African Journals Online
JOURNAL OF THE GHANA SCIENCE ASSOCIATION
VOLUME
1 NUMBER 3, ABSTRACTS
On the teaching of mathematics at the Lower Secondary
School level
G. O. Lartey
Department of Mathematics, University of Science and Technology, Kumasi
ABSTRACT
Teaching of mathematics at the lower Secondary School level in Ghana has
been hindered primarily because of properly trained mathematics tutors for
the purpose. Yet it is very well known that scientific knowledge and
technological advancement if hinged on mathematics. In order to demonstrate
how effective the teaching and learning of mathematics can be at the lower
Secondary School level, an experimental mathematics class was initiated to
examine the effect of consistent teaching of mathematics during the early
years of a child’s secondary education. After about three years, the
results for these groups of Secondary School students preparing for their
G.C.E. ‘O’ level examination who participated at different points of time
during the programme were examined. It turned out that those who were taught
early and were motivated early in their learning at that level proved better.
It was also clear that the sex of the student did not affect his/her
performance.
Preliminary studies on extraction techniques and their
effects on the quality of tomato (Lycopersicon esculentum, Mill) seeds
Nana S. Olympio and J. O Dankyira
Department of Horticulture,
University of Science and technology, Kumasi.
ABSTRACT
An experiment was carried out to
observe the effect of different method of seed extraction on the quality of
the seed obtained from tomato (Lycopersicon esculentum, Mill) variety
“Power”. The extraction techniques used were:- hydrochloric acid,
sulphuric acid, lemon juice, and two fermentation periods, one or three days,
and no fermentation. The best treatments were the fermentation for one or
three days and lemon juice, with the resultant seed viability of over 90%.
Acid extraction techniques, though fast and efficient, were expensive,
difficult to use and gave 11.83 and 18% of abnormal seedlings and 17.75 and
50.25% dead seeds. The use of fermentation for 3 days also produced the least
percent 9% fungi infected seeds, closely followed by the use of lemon juice.
A higher percentage (50 and 47%) of fungi infected seeds were recorded in
seed treated with acids. The most common seed-borne fungi identified on the
fermentation extracted seed were Fusarium spp, Curvalaria
pallenscens and C. geniculata. For the acid extracted seed, Aspergillus
flavus and A terreus were the most common.
Influence of weather and
soil factors on the incidence and severity of damage by cassava green mite
and performance of a released phytoseiid in Gomoa district of the Central
Region of Ghana
Y. Opoku-Asiama1, E. A. Abole2
and J. S. Yaninek
1Department of
CropScience, University of Cape Coast
2Institute of
Education, University of Cape Coast
3International
Institute of Tropical Agriculture, Cotonou, Benin
ABSTRACT
The main objective of the study was to investigate how weather and soil
factors in Gomoa district of the Central Region of Ghana affected the
incidence and severity of damage of the cassava green mite (CGM) and also the
performance of a phytoseiid – a biocontrol agent against the green spider
mite. The study was carried out on 10 cassava farms along a major from Accra
to Cape Coast within the area where a phytoseiid, Typhlodromalus manihoti,
had earlier been released. Data collected were on: incidence and severity of
cassava green mite and phytoseiid; weather and soil physical and chemical
properties. The paired comparison design was employed with the sprayed and
unsprayed (presence or absence of phytoseiid) as treatments and sampling
sites as replicates. Subplots measured 25 x 15 meters with a minimum of 250
cassava plants. The incidence, severity and population of the cassava green
mite were observed to be highest in the dry season or short dry spell in the
rainy (wet) season. Rainfall and severe drought acting indirectly on food
availability to cassava plant were noted to be important mortality factors of
the pest. Available phosphorus and organic matter were observed to hinder
development and attack of the cassava green mite. However, soil nitrogen,
available phosphorus and organic matter significantly promoted the
development of phytoseiids. Temperature on the other hand had detrimental
effect on the general development of phytoseiids.
Selection and in-vitro propagation of five cassava (Manihot
esculenta, Crantz) cultivars
K. E. Danso1, E. Acheampong2, H. M. Amoatey.1
1Ghana Atomic Energy Commission, Biotechnology &
Nuclear Agric. Research Insti
Department of Plant & Soil Sciences, P. O. Box 80,
Legon.
2University of Ghana, Department of Botany, Legon.
ABSTRACT
Thirteen cassava cultivars were collected from farmers in the Greater
Accra Region using a structured questionanire. Five cultivars namely, Ankrah,
Bosom nsia, Biafra, Santom and Afisiafi were selected based on popularity,
duration to maturity and tolerance to African Cassava Mosaic Virus (ACMV)
disease. The cultivars were propagated in vitro using meristem, multiple
shoots culture, and somatic embryogenesis. Meristematic explants were
cultured on Murashige and Skoog (1962) basal salts and vitamins (MS) amended
with NAA 0.1 mg/l, GA3 0.1 mg/l BA (0.0-0.15
mg/l BA). There was profuse callus formation in all the cultivars. The
optimal concentration for shoot proliferation was 0.10 mg/l BA or 0.15 mg/l
BA. With reduced NAA and GA3 concentrations (0.02 and 0.04 mg/l respectively)
in the culture medium BA 0.05 mg/l was optimum with 100% and 46% shoot
regeneration respectively in Bosom nsia and Santom compared to 37% and 0% in
the ptevious treatment. All the selected cultivars formed multiple shoots
from single bud cutting of in vitro plantlets.
However, the number of apical shoots formed was dependent on BA
concentration in the medium. Embryogenic calli formation on MS amended 2,4-D
0.0-16 mg/l depended on the type of explants. For greenhouse grown plants
development of embryogenic calli from young leaf lobe and apical meristem
explants was significantly higher than stipule explants. However, none of the
calli were able to induce primary embryos when transferred to a maturation
medium (MS plus 0.1 mg/l BA). Similarly embryogenic calli formation from
tissue-cultured young leaf lobe explants on the same media were high in all
the 2,4-D treatments. Subsequent production of primary embryo was low on the
maturation medium and was found to depend on the cultivar and 2,4-D
concentration. Somatic embryo formation was higher on 2,4-D 16 mg/l medium
than on 4 mg/l or 8 mg/l 2,4-D medium. Santom produced the highest percentage
of embryo (25%) among the cultivars used.
Embryogenic calli which did not form somatic embryos formed roots
which depended on the 2,4-D concentration of the induction medium.
The effects of time of planting on the establishment
and development of oil palm seedlings – preliminary results
K. Baidoo-Addo
Oil Palm Research Institute, Post
Office Box 74, Kade
ABSTRACT
The effects of planting Dura X Pisifera (D X P)
crosses of oil palm seedlings at different times of the year on vegetative
growth were studied in a two-month interval planting system. Generally, for
all parameters, seedlings planted in May and July performed better than
seedlings planted in September and November. Apart from leaf area and leaf
area index the other parameters were not significantly different at the 5%
level. The agronomic implications on plantation establishment are discussed.
Storage
diseases of white yam (Dioscorea rotundata, Poir):
causes, varietal susceptibility and control
E. W. Cornelius and
K. A. Oduro
Department of Crop Science,
University of Ghana, Legon.
ABSTRACT
Decay in
three white yam varieties in Ghana ("Araba", "Asana" and
"Puna") stored for seven months were caused by Aspergillus
flavus, A. niger, A. oryzae, Botryodiplodia theobromae, Fusarium culmorum, F.
moniliforme, F. oxysporum, Penicillium brevi-compactum, Penicillium sp.,
Rhizopus stolonifer, and Erwinia sp. After seven months of
storage, "Araba" had a significantly lower (p = 0.05) rotting
percentage of 22.5% when compared with Asana (75.0%) and Puna (85.0%). In
studies aimed at controlling rot on bruised yams over a ten week period, lime
was found to be more effective than neem wood-ash (p = 0.005) in suppressing
decay in the three white yam varieties.
The effects of drying and
varietal differences on the physicochemical properties of cassava starch
Barimah, J.,1 Ellis, W.O.,1 Oldham,
J.H.,1 Safo-Kantanka O.,2 Pawar, G.D.1
1. Biochemistry Department, University of Science and Technology
(UST), Kumasi, Ghana
2.Crop Science Department, University of Science and
technology (UST), Kumasi, Ghana
ABSTRACT
Starch is a major component of cassava roots
and an important source of calories for human food and animal feed. The
physicochemical properties of starch from both fresh tubers and dried chips
of four cassava (Manihot esculenta Crantz ) varieties: Gblemoduade,
Abasafitaa, Isu-White and Afisiafi were studied to establish the effects of
drying and varietal differences on physicochemical properties. The parameters
studied were pH, solubility, viscosity, water-binding capacity (WBC), amylose
content and starch yield. Starch from fresh tubers did not show much
significant difference in amylose content and pH, but there were significant
differences in the viscosity and water-binding capacity values of fresh
cassava varieties. The same trend was observed for starch from the dried
chips. However, there were significant differences in properties between
starch from dried chips and those from fresh tubers for a given variety of
cassava. With the exception of WBC and solubility values which were higher
for starch from dried chips, the values obtained for other properties were
lower than starch from fresh tubers. Gblemoduade which had the lowest yield
of starch gave the highest values for most of the properties studied. The
results indicate that drying of the chips and varietal differences have some
profound effects on the starch quality and yield.
Incidence of fusarium wilt
disease of oil palm in some parts of Ghana
S. M. A. Tagoe
Oil Palm Research Institute,
P. O. Box 74, Kusi/Kade.
ABSTRACT
A
survey was carried out on fields belonging to the Oil Palm Research Institute
(OPRI) at Kusi, and Okumaning, and the Crops Research Institute (CRI), at
Akumadan to identify trees showing symptoms of Fusarium wilt and to
ascertain the extent of spread of the disease.
Out of a total of 41,113 trees from fields (K1 to K16) Surveyed at
Kusi, 57 or 0.14% of trees were affected by Fusarium wilt.
At Okumaning, out of a total of 3,157 trees, 9 (0.29%) had wilt.
Out of 768 trees observed at Akumadan, 54 (7.03%) showed symptoms of
the wilt. The genetic origin of the planting material and the environmental
conditions at the locality plays a very important role in the development of
wilt. Higher numbers of oil palm
trees in the drier environment like Akumadan were infected with wilt than
those in the wet areas.
The effects of water stress
on the chemical composition of soybean shoot parts at different growth stages
and assimilate distribution to the seeds at different nodal positions
J., Ofosu-Anim, 1 K. Asanuma, 2
and T. B. Bayorbor, 3
1 Department of Crop Science, University of Ghana,
P.O.Box 44, Legon
2 Crop Science
Laboratory, Faculty of Agriculture, Kagawa University, Miki-cho, Japan 761-07
3 Faculty of Agriculture, University of Development Studies,
Tamale
ABSTRACT
The response of soybean [Glycine max (L)
Merrill] cv. Akiyoshi to three moisture levels at three growth stages was
investigated in a glasshouse experiment. Percent leaf nitrogen was
reduced by water deficit at late flowering and early podding but increased
after rewatering. This parameter was not affected by water deficit at early
flowering. Percent total available carbohydrate in the stem was reduced by
water deficit except at late flowering but also increased after rewatering.
Plants subjected to water deficit after early podding had higher available
carbohydrate in the stem at maturity. Percent oil content was slightly
increased in the seeds of plants subjected to water stress at early podding
but percent protein was generally reduced by water stress. Total oil and
protein yields were reduced by water deficit at all stages of growth. 14C
retention was highest in the seeds of the main stem and lowest in those of
the secondary branches, seeds at higher nodal positions on the main stem
contained more 14C. The amount of 14C in seeds of the
primary branches decreased with an increase in nodal position from the main
stem. Distribution of 14C assimilates into the seeds of plants
subjected to water deficit was reduced at all stages of growth. The resultant
decrease in assimilate distribution to seeds will lead to a reduction in
yield of soybean grown under conditions of water deficit.
Some propagation techniques
of Malayan bamboo production
B. N. Nuertey
Oil Palm Research Institute, C.
S.I. R., Box 74, Kade/Ghana
ABSTRACT
Investigations carried out at the Oil Palm Research Institute, Kusi on
some propagation techniques of Malayan bamboo production confirmed cuttings
as preferred planting materials over the suckers. It was also observed that
the upper end setts of the bamboo cuttings sprouted better than the lower end
setts. The number of tillers per cluster from plants nursed and transplanted
to the field after four months was significantly higher by the 30th
month after planting than for plants for which cuttings were planted
directly in the field.
Effects of Propiconazole (tilt) and pruning on
severity of black Sigatoka disease and yield of plantain
C. K. Bodakpui1, K. A.
Oduro1 and K. Afreh-Nuamah2
1Crop Science Department, University of Ghana, Legon
2University of Ghana, Agric. Research Station, Kade.
ABSTRACT
Pruning of diseased leaves and the use of Propiconazole (Tilt) - a foliar
fungicide with systemic properties were two different recommendations made by
the Ministry of Food and Agriculture to control Black Sigatoka currently an
important disease of plantain in the country.
The two methods were evaluated at the University of Ghana Agricultural
Research Station, Kade. Four treatments namely Tilt (0.125 g ai/1), Pruning,
Tilt (0.125 g ai/1) + Pruning and Control (neither chemical nor pruning) were
applied in a Randomized Complete Block Design experiment. Disease severity
based on percentage total leaf area attacked was for the control treatment on
the average 16% (13.1-19%) while it was 4.6% (2.9-6.2%), 5.1% (3.7-6.4%) and
3.8% (2.5-5.0%) for Tilt, Pruning, and Tilt + Pruning, respectively.
The Control was significantly different from the other three treatment
which were however not different from each other at 5 % significance level.
The total number of bunches harvested after 66 weeks were 54, 50, 52 and 47
with bunch weights of 453.0 kg, 392.2 kg, 405 kg and 249.1 kg for Tilt,
Pruning, Tilt + Pruning and Control, respectively.
No differences were observed in the three main treatments but
differences were noticed between them and the Control at 5 % level of
significance. The difference in
the bunch weight was due to the significant difference in the weight per
finger (0.258 kg, 0.245 kg, 0.253 kg and 0.186 kg, respectively) for the
treatments. There was no
difference in the number of fingers per bunch, which was on the average 26.1
for all the treatments. Correlation
analysis gave a negative but significant association (r = - 0.96) between
severity of disease and yield. Simply pruning and burning of diseased leaves
could be encouraged in the control of black Sigatoka in the absence of
chemicals which may be expensive.
Quality of Ghana herbal tea: microflora and control
measures
E. Owusu and G.T. Odamtten
Department of, University of Ghana, P. O. Box 55 Legon.
ABSTRACT
The microflora of Ghanaian herbal tea comprising dried leaves of Cinnamon,
Hibiscus and Citronella have been investigated under field and laboratory
conditions. Fungal species
isolated varied from one sample to another.
Sixteen fungal species were isolated from Hibiscus, belonging
to the genera Aspergillus, Cladosporium, Eurotium, Manoascus.
Paecilomyces, Penicillium, Septodochium,
Rhizopus and Syncephalastrum; thirteen fungal species belonging to the
genera Aspergillus, Cladosporium, Emericella, Monoascus, Penicillium,
Streptomyces, and Rhizopus were resident in Cinnamon tea while
nine fungal species belonging to the genera Aspergillus, Cladosporium,
Monoascus, Rhizopus and Syncephalastrum were encounted on Citronella tea.
Aspergillus species (A. candidus, A. fumigatus, A.
ochraceus, A. rubrum, A. terreus, A. wentii) predominated followed by Cladosporium
(C. herbarium, C. cladosporioides, C. macrocarpon).
Some potential pathogenic bacteria (Flavobacterium meningoseptium,
Pseudomonas cepacia, P. paucimobolis and Xanthomonas maltophila were also
encountered. Some of the aeromycoflora isolated from the farms from which the
tea leaves were harvested (Aspergillus candidus, A. fumigatus, A.
ochraceus, Cladosporium clasosporioides, C. herbarium, Penicillium digitatum,
Syncephalastrum spp.) also infected the dry leaf samples.
Gamma irradiation up to 5.0 KGy reduced the microbiological loads of
the tea samples by 2-5 log cycles. A
combination of low (£
75% ERH) storage ERH and packaging material (brown paper and transparent
polyphone) significantly lowered the moisture content of the dried tea
samples and increased their shelf life. Practical implication of these
findings are discussed and further studies suggested.
Preservation of yams by gamma radiation
David Bansa and Victoria Appiah
Department of Food Science &
Radiation Processing
Biotechnology & Nuclear Agriculture Research Institute, P. O Box
80, Legon.
ABSTRACT
Loss of yam in storage due to sprouting
is very high. There is the need to investigate the possibility of inhibiting
the sprouting of local varieties of yams using gamma radiation. The effect of
radiation on the storage yams and the functionality of the irradiated yams in
the Ghanaian food system was studied. Yams were purchased from a farm in
Nkwanta. Some of the yams were irradiated at an average dose of 120 Gy and a
dose rate of 114 Gy/hr. The irradiated yams were stored alongside
unirradiated controls in a specially constructed barn and on the ground as is
traditionally done by the farmers at ambient temperature for 6 months. The
stored yams were processed into some local food products, namely, boiled yam,
fried yam and fufu and sensory evaluation carried out on them using the
Hedonic Scale Test and analysed by Analysis of variance. Results indicated
that all the unirradiated yams sprouted by the 3rd month of storage. 6.2% of
the irradiated yams stored on the barn and 18.0% of those stored on the
ground sprouted. 2.26% irradiated and 8.0% unirradiated yams stored on the
barn compared to 22.0% and 12.0% respectively of the yams stored on the
ground got rotten within the storage period. Food products made from
irradiated yams were preferred to those made from the unirradiated yams in
terms of texture, taste, colour and general acceptability. The results
suggest that gamma radiation dose of 120 Gy effectively inhibited the
sprouting of yams for 6 months under tropical ambient conditions. There was
less rotting in the yams stored in the barn compared to those stored on the
ground. There was also less rotting in the irradiated yams stored in the barn
in comparison with the unirradiated ones. Food products made from irradiated
yams were judged better in quality than those made from the unirradiated
ones.
The vegetation and environment of the Kakum National
Park
J. K. Adomako and E. Laing
Department of Botany, University of
Ghana, Legon
The Kakum Forest Reserve (about 30 km Northwest of Cape Coast) is a Moist
Evergreen Semi-deciduous forests intergrade, with an area of 213.56 km2.
Five plots, each of size 25 m by 25 m, were used for the vegetation and
microclimatic studies. Profile diagrams show a three-tier arrangement of the
trees greater than 20 cm girth at breast height but the strata are not
clearly defined. The girth class distribution of trees > 20 cm
girth-at-breast-height depict a forest undergoing natural regeneration from
seed; lower girth classes have high numbers compared to low numbers in the
higher girth classes. Ordination of the plots revealed two main environmental
gradients Dry soil–Wet soil and High altitude-Low altitude. Carapa
procera and Cola chlamydantha show apparent negative correlation
which is largely environmentally imposed - Carapa procera prefers
swampy conditions while Cola chlamydantha prefers dry land. 14
families had a frequency occurrence of more than 3% with the Sterculiaceae
being the most abundant. The variations of temperature, relative humidity and
light intensity were slight under the forest compared to wide fluctuations in
the gap. The soils are most probably forest oxysol-ochrosol intergrades.
Determination of bending modulus of elasticity of Pterygota
macrocarpa K. Schum (Kyere) and Piptadeniastrum africanum (Dahoma)
using two International testing norms
Joshua Ayarkwa
Forestry Research Institute of Ghana (FORIG)
Box 63, UST, Kumasi.
ABSTRACT
Two different international testing norms, DIN52186 (1978) and ISO8375
(1985) were used to determine the bending modulus of elasticity (MOE) of Pterygota
macrocarpa K. Schum (Kyere) and Piptadeniastrum africanum
(Dahoma). The results from the two testing norms for each timber species were
highly correlated, with correlation co-efficients of 0.92 and 0.96 obtained
for Kyere and Dahoma respectively. The
MOE determined using ISO 8375 (1985), employing deflections within loading
points (i.e. within the shear free zone) was, however, significantly higher
than that determined using DIN 52186 (1978), employing deflections along the
whole specimen length, for both species at 5% probability level.
The difference in MOE’s may be attributed to the influence of shear
stresses in bending, in the case of specimens tested using DIN 52186 (1978).
The results indicate that, test standards which recommend computation of MOE
using total deflection along the whole length of the test specimen may
under-estimate the actual rigidity of a wooden member.
Rheophytes of Africa – A review
Ameka, G. K.1, Adomako, J. K1., De
Graft‑Johnson, K. A. A.2, Cheek, M3. and Swaine,
M. D.4
1 Botany Department, University of Ghana, Legon, Ghana.
2 Water Research Institute, CSIR, Accra, Ghana.
3 Royal Botanic Gardens, Kew, Richmond, Surrey, UK.
4 Plant and Soil Science Department, University of Aberdeen, Aberdeen
AB24 3UN, UK.
ABSTRACT
The unique biological group of rheophytes are plant species confined to
the beds and banks (below the flood level) of streams and rivers.
Rheophytes are poorly known in Africa and until now have hardly been
studied. A preliminary list of African rheophytes is presented. One hundred
and twelve species from 18 families are accepted as rheophytes for Africa and
their peculiar characteristics and distribution in continental Africa are
discussed. We wish to draw the attention of African botanists to this
fascinating, yet uninvestigated group of plants.
Biodiversity
studies in three
Coastal Wetlands in Ghana, West
Africa
A. A. Oteng-Yeboah
Department of Botany, University of Ghana
, P. O. Box 55, Legon – Ghana.
ABSTRACT
Plant biodiversity studies of three coastal wetlands in Ghana were made.
The wetlands are the Sakumo, Muni-Pomadze and Densu Delta Ramsar
sites. Each wetland is made up
of a flood plain which consists of salt marsh (about 20%), mangrove swamps
(between 15 and 30%), fresh water swamp (about 40 - 45%), and in some cases
grassland (20 to 40%). Densu delta site had the highest number of species
(136) as against 133 for Muni-Pomadze and 114 for Sakumo.
Forty plant families were represented by their species in all the
sites. However certain families
were restricted only to specific sites.
Nine of such families were in Muni-Pomadze, 3 in Sakumo and 2 in Densu
Delta. These families and their
species add uniqueness to each of the sites studied. Sesuvium
portulacastrum, Paspalum vaginatum and Sporobolus virginicus
were characteristic for salt marsh and fresh water swamps while Avicennia
africana was the dominant species in the mangrove swamp. For the strand, Ipomoea
pes-caprae, Canavalia rosea and Opuntia vulgaris were the
characteristic species. For the scrub vegetation, various woody plant species
dominated at the different Ramsar sites.
However, Azadirachta indica, a naturalised tree species, was
very well represented in all sites, and indeed dominated in the Sakumo Ramsar
site. It is expected that these studies will lay the strong scientific basis
for the future management and strategic plans for the sustainable development
of these three Ramsar sites in Ghana.
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