African Journals Online

JOURNAL OF THE GHANA SCIENCE ASSOCIATION

VOLUME 1 NUMBER 1, JULY 1998 ABSTRACTS

Factors critical for the growth of science in a society
John K. Eminah

University College of Education of Winneba
Department of Science Education

ABSTRACT

The purpose of this paper is to sensitize all stakeholders in Science Education in Ghana to the level of scientific literacy in the country through a discussion of the factors that promote the growth of science. Before this is tackled, the paper briefly discusses the importance of the conceptual and the methodological structures of science and contends that both need to be given equal emphases if science is to thrive in any society or institution. The history of science education reveals that six factors namely: interaction with nature; openness; the existence of the plurality of views; naturalistic explanations of phenomena; experimentation; record-keeping are critical pre-requisite for the advancement of science in any society. The paper discusses each of the factors by making reference to practices that fostered the scientific enterprise and kindled the flame of scientific and technological advancement in the developed countries. These are contrasted with practices in traditional societies in Ghana and elsewhere which act as barriers to the growth of science.

The place of native language in Science teaching and learning in the Junior Secondary Schools in Ghana

M.K. Amedeker

University College of Education of Winneba
P.O. Box 25, Winneba

ABSTRACT

The effect of limited English language proficiency on the learning of science is investigated for some Junior Secondary School (J.S.S.) pupils. Despite serious efforts put up by pupils to learn science, difficulties in speaking and writing English were factors that limited their performance in science. Two types of schools: an experimental school (where English language was widely spoken by teachers and pupils) and the public system schools (where the native language enjoyed popularity) were investigated. In one case, pupils were urged to use English language to express themselves and demonstrate their level of understanding in science. On the other hand pupils were given the opportunity to use the local language to express their understanding of lessons in science. The study found out that learning science could be facilitated when the pupils with low proficiency in English were given the chance to employ their native language as a tool for learning science. This study, therefore, calls on educational policy makers to consider integrating the use of native languages into the science curriculum at the J.S.S. level. This implies developing more native vocabulary in science.

Optimising growth in relation to light regime and development of "improved robusta" coffee

E.B. Frimpong, Y. Adu-Ampomah, J. Safo and S. Akuoko
Cocoa Research Institute. P.O. Box 8, New Tafo - Akim.

ABSTRACT

Coffee breeding at the Cocoa Research Institute of Ghana over the past decade has focused on the improvement of the local Robusta coffee which has poor agronomic attributes including low yield. These breeding efforts have resulted in the development of a clonal material which has consistently shown better establishment, faster growth and development and higher yields over the local robusta. The experiment being reported here forms part of a series of trials designed to investigate growth requirements of the improved clonal material so as to maximise its potential. Transplanted seedlings were grown under three levels of artificial shade viz:- 25, 50 and 100 per cent of full-day light (FDL). Shading was provided by slats of bamboo supported on wooden posts. Growth data was recorded at monthly interval. Biomass production under the 50% FDL treatments was significantly greater than the 100% and 25% FDL treatments. Seedlings grown under the 25% and 100% FDL were significantly taller than those grown under the 50% FDL treatment. There were no significant differences in stem girth between the treatments. Root biomass was significantly greater in seedlings grown under the 100 and 50% FDL treatments (differences between the 100 and 50 were not significant) than those of the 25% FDL treatment. The overall picture indicates that a nursing shade of 50% FDL should be provided during establishment of the improved robusta coffee clones. Interplanting with food crops should be managed such that optimum of 50% FDL could reach the coffee canopy.

'By-catch'- A problem of the industrial shrimp fishery in Ghana

F. K. E. Nunoo
Department of Oceanography and Fisheries, University of Ghana, P. O. Box 99, Legon.

ABSTRACT

Ghana has an important Industrial Shrimp Fishery which is based at the Tema fishing port. In March, 1996, I joined two of the shrimp trawlers (MV Benhill 10 and MV Benhill 3) to sea on a normal commercial fishing trip. Data was collected from three fishing grounds, off the Ghanaian coast, on the catch, by-catch and discards in addition to observations of fishing practices and behaviour. Except for times of mechanical failure or the need for repairs, trawling tended to be for long periods and were continuous throughout day and night. The trawlers fished in shallow waters (depths of between 18 and 37 m) and close to shore (between 2.8 and 4.0 nautical miles). The fish and invertebrate catches were diverse both at night and during the day. Catches also included substantial quantities of litter and occasional catches of sea snakes, sharks and a sea turtle. There was an enormous but variable amount (both in weight and numbers) of by-catch in hauls. A large portion of the by-catch was discarded with most of them already dead. The discards consisted mostly of small individuals which were either juveniles of commercial species or species which were of no commercial value. The practice of catching and discarding portions of the catch back into the sea, with little chance of survival, is viewed as posing a great ecological problem for the marine environment off the Ghanaian coast.

Preliminary studies of fishmeal type on the growth rate of the weaner pig

S.W.A. Rhule
Animal Research Institute, Achimota

ABSTRACT

Thirty-six Large White weaner pigs at an average initial liveweight of 10.0kg were used to test response of pigs to two sources of fishmeal in the diet. The pigs were fed till they attained an average final body weight of 20kg. Three diets contained anchovy fishmeal (AFM), anchovy fishmeal: pilchard fishmeal (AFM:PFM) or pilchard fishmeal (PFM). Average daily gains were 0.272, 0.302 and 0.310 kg/day (P> 0.05) with corresponding feed conversion efficiency of 2.62, 2.54 and 2.34kg feed/kg gain for AFM. AFM: PFM and PFM, respectively. Canned pilchard when declared unwholesome for human consumption may be used for feeding pigs.

Rice varietal screening: Relationship between certain Agronomic Parameters and Tolerance to Iron Toxicity

J. Owusu Nipah¹; O. Safo- Kantanka², M.P. Jones and B.N. Singh³.

¹Oil Palm Research Institute (C.S.I.R.)Box 74, Kusi-Kade.
²Crops Science Department, Faculty of Agriculture, University of Science and Technology, Kumasi, Ghana
³WARDA/ADRAO, BP 2551, Bouake 01. Cote D'Ivoire.

ABSTRACT

One of the limitations to the development of rice cuktivars which are tolerant to iron toxicity has been the lack of efficient screening techniques. Field and screenhouse experiments were carried out in Cote d'Ivoire between September 1994 and June 1996 to study the relationship between iron toxicity and some agronomic parameters, with the objective of improving the method of screening. Twenty eight varieties (treatments) were transplanted, 21 days after sowing, into adjacent iron toxic and non-toxic fields in Korhogo in northern Cote d'Ivoire. A randomized complete block design was used with three replications. Recommended rates of fertilizers were applied. Leaf symptoms of iron toxicity were scored using the IRRI scale (1 - 9). Data was also taken on the number of tillers at the maximum tilering stage, plant height at maturity and yield and its components. Iron toxicity symptoms ranged between 3-7. Significant relationships were observed between iron toxicity tolerances and reduction in plant height (r = 0.61) and reduction in yield (r = 0.63). No such relationship was however observed between iron toxicity tolerance and reduction in tillers. We conclude that reduction in grain yield and plant height are good criteria for assessing materials for tolerance to iron toxicity but reduction in tiller numbers is not.

Incidence of cassava root rot in the central region of Ghana

Y. Opoku-Asiama, G. A. Mbofung and D. H. A. K. Amewowor

ABSTRACT

A survey of the incidence of Cassava root rot in the Central Region of Ghana was conducted from August to November, 1995. The main objective of the survey was to evaluate the economic importance of cassava root rot diseases in cassava production. All the twelve districts in the region were covered by the survey. From each district twenty cassava farmers were randomly selected out of forty farmers and they were interviewed using a questionnaire. The questionnaire was designed to find out the knowledge of farmers on the cassava root rot. The results indicated that 68.4% of cassava farmers in the region were aware of the occurrence of cassava root rot on their farms while 31.6 had not encountered it. The survey revealed that both soft and dry cassava root rot were well established in the Central Region except in one district, Dunkwa-On-Offin. The average incidence of soft cassava root rot in the various zones studied were: coastal districts (Komenda-Edina-Eguafo-Abrem, Mfantsiman, Awutu-Efutu-Senya and Gomoa) 36%; the penultimate coastal districts (Abura-Asiefu -Kwaman Kese, Ajumako-Enyan-Esiam and Agona Swedru) 30%; mid-region districts (Assin Foso and Asikuma-Odoben-Brakera), 21% and Forest District (Upper Denkyira and Lower Denkyira), 15%. For the dry root rot the incidences by zones at dry root rot were: Coastal District, 47%; the penultimate coastal districts, 18%. Mid-region districts, 13% and Forest Districts 27%. Six fungi were found to be associated with cassava root rot in the Central Region. They were Fusarium sp (white and dark colony types), Cunninghamella sp. Mortierella exigua Linnem, Glioclachum fimbricatum Gilman and Abbott, and Polyporus sulphureus Bull. Ex Fr.

Weaning and establishment of pineapple (Ananas Comosus) plantlets in compost

P. Y. Adjei¹ and P.G. Alderson^{2 1}Kwame Nkrumah Univerrsity of Science and Technology Kumasi, Ghana. ²University of Nottingham, United Kingdom

ABSTRACT

Plant establishment ex-vitro is one of the most difficult aspects of tissue culture (in-vitro propagation). The paper reports on establishment after treatment with two different auxins in-vitro. About ninety-nine (99) percent of the transported plantlets successfully established in compost. Spiny individuals increased with higher NAA concentrations but leaf density decreased with higher concentration of the auxin. Spinelessness, however, increased with higher IBA than its NAA counterparts, with the highest leaf number at 1 mg/L IBA. The extension/growth of the original shoot on both IBA and NAA media were not significantly different. The highest leaf expansion was recorded on the 0.5 mg/L NAA.

Postharvest problems of tomato production in Ghana - Field studies of some selected major growing areas in Ghana

Ellis, W.O¹., Olympio, N.S²., Mensah, E³., Adu-Amankwa, P⁴. & Tetteh, A. Y¹

¹Dept. of Biochemistry, University of Science & Technology, Kumasi.
²Dept. of Horticulture, University of Science & Technology, Kumasi.
³Dept. of Agricultural Engineering, University of Science & Technology, Kumasi.
⁴Food Research Institute (CSIR), Box M20, Accra.

ABSTRACT

Lycopersicon esculentum, Mill, commonly referred to as tomato is a highly perishable crop. However, the rate and extent of spoilage depends on several factors. To overcome this problem there is the need to develop simple, cost-effective and easily adaptable preservation techniques and to do this requires a better understanding of the farm management system of farmers. A study was carried out to determine the current farm practices, postharvest problems, preservation methods and marketing practices of farmers. Surveys using questionnaires were carried out in selected major tomato growing areas in Ashanti and Brong-Ahafo regions. The results of the study show that tomato is cultivated mainly by male youth with basic educational background. Cultivation is on the average three times a year and it is mainly on rented plots. The `Power' variety is the predominant variety for cultivation in Ghana. There is also the rampant abuse of agrochemicals by most of the farmers. The farmers carry out neither on-farm nor off-farm storage of the fresh tomato fruits. The major postharvest problems of the farmers are the need for permanent purchasing outlets and the stabilization of the unit price per box of tomato. This calls for a significant look at the distribution system for tomatoes.

Evaluation of Basta (glufosinate ammonium ) for weed control in Coffee

F.K. Oppong, K. Osei-Bonsu, F.M. Amoah and K. Opoku-Ameyaw
Cocoa Research Institute of Ghana
P.O. Box 8, Akim-Tafo.

ABSTRACT

Studies were conducted into the efficacy of Basta (Glufosinate ammonium) for weed control in coffee plantations. In field studies at three different locations, the effectiveness of weed control with Basta was compared with Gramoxone (paraquat), Paracol (paraquat + diuron), Gardoprim (terbuthylazine) and manual weeding. Basta at the rate of 0.6 - 1.0 kg a.i./ha effectively controlled most of the weeds found in coffee growing areas of Ghana, over much longer periods than the use of paraquat at the rate of 0.3 - 0.6 kg a.i./ha. However both herbicides could not effectively suppress perennial weeds such as Imperata cylindrica, Panicum maximum, Commelina spp, sedges and saplings of some dicots. Paracol and Gardoprim suppressed these perennial weeds better than Basta or Gramoxone. Although the application of Basta at a rate of 1.0 kg a.i/ha was more effective in controlling weeds than Basta at 0.6 - 0.8 kg/ha or paraquat at 0.3 - 0.6kg a.i/ha, this was not reflected in the yield of coffee. Generally, controlling weeds with Basta did not lead to a significant increase in the yield of coffee over that of paraquat

Aggregation pheromone complex of the desert locust, Schistocerca Gregaria (Forskal) (Orthoptera: Acrididae): Current Status

Obeng-Ofori, D., ^1* Torto, B.,² Njagi, P.G.N.² and Hassanali, A.²

ABSTRACT

The most striking feature of the desert locust, Schistocerca gregaria (Forskal), is its ability to reversibly transform between two morphologically, physiologically and behaviourlly distinct phases: solitaria and gregaria. The solitary phase prevails in the recession areas as dispersed individuals in very low densities in scattered populations, feeding on a limited range of desert plants and reproducing only when environmental conditions are sufficiently favourable. The gregarious phase is characterised by highly cohesive behaviour, long distance migratory aptitude, polyphagy, synchronous and accelerated maturation and communal egglaying, making the desert locust such a devastating pest. Pheromones are implicated in the perpetuation of these gregarious characteristics. The aggregation pheromone system of gregarious S. gregaria is derived from the insects themselves and their faeces. This has been demonstrated in GC-EAD, GC-MS and behavioural assays. Behavioural assays show that two distinct sets of releaser pheromones modulate the aggregation behaviour of the desert locust: a juvenile aggregation pheromone specific to the nymphs and an adult aggregation pheromone specific to the adult stages. There was no sexual differentiation in the production or response to nymphal pheromone system. Young adults (immature adults) of either sex did not produce a stimulus with significant activity. Of the older adults (sexually mature adults), only the males produced the aggregation stimulus to which both sexes were equally responsive. The nymphal pheromone system consists of three sets of compounds: aliphatic C6C8-C10 aldehydes and their corresponding acids produced by the insects themselves, augmented by faecal phenols and guaiacol. The adult aggregation pheromone system consists of phenylacetonitrile, guaiacol, phenol and benzaldehyde. Mature solitary desert locust adults were also responsive behaviourally and electrophysiologically to the components of the adult pheromone system. Faecal volatiles are part of the aggregation pheromone complex. The nymphs aggregate in response to their faecal volatiles and to those of young adults but were indifferent to volatiles emitted from adult faeces. The young and older adults even showed less specificity; they were cross-responsive to each other's faecal volatiles and to those of the nymphs. Phenol and guaiacol were the most predominant electrophysiologically active compounds of nymphal and young adult faeces. Faecal volatiles of older adults contained phenylacetonitrile in addition to phenol and guaiacol. A better understanding of the gregarisation-solitarisation process could open up ways of interfering with the gregarisation behaviour of the desert locust and possibly help develop new intervention strategies for biorational management of the insect.

Measurement of some blood proteins of children as an index of Nutritional Status

K. Nsiah, K. K. Appiah, F. O. Mensah and J. P. Mensah-Kordieh

¹Department of Biochemistry, University of Science and Technology (U. S. T.), Kumasi
²Deceased: formerly of School of Medical Sciences, U. S. T. Kumasi

Serum total proteins and albumin of 83 Ghanaian children whose ages ranged from less than one year to thirteen years were measured using the biuret and bromocresol green dye binding methods respectively. The globulin levels were obtained by difference. The range obtained for total protein was 54.7-87.9 g/l, that of albumin was 33.2-56.4 g/l and globulin, 14.3-37.7 g/l. Using albumin level as a predictor of malnutrition, none of the experimental subjects was overtly malnourished. Cognisance was taken of the variation of protein levels with age, sex and other factors.

The relationships among National Socio-Economic Indicators and Child Health Statistics

W. B. Owusu
Department of Nutrition and Food Science, University of Ghana , Legon.

ABSTRACT

There are a lot of country-specific socio-economic and child health data available. However, these have not been regularly analysed for the interrelationships among these variables. The objective of this study was therefore to use data reported by the United Nations to assess the relationships among national socio-economic statistics on education, economic performance, health care, nutrition, agriculture and demography, and infant and child mortality rates, from 129 countries. The methods used in the assessment were descriptive statistics, principal component analysis, and multiple regression techniques. Results showed that the socio-economic indicators in developed countries were obviously better than in the developing ones. Under-5 mortality rate was observed to be a better statistical indicator of child welfare than infant mortality rates, and it was influenced significantly by a country's level of educational attainment, maternal mortality rate, gross domestic product, and inflation rate.

Studies on Traditional Cheese (Woagashie) Production in the Ashanti Region

Appiah F. L¹, Ellis, W.O.¹, Mathias J.², Oduro, I.¹.

¹Department of Biochemistry, University of Science & Technology, Kumasi, Ghana.
²Department of Animal Science, University of Science & Technology, Kumasi, Ghana.

ABSTRACT

Cheese production has been in existence for more than 4000 years as a way of preserving milk and also serve as a source of protein supply and food or meat substitute. In Ghana as in other Sub-Sahara African countries, traditional cheese termed 'Woagashie', is gradually gaining popularity. A study was thus carried out to obtain baseline information on the production and nutritional status of Woagashie in the Ashanti Region. The result showed that Woaghashie was produced and retailed by women. Major source of milk for production was from their own herds and the quality indicators for Woagashie are mainly colour, taste and smell. Sale of Woagashie was high (57%) and it was mainly packaged in polyethylene films. Patronage was mainly by illiterates due to the poor presentation and quality of the product. Woagashie was used mainly as a food substitute due to its nutritional benefits. With the exception of colour, both consumers and producers judged quality on the same basis. On the whole, shelf life of Woagashie was about a week or two depending on whether it is preserved by boiling or stored by refrigeration. Nutirtionally, Woagashie produced at UST using whole milk powder (UST I) had the highest moisture level (67.33%) with that produced at UST using fresh milk (UST II) having the least. However, it was the inverse for fat with UST II having the highest (36.80%) and UST I (17.49%) the least. For protein, the trend was as for the fat with UST II having the highest protein content (18.32 %). Ejura II had the highest ash content (1.80%) with Yeji having the lowest (1.39%). The study showed that Woagashie is a highly nutritious product which requires efficiency in production and effective storage.

Heavy metal pollution in marine mollusks from the coastal waters of Accra, Ghana

E. Nyarko¹ and S. M. Evans²

¹Department of Oceanography and Fisheries, University of Ghana, Legon ¹Dept. of Marine Sciences and Coastal Management, University of Newcastle-upon-Tyne, U. K.

ABSTRACT

Studies of heavy metals in four marine mollusks, Thais haemastoma, T. nodosa, Nerita senegalensis and P. perna, have been conducted. This involved the assessment of levels of heavy metal pollution from point sources in the Korle lagoon and the determination of the extent to which these metals are transported by longshore currents to neighbouring areas (i.e. La and Teshie). Samples were prepared following the method described in UNEP (1993) Reference methods for Marine Pollution Studies and analysed with a (Philips Pye Unicam) atomic absorption spectrophotometer for cadmium, copper, iron, lead and zinc. The results indicate that the levels of some metals notably lead, copper and cadmium exceeded the WHO recommended limits. Since coastal communites harvest at least whelks, but probably also other mulluscs for food, they are clearly under threat. No gradient patterns were detected from the Korle lagoon along the coast, suggesting that metal pollution in the study areas are from a variety of sources. There is some evidence of biomagnification of zinc and copper along the food chain. Implications on human health are discussed.

Heavy metal levels and physical parameters of drainage ways and wells in three mining areas in Ghana

A. K. Armah¹; G. A. Darpaah²; D. Carboo³

ABSTRACT

Levels of heavy metals (mercury, arsenic, cadmium, iron, zinc and manganese) and physical parameters (total suspended solids, total dissolved solids, conductivity and hydrogen ion concentration) of water sources (drainage ways and wells) associated with mining of gold, diamond and quarrying of granite were assessed for contamination. The results show that in the gold mining area of Tarkwa, Hg levels decreased downstream from 5.40 (x10-3) mg/l to 2.80 (x10-3) mg/l. Arsenic levels, in contrast, ranged from 6.70 to 9.00 mg/l with no indication of any gradient. Iron levels, like Hg, decreased downstream, varying from 6.25 through 5.38 to 3.50 mg/l. In the diamond mining area of Akwatia, no Hg was found in the water samples. Arsenic levels were quite high with a mean value of 10.20±1.70 mg/l. The stream sample registered the highest level of iron at 18.0 mg/l. At the quarry site in Accra, contrary to expectation, Hg was detected in an appreciable concentration of 5.20 (x10-3) mg/l in one of the water samples. Arsenic levels were also high ranging from 9.10 to 19.10 mg/l. On the physical parameters analysed, the total suspended solids measured were low for the three locations with no significant variation (65.2±7.6 mg/l) except one sample from the quarry area which recorded 124 mg/l. Conductivity was highest in the quarry samples (331-11,450 mS/cm) followed by the gold mining area (164-188 mg/l), and then the diamond mining area (30-111 mg/l). Hydrogen ion concentration (pH) were normal for all the samples ranging between 6.05 to 7.79 indicating a generally neutral aquatic environment for the three mining areas studied.

Inference of domain structure at elevated temperature in fine particles of monoclinic pyrrhotite (Fe7S8).

A. Menyeh¹ and W. O'Reilly^2
1Department of Physics, University of Science & Technology, Kumasi, Ghan
²Department of Physics, University of Newcastle upon Tyne, Newcastle upon Tyne, NE1 7RU, UK

ABSTRACT

The thermal variation of the number of domains (nd) for Fe7S8 particles (within the size range 1-30 mm and between 20 and 300°C), has been inferred from the room temperature analytic expression between nd and particle size (L), the temperature dependences of the anisotropy energy constant (K) and the spontaneous magnetization (Ms) and, an assumed expression for the domain wall energy (Ew). It is found that nd increases or decreases with temperature rise depending on whether the inferred K(T) dependence is based on many defects in a domain wall, controlled by the volume reduction effect or the magnetostatic effect respectively. In either case however, nd is very weakly dependent on T which therefore points to a fixed domain multiplicity in the Fe7S8 particles within the temperature range specified. Based on this conclusion, it is suggested that the nucleation or denucleation of domain walls may be difficult processes in the acquisition of thermoremanent magnetization (TRM) in Fe7S8 particles.

Effect of Integral Non-Linearity on Energy Calibration of Spectroscopy Systems.

I. J. Kwame Aboh, S. Akoto Bamford and F. G. Ofosu

Department of Physics, National Nuclear Research Institute, Ghana Atomic Energy Commission, Kwabenya.

ABSTRACT

The integral non-linearity (INL) of four spectroscopy systems, two integrated (A1 and A2) and two classical (B1 and B2) systems was determined using pulses from a random pulse generator. The effect of INL on the system's energy calibration was also determined. The effect is minimal in the classical system at high countrate, but is quite pronounced in the integrated system under similar conditions.

Lindane and Endosulfan residues in water and fish in the Ashanti Region of Ghana

¹S. Osafo Acquaah and ²E. Frempong

¹Deparment of Chemistry, ²Department of Biological Sciences University of Science and Technology, Kumasi, Ghana

ABSTRACT

Pesticide residue analyses were performed on water and fish samples from the River Oda in Besease, the River Aframso in Nobewam near Kumasi, the River Twetwe in Akomadan and the River Kowire at Agogo in the Ashanti region of Ghana. The sampling sites were in regions of intense farming activities in the closed forest zone of the country. Analysis of the pesticide residues was done by gas chromatography, with a 63Ni electron capture detector. The residue levels for lindane and endosulfan were determined from water samples and in the following fish samples: Oreochromis niloticus, Tilapia zillii, Barbus trispulis, Heterobranchus sp., Tiliapia busumana, Ophiocephalus obscura and Chana obscura. Lindane residues ranging from 6.4 to 35.2 ng/g were obtained for the water samples, and from 0.8 to 265 ng/l for the fish samples. These values are well below World Health Organization recommended safe values for water and fish samples.

Preliminary evaluation of some forest trees for cocoa cultivation

K. Osei-Bonsu and G.J. Anim-Kwapong

Cocoa Research Institute of Ghana, P. O. Box 8, Tafo-Akim

ABSTRACT

Some forest trees were evaluated for their propagation, growth rate and suitability to provide shade in cocoa farms. The tree species were initially selected on the basis of being widely distributed in cocoa growing areas of Ghana. Germination tests including various dormancy breaking techniques were used to raise seedlings. Ricinodendron heudelotii required pre-heating at 40°C for 12 days to achieve about 70% germination. The use of acid scarification for 24 hours achieved only 32% germination which was not different from the control. Other species like Newbouldia laevis, Spathodea campanulata, Alstonia boonei and Pycnanthus angolensis germinated without any pre-treatment. R. heudelotii showed better growth rates than the other species in the field. N. laevis and Antiaris africana were slow growing from seedling transplants. S. campanulata and R. heudelotii provided good ground cover speedily. However, R. heudelotii showed deciduous growth even in the sapling phase whilst S. campanulata did not shed its leaves but rather renewed the leaves gradually such that shade was better provided throughout the juvenile growth period. S. campanulata would therefore be a suitable shade tree species for establishing young cocoa farms. Further evaluation of the growth pattern, shade provision and mineralization of the litter from the species continues.

Vegetative propagation of Triplochiton scleroxylon - a basis for future genetic improvement

Theresa Peprah

Forestry Research Institute of Ghana, P. O. Box 63, Kumasi

ABSTRACT

Triplochiton scleroxylon K. Schum is an economic timber tree species native to West Africa. As viable seeds of this species are rarely available, vegetative propagation techniques have been developed for the species to overcome this difficulty of seed supply, and to encourage reforestation efforts. Two studies have been carried out to develop vegetative propagation techniques as basis for future genetic improvement of Triplochiton scleroxylon K. Schum. The studies sought to assess the rooting ability of leafy stem cuttings from coppice shoots from different stump heights and coppice shoots from budded/grafted, mature trees and saplings. Rooting percentage was significantly (P < 0.05) higher in the stump height of 0.5 m compared with heights of 1.0 m, 1.5 m and 2.0 m. The root length per rooted cutting and also root number per tooted cutting were found to decrease with increasing stump height. There was also significant difference (P < 0.05) between the rooting percentages of cuttings from different plant material. The root number per rooted cutting was higher in saplings than coppice shoots from mature trees. However, root length was highest in saplings grown under shade and lowest in cuttings from saplings grown under direct sunlight. The results indicate that coppice shoots should be taken at low stump height to ensure high rooting success. These results also suggest that rooting ability is strongly influenced by the origin of material, and the most appropriate in saplings grown under shade and lowest in cuttings from saplings grown under direct sunlight. Material for propagation for practical purposes also appears to be coppice shoots from either seedlings or felled mature trees.