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CBN-V Video Archives - S7-09
Cryopreservation of Cassava Shoot Tips using the
Encapsulation-Dehydration Technique
Escobar R.H.1,
N.C. Manrique2, D.G. Debouck1, J. Tohme2,
and W.M. Roca2
1. Genetic Resources Unit Centro Internacional de Agricultura
Tropical (CIAT) Apartado Aéreo 6713, Cali, Colombia
R.ESCOBAR@CGIAR.ORG
2. Biotechnology Research Unit, CIAT, Apartado Aéreo 6713, Cali,
Colombia
The encapsulation-dehydration technique allows the direct placing of
cassava meristematic tissues into liquid nitrogen, avoiding the use
of expensive equipment and thereby offering the possibility of
large-scale, long-term conservation at low cost. Different
concentrations of sodium alginate, CaCl2, sucrose and growth
regulators, in pre- and post-freezing phases have been tested. Low
alginate and CaCl2 deformed beads, resulted in difficult handling
and drying. Cassava has shown to be sensitive to direct exposure to
high sucrose levels. Shoots grown on medium supplemented with
kinetin and treated with 0.75 M sucrose showed differential response
in terms of shoot recovery after freezing. Drying conditions (i.e.
time) were key to recover of viable shoots. Three hundred genotypes
of the core collection of 630 clones are currently being tested.
With data from 108 genotypes we have established three groups based
on shoot recovery after freezing: a high-recovery group of 32
genotypes with 70-97% recovery, an intermediate group of 52
genotypes with 30-70% recovery, and 24 genotypes with low-recovery,
below 30%. We found that by adjusting post-freezing media and
conditions, a 5-10% increases in recovery could be obtained. We are
testing reproducibility and duration in liquid nitrogen as steps to
determine logistical aspects in the management of an in vitro
based gene bank.
For further information, see spoken
presentation Escobar et al. S7-07
2007©
Donald Danforth Plant Science Center All rights reserved.
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