Taxonomic and Electrophoretic Studies of Selected Species of Ganoderma (Karst.)
Ganoderma, the causal pathogen of Basal Stem Rot, is found in association with all major plantation crops in Malaysia, but the most severe debilitation caused is when they are found on oil palms. It is not known how many species/pathogenic types there are, whether a differential degree of virule...
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| Format: | Thesis |
| Language: | English English |
| Published: |
1996
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/10384/1/FP_1996_15_A.pdf |
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| Summary: | Ganoderma, the causal pathogen of Basal Stem Rot, is found
in association with all major plantation crops in Malaysia, but the
most severe debilitation caused is when they are found on oil palms.
It is not known how many species/pathogenic types there are,
whether a differential degree of virulence existed, and whether the
fungus is host-specific. Ganoderma taxonomy is still controversial
and could not effectively aid pathological considerations. This study was carried out to fulfill 4 main objectives. The first was to
determine the diversity and percentage distribution of sporophore
types found in association with oil palms. The second was to
determine a means of inducing sporophore production under
controlled conditions, starting from mycelial cultures. The third
was to characterise the samples based on sporophore morphology,
mycelial types and vegetative compatibility of isolates within and
between groups. The fourth was to assess the relationship of
Ganoderma within and between sampling groups using the
Numerical Taxonomy Systematics computer programme based on
Roger's Distance Measure (DJ The raw data were obtained from
isozyme electrophoresis, using mycelial extracts. A morphological
assessment showed a total of seven colour types found on oil palms
and coconut stumps in West Malaysia. Four were recognised as G.
boninense, G. miniatocinctum, G. chalceum and G. tornatum,
but descriptions for three others (CT3, CT5 and CT7) could not
be found and were assumed yet to be taxonomically annotated.
Success with sp orophore induction techniques has aided
morphological characterisation procedures in this study and its
viability has introduced a potential basis for a further and more
intensive conventional systematics investigations. Mycelial
characterisation did not show any correlation with the variety of
sporophore colours. Isozyme electrophoresis did not reciprocate the polymorphism exhibited by Ganoderma sporophores, but
yielded important informations on distance relationships. Acid
Phosphatase and Malate Dehydrogenase were good marker
isozymes as they could distinguish successfully, isolates of palmhosts
from isolates of tree-hosts. No similar marker-isozyme existed
for isolates within the palm-hosts, although (with the exception of
EGP series for Cholinesterase) no isolate from oil palm showed
bands identical to the isolates from coconut stumps and vice versa.
The resultant dendrogram based on Roger's Distance (D) showed
three major clusters at 0.31, 0.48 and 0.66. The first major cluster
divides the population into isolates of palm-hosts vs. tree-hosts.
Results from numerical analysis showed that host type was a
stronger basis for a close relationship, and that geographical origin
and/or a common symptomology was less relevant. |
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