Student Number : 0413249D -
MSc research report -
Faculty of Science / Cassava is one of the most important staple crops in the world and is
consumed by over 700 million people around the globe and is a profitable product
commercially due to the high starch content of its tubers. One of the future aims is to
produce cassava that is high yielding, resistant to cassava mosaic geminiviruses
(CMGs) and high in starch content. To be able to achieve commercially attractive
cassava varieties, research need to be carried out to investigate the virus resistance
status of different cassava cultivars, which can later be used in the future breeding
programme.
In South Africa, cassava is used for commercial starch manufacturing
purposes, as a cash crop and a food source by small-scale farmers. Cassava Mosaic
Disease (CMD) is having a negative impact on yield of the crop globally and
therefore dropping profitability of cassava on a commercial scale.
The aims of this research were to propagate thirteen cassava cultivars and then
to test them for virus susceptibility or resistance.
Eleven cassava cultivars received from the International Institute of Tropical
Agriculture (IITA) were tested for resistance or susceptibility against South African
cassava mosaic virus (SACMV). Two local, commercial cultivars T200 and T400,
were tested for East African cassava mosaic virus (EACMV) and African cassava
mosaic virus (ACMV) resistance.
Cassava cultivars were successfully propagated in vitro and thereafter
transferred into soil and acclimatized to adapt to environmental conditions. When the
plantlets were three weeks old, the plantlets were infected with cassava mosaic
viruses. Plants were infected with SACMV via Agrobacterium-mediated transfer and
infectious EACMV and ACMV monomers were used to biolistically bombard the
plantlets.
Resistance/susceptibility results of seven of the thirteen cultivars were
obtained with SACMV, these cultivars being T200 (susceptible), T400 (susceptible), TME3 (highly resistant), I30572 (susceptible), I420251 (highly susceptible), I60506
(susceptible) and TMS60444 (susceptible). Due to destruction by fungal gnats eating
the roots of the plants, acclimatization of the remaining six cultivars was not possible.
Also, due to the nature of the biolistic equipment, infection of the cultivars with
EACMV and ACMV was not achieved as the plantlets were not robust enough to
survive the pressure.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/1558 |
| Date | 01 November 2006 |
| Creators | Osman, Rozida Haroon |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | 488392 bytes, 54710 bytes, application/pdf, application/pdf, application/pdf, application/pdf |
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