constraints and lack of research efforts. Some progress, however, has been made recently to understand the phylogeny and phylogenetic relationships within the genus, Dioscorea, and cytogenetics of the wild and cultivated species. Genetic linkage maps have been constructed for one wild species, D. tokoro and two cultivated species, Dioscorea alata and D. rotundata, and QTLs for yam mosaic virus were identified in D. rotundata and anthracnose disease in D. alata. Advances were also made in genetic transformation, including in vitro plant regeneration, gene delivery, and recovery of transgenic plants but this method still needs improvements to generate genetically modified plants. This chapter discusses the available information on Dioscorea, irrespective of wild or cultivated status, as information available on wild species is very limited and is not separable from that of cultivated ones.
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