Progress 09/01/04 to 08/31/07
Outputs
OUTPUTS: Micropropagation of cassava is relatively straightforward and shoots from microcuttings can root without plant growth regulators in vitro. However, acclimatizing in vitro rooted shoots can result in high mortality. Cassava roots are prone to deterioration following wounding or bruising causing great losses during acclimatization. Direct rooting was conducted of cassava shoots pretreated by growing them in vitro on 0% to 10% sucrose. Shoots, 1.5 cm in length from the varying sucrose media were rooted in vitro in medium grade vermiculite or in situ in peat-based potting medium. PARTICIPANTS: University of the Virgin Islands Agricultural Experiment Station Biotechnology Program conducted the research in the Biotechnology lab. TARGET AUDIENCES: The target audiences are the local crop farmers and backyard growers. These producers normally have less than two acres under production. The Virgin Islands has only three producers with total production acreage over two acres. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The varying levels of sucrose in the tissue culture media did have an influence on plant growth and development. The shoot length increased with the increasing concentration of sucrose from 0% to 4%. Levels of sucrose from 6% to 10% had reduced shoot growth that could be attributed to the increased osmotic potential of the media. The thickness of the stem also was observed to increase as the sucrose level increased resulting in more compact plants. Cassava grown on 0% to 1% sucrose were more spindly having smaller and thinner leaves. Roots were first observed on the fifth day after transfer into MS media for all sucrose concentrations. The greatest number of roots after 28 days was on the 6% sucrose medium.
Publications
- No publications reported this period
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Progress 01/01/06 to 12/31/06
Outputs
Cassava is being grown in vitro under multiple carbohydrate concentrations to assess the accumulation of starch in the root and stem tissues. As the sucrose concentration of the tissue culture medium increases, so does the osmotic potential of the medium. Exposing in vitro grown plants to a higher osmotic potential is expected to assist in the acclimatization of the plants when they are removed from the tissue culture environment and established ex vitro.
Impacts
The reduced loss of plants during acclimatizing from a higher sucrose medium saves the grower time and effort.
Publications
- No publications reported this period
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Progress 01/01/05 to 12/31/05
Outputs
Micropropagation of cassava is relatively straight forward and shoots from microcuttings can root without plant growth regulators in vitro. However, acclimatizing in vitro rooted shoots can result in high mortality. Cassava roots are prone to deterioration following wounding or bruising causing great losses during acclimatization. Direct rooting was conducted of cassava shoots pretreated by growing them in vitro on 0% to 10% sucrose. Shoots, 1.5 cm in length from the varying sucrose media were rooted in vitro in medium grade vermiculite or in situ in ProMix potting medium. Sucrose levels >6% caused shorter plants than the other treatments. Shoots rooted equally well with both media. A success rate of >95% was obtained following rooting in vermiculite followed by transfer and acclimatization in a ProMix potting medium. Vermiculite was easily removed from cassava roots reducing the damage normally occurring during the rinsing and removal of adhering gelled medium. In
vitro rooting of cassava in vermiculite increases survival rates during acclimatization. Direct rooting in pots was most successful from shoots grown on 4% to 8% sucrose.
Impacts
New cassava can be efficiently made available to farmers from tissue culture and used within a short amount of time.
Publications
- Zimmerman, T.W., K. Williams, L. Joseph, J. Wiltshire and J.A. Kowalski. 2006. Rooting and Acclimatization of Cassava (Manihot esculenta) Ex Vitro. Acta Hort. (in press).
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Progress 01/01/04 to 12/30/04
Outputs
Cassava micropropagation was initiated with the investigation of sucrose concentration on in vitro cassava growth. Sucrose concentrations ranged from 0-10 percent. The higher sugar concentrations reduced the growth rate and elongation.
Impacts
Stronger more marketable in vitro grown plants has cut the expense to micropropagators.
Publications
- Zimmerman, T.W. 2004. Preliminary studies on the influence of carbohydrate concentration on cassava growth in vitro. Proc. 40th Caribbean Food Crops Society. 40: (in press).
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