Impact of osmotic dehydration on the encapsulated apices survival of two yams (<i>Dioscorea</i> spp.) genotypes from Benin

Abstract

Objective: Cryopreservation is one of the biotechnological methods currently used for long term conservation of plant genetic resources. It requires many steps such as a pretreatment, which involves cells dehydration in order to make them tolerant to desiccation and freezing in nitrogen liquid using high sucrose concentration. The present study aims to establish a protocol for long term conservation of yam germplasm in Benin using encapsulation/dehydration technique. Methodology and Results: The effects of different sucrose concentrations and immersion durations on encapsulated apices of two yams genotypes (Da93G1 from Dioscorea alata and Dcr164 from complex Dioscorea cayenensis/ D. rotundata) were tested. The apices were excised from six months old vitroplants on stereoscope and transferred in M1 medium (MS+2g.L-1 activated charcoal) prior to encapsulation in alginate (3%) beads with calcium chloride (1.32M). Then, the apices were exposed to osmotic dehydration with two concentrations of sucrose (0.75M and 1.25M) at two durations (24h and 40h) before their culture in M2 medium (MS + 2mg.L-1 BAP, 100µg.L-1 d'ANA and 2g.L-1 activated charcoal). Conclusion and application: The results showed that 0.75M sucrose increased high survival rate (80%) and high rate of regenerated plant (70%) at 24h of immersion duration. Furthermore, significant difference was observed between the two genotypes response. This work has allowed adopting in further experiments 0.75M sucrose and 24hours of immersion duration in pretreatment of yam apices for the development of cryopreservation techniques for yam conservation in Benin.

Effect of Various Preculture and Osmotic Dehydration Conditions on Cryopreservation Efficiency and Morphogenetic Response of Chrysanthemum Shoot Tips

“…However, in Dioscorea spp. shoot apices, a higher survival and regeneration rates were reported after applying 24-h dehydration, as compared to longer (40-h) treatment [Agbidinoukoun et al 2013]. In the present study a short (4-day) osmotic dehydration proved more optimal in terms of explants survival, their regrowth potential and the quality of the microshoots produced than that 7-day-long one, which is in conjunction with a poor response of the explants to higher sucrose concentrations during preculture.…”

Morphogenetic response of shoot tips to cryopreservation by encapsulation-dehydration in a solid mutant and periclinal chimeras of Chrysanthemum × grandiflorum /Ramat./Kitam.

“…As for Gladiolus, shoots from two in vitro-grown cultivars were sensitive to KIN resulting in a high rate (20-80%) of abnormal-looking regenerants (Joung et al 2007). According to Agbidinoukoun et al (2013), the callus induction mechanism is still poorly understood and depends mostly on genotype, which could explain the differences between cultivars observed in this study.…”

Assessment for the Incidence of Number of Subcultures on Genotype Stability for In Vitro Plantlets of Yam (Dioscorea spp.) Using RAPD Markers

“…Despite in-situ conservation is preferentially applied for genetic resources for several woody species and cultivated species, ex-situ conservation remain the challenge for maintenance of the non-orthodox and vegetative propagated species (Engelmann, 2010). Since, several studies reported that cells and organs in vitro culture techniques are successfully used for conservation of yam germplasm (Engelmann, 1991;Ahanhanzo et al, 2003;Mandal and Sonali, 2007;Agbidinoukoun et al, 2013). Those techniques offer more advantages such as rapid multiplication of explants, require lower area, free diseases plantlets production.…”