Two experiments, each lasting 6 weeks, were conducted to evaluate quality protein maize (QPM) as a feed gredient for broiler chickens. In Experiment 1, either normal hybrid maize (NM) or QPM was used as the sole source of protein and amino acids, and the diets were balanced for vitamins and minerals by the addition of a vitamin-mineral premix. These diets were compared with a balanced 21 per cent crude protein starter-finisher broiler diet. In Experiment 2, broiler chicks were fed combined starter-finisher diets of varying protein contents in which QPM replaced normal maize. The aim was to assess the potential for reducing dietary fishmeal incorporation as QPM replaced normal maize. In both experiments, feed and water were supplied ad libitum. The parameters measured included feed intake, growth rate, feed conversion efficiency, and carcass characteristics. The economics of broiler production was determined in Experiment 2. In Experiment 1, birds receiving QPM as the sole source of amino acids performed significantly better (P<0.05) than their counterparts fed on normal maize. QPM-fed birds weighed an average 708.0 g each at the end of the trials compared with 532.0 g for those on normal maize. The corresponding feed efficiencies were 4.28 and 6.55, respectively. Compared with birds on the

balanced diet, however, QPM was inadequate in supporting broiler growth. In Experiment 2, the use of QPM allowed the fishmeal to be reduced from 19.5 to 13.5 per cent without adversely affecting performance. It was cheaper to produce broilers using QPM than using normal maize.

Original scientific paper. Received 4 Apr 97; revised 12 Jan 98.

The changes in some physico-chemical properties of dehydrated plantain slices packaged in polyethylene and polypropylene pouches and stored, at 37 oC and 75 per cent RH, for 6 months were studied. Moisture gain, non-enzymatic browning, colour changes, puncture force, pH, ascorbic acid and total acidity were measured. The rates of moisture gain and decrease in puncture force were significantly faster (P < 0.01) in the plantain slices packaged in polyethylene than in polypropylene pouches. Correlation between the rates of decrease in brightness and the extent of non-enzymatic browning in the plantain slices, was better when packaged in polypropylene than in polyethylene pouches. The pH, total acidity and ascorbic acid content remained almost unchanged. The study indicated that the adverse changes in physico-chemical properties of the dehydrated plantain slices were less in polypropylene than in polyethylene.

Original scientific paper. Received 12 Sep 97; revised 18 Feb 98.

A study was conducted to determine effects of feeding autoclaved-broiler-litter-based concentrate diet (ABL) at 20, 40 and 60 per cent level of inclusion on the distribution of milk nitrogen and blood nitrogen fractions of Bunaji cattle fed guinea grass hay ad libitum. Nine lactating Bunaji cows (238.2 1 7.88 kg initial BW) in a 3 W 3 latin square design consumed Panicum maximum hay, ad libitum, supplemented with diets A (20 per cent), B (40 per cent), and C (60 per cent) ABL inclusion levels, respectively, in an 84-day experiment. Litter contained 20.32 per cent ash, 18.40 per cent crude protein, and 68.30 per cent neutral detergent fibre (NDF). True protein nitrogen (TPN) varied between 685.7 and 690.3 mg/100 ml milk and this constituted 94.55 and 94.10 per cent of total nitrogen (TN). There were consistent trends forlinear changes in several response parameters due to increased dietary feeding level of ABL. The protein nitrogen (PN) value expressed as the percentage of TN increased for cows fed diets A and C while corresponding values recorded for animals on diets A and B were similar (P>0.05). Non-protein nitrogen

(NPN) fractions gave 31.74, 37.82 and 27.92 per cent of non-casein nitrogen (NCN) for diets A, B and C,r espectively, but significant variations were considerable due to advancing lactation. The combined linear effect of crude protein and energy intake contributed significantly (R2 = 87 per cent) to the variation in the total protein content of the milk while TPN varied directly with total nitrogen and NPN (R2 =97 per cent). In conclusion, mixed broiler litter, cassava waste supplement increased the nitrogen content of milk of Bunaji lactating cows with higher TPN and casein nitrogen (CN).

Original scientific paper. Received 15 Nov 96; revised 12 Mar 98.

A study to determine the effect of Flemingia congesta and Leucaena leucocephala hedgerows, as sources of mulch, on the population of nematode species in an alley cropping system was conducted at the Crops Research Institute, Kumasi, Ghana from May 1991 to February 1994. Treatments comprised Leucaena leucocephala and Flemingia congesta hedgerows and a control (no hedgerows), arranged in a randomized complete block design with four replications. Soil samples were taken from both hedgerow and control plots and assessed for nematodes periodically. Plant parasitic nematodes isolated were Meloidogyne spp., Pratylenchus spp., Paratylenchus spp., Helicotylenchus spp., and Rotylenchus spp. Three years after planting

of hedgerows, significantly (P<0.05) higher populations of Meloidogyne spp. (367 per 100 g soil),

Paratylenchus spp. (92 per 100 g soil), Helicotylenchus spp. (8 per 100 g soil), and Rotylenchus spp. (308 per 100 g soil), were associated with L. leucocephala hedgerows than with Flemingia congesta hedgerows (42, 0, 83, 0 per 100 g soil) and the control (74, 50, 41, 0 per 100 g soil). These results clearly indicate that L. leucocephala is a good host for plant parasitic nematodes. On the other hand, F. congesta has qualities that suppress nematode populations. Thus, in alley cropping, studies on attributes other than improvement of soil fertility should be carried out on the hedgerow plant species before recommendation for adoption.

Original scientific paper. Received 22 Aug 96; revised 16 Mar 98.

Studies were conducted to investigate the influence of inorganic fertilizers on the yield and fruit quality of Citrus sinensis [L] Osbeck cv. Late Valencia at the Agricultural Research Station, Okumaning near Kade (ARS-Kade). The trees which were 30 years old, had been budded onto either Rough lemon, C. jambheri Lush (RL), Cleopatra mandarin, C. reticulata Blanco (CM), or Rangpur lime, C. limonia (RGL), rootstocks. The fertilizer treatments common to all the rootstocks were as follows: T1 (control, no fertilizer); T2 (96.4, 40.2, 201 and 70 kg N, P2O5, K2O and S/ha, respectively); T3 (204, 80.4, 402 and 135.6 kg N, P2O5, K2O and S/ha, respectively). In treatments T2 and T3, the fertilizers applied were 15-15-15, sulphate of ammonia, and muriate of potash. For RL, an additional treatment (T4) was applied as in T3 but

without S. The effects of fertilizer application rates on the pH, percent juice content, juice volume, total soluble solids (TSS), titratable acidity (TA), and TSS/TA ratio were investigated. Fertilizer application increased yield significantly, irrespective of rootstock. The increases ranged

between 89 and 122 per cent for RL; 23 and 72 per cent for CM, and 26 and 67 per cent for RGL compared to the no fertilizer application. For RL, ammonium sulphate as N source tended to increase yield more than urea. Increasing fertilizer rate resulted in significant yield increases, irrespective of rootstock. While the pH and TSS/TA ratio of the juice was increased, titratable acidity was decreased by fertilizer application. Except for CM, the highest juice volume was observed from T2. In addition, the TSS was highest at T2 while ammonium sulphate application increased the TSS content of the fruit more than urea, suggesting the importance of sulphur in improving fruit quality. Fertilizer application reduced the maturity period of the fruit as measured by the TSS/TA ratio. A minimum TSS/TA ratio of 10 is recommended for acceptance as maturity index for sweet oranges in Ghana.

Original scientific paper. Received 18 Aug 97; revised 15 Apr 98.

Seven exotic varieties of cassava, namely TMS 30001, TMS 91934, TMS 4(2)1425, TMS 30555, TMS 50395, TMS 63397, and TMS 30572 developed in IITA, Ibadan, Nigeria, and three local varieties, namely 'Ankra', 'Bosomensia' and 'Katawia' were evaluated for African cassava mosaic disease (ACMD) and cassava bacterial blight (CBB) resistance in five ecological zones of Ghana. The trials were conducted in experimental fields of Crops Research Institute at Fumesua (Forest zone) in 1988, 1989, 1990; Aiyinase (High Rain Forest zone), Pokuase and Ohawu (Coastal Savanna zone), and Ejura (Forest-Savanna Transition zone) in 1989 and 1990; Techiman (Forest-Savanna Transition zone); and Nyankpala and Damongo (Guinea Savanna zone) in 1990. ACMD and CBB damage at 3 and 6 months after planting were scored on a 1-5 scale based on the severity of the diseases. The exotic varieties were significantly more tolerant to ACMD across the 3 years at Fumesua as well as in 1989 and 1990 across all locations. For CBB in 1990, the exotic varieties were significantly more tolerant than the local varieties in the Coastal Savanna zone where CBB incidence and severity was relatively high.

Original scientific paper. Received 22 Oct 97; revised 28 Apr 98.

A cocoa-food crop intercropping trial was set up in 1988 at the Cocoa Research Institute of Ghana, Tafo. The effects of plantain, cassava, and maize as intercrops with cocoa only and in their various

combinations on the establishment, growth of the cocoa, and the profitability of the food crops were studied in a randomized block experiment with five replicates. Mixed hybrid cocoa seedlings were planted at 3 m W 3 m and Glyricidia maculata provided permanent shade in all plots. Three years after planting, the sole cocoa with Glyricidia maculata was inferior in growth to the cocoa interplanted with food crops. Cocoa in treatments which included maize showed superior growth and better precocity. Yield of each food intercrop with cocoa only was higher than when combined with other food crops. Sole cocoa gave less revenue equivalent to the operational costs during the establishment phase. The other food crop combinations with

cocoa gave net revenue gain in the first 2 years after planting. The economic evaluation of the food crop combinations indicated that treatments which included cassava were the most profitable.

Original scientific paper. Received 7 May 96; revised 15 May 98.

The nutritive value of raw Mucuna pruriens (var. utilis) was studied over a 4-week period using 168 broiler chicks at 28 days of age. They were individually weighed and then randomly allocated to four dietary treatments incorporating, respectively, 0, 50, 100, and 150 g M. pruriens per kg of diet. Feed and water were supplied ad libitum. Data were collected for feed consumption, growth rate, feed conversion, and mortality. In addition, the effects of M. pruriens on carcass and haematological characteristics of broilers were studied. The dietary addition of M. pruriens significantly (P<0.05) depressed broiler performance, including a lowered feed intake, poorer weight gains, and reduced feed conversion efficiency. The addition of M. pruriens also increased the weights of gizzard, liver, and intestines (empty). There were no apparent effects of M. pruriens on blood parameters: haematocrit, haemoglobin, total serum protein, globulin, and albumin. Overall, it was less eonomical to feed raw, untreated M. pruriens to finishing broilers.

Original scientific paper. Received 4 Apr 97; revised 21 May 98.

Severe edaphic stress adversely affects the general performance of shallots (Allium cepa L. var. ascalonicum cv. Tropix.) This study was conducted to determine the effect of water stress on the growth and yield of shallots under 12-h daylength. Pot-grown shallots in a glasshouse were subjected to four levels of water stress, viz., flooded, regular watering, and watering up to half and quarter the field capacity (pot water-holding capacity = 373 g) of the root medium. Flooded shallots recorded the highest growth rate, leaf area, and green leaf number. Regularly watered and flooded shallots had the highest relative water contents of leaf tissue. Number of bulbs and axillary buds were not significantly (P>0.05) different in all the treatments despite the stress.

The highest harvest index and bulb yield were, however, obtained in the regularly watered shallots. Water stress, thus, adversely affected shallot growth, maturation, and bulb yield under 12-h photoperiod, although tissue water content was relatively high.

Original scientific paper. Received 24 Jan 97; revised 27 May 98.

The prospects for using Flemingia macrophylla and Mucuna pruriens in combination with manual weeding during the establishment of young cocoa was investigated. The following treatments were compared: Clean weeding three times/annum + F. macrophylla planted in the inter-rows of cocoa and biomass used as mulch; clean weeding of cocoa lines (1 m wide) three times/annum + Mucuna cover crop; and clean weeding four times/annum. The use of Flemingia mulch in combination with manual clean weeding three times/annum resulted in large girths and taller cocoa plants than in plots where Mucuna was used as cover crop. The girth and height of the young cocoa seedlings in the Flemingia plots were, however, not significantly different from those in plots where weeds were manually clean-weeded four times/annum. Seedling mortality was lower in the plots with F. macrophylla (7 per cent) than in plots which had Mucuna cover crop (13 per cent). Flowering and jorquette formation occurred earlier in the Flemingia plots than in the other treatments. The potential biological benefits of using F. macrophylla in an integrated weed management programme in young cocoa and the application cost are discussed.

Original scientific paper. Received 16 Oct 97; revised 8 Jul 98.

Effect of water stress on expansive growth measured as leaf extension rate (LER) and plant height of five Selected lines of sugarcane (BD 83/019, BD 83/035, IB 85/43, USRI 86/4, and USRI 86/25) was investigated in a screenhouse trial at Unilorin Sugar Research Institute farm. The effect of water stress on biomass yield was also evaluated. Water stress was induced by differential watering intervals of daily, 4, and 10 days corresponding to 100 (no stress), 60 (moderate stress), and 25 per cent (severe stress) soil available water (determined gravimetrically). LER, hence leaf length and plant height, showed significant responses to water stress, decreasing when water is limiting. The results of this study also showed ontogenetic variations in

the responses of leaves at different positions to water stress. Similarly, there were genotypic differences in leaf and plant height responses of the investigated lines to water stress, which were found to be related to the effect of water stress on biomass yields of the lines. Consequently, it was concluded that measurement of expansive growth could be very useful for distinguishing between genotypes in their responses to water stress; hence, a promising technique for screening for drought tolerance in sugarcane. The advantages of the techniques are also discussed.

Original scientific paper. Received 1 Oct 97; revised 13 Jul 98.

Five homozygous lines of castor plant, namely RS1-Om, RN1-Om, RTl-2m, RSl- Owm, and RNl- Omb, were crossed to raise F1, F2, BC1, and BC2 generations. The hybrids were tested for hybrid vigour for two metric traits, viz; number of pods per plant and seed yield per plant. Highly significant hybrid vigour was detected for both traits in all the crosses. The contributions of additive and non-additive gene effects to both traits were also investigated. Additive gene effects were more relevant in the inheritance of number of pods per plant. The effects of the digenic interactions, coupled with the highly significant additive gene effects on number of pods per plant in most of the crosses, tend to suggest that improvement of the character can be enhanced by the use of breeding methods such as the reciprocal recurrent selection that would encourage the

concentration of genes involved in the inheritance of the trait. The contributions of dominance gene effects to the total genetic variance were positive and highly significant in both pod and seed yield per plant in all the hybrids. This would tend to favour hybridization and the use of first generation hybrids as an effective means of improving both traits in castor plant. Thus, reciprocal recurrent selection and the use of hybrid programmes are the breeding strategies suggested for the improvement of pod and seed yield in castor plant.

Original scientific paper. Received 30 Sep 97; revised 14 Jul 98.

Department of Animal Science, University of Ghana, P.O. Box 226, Legon, Ghana

A diagnostic survey was carried out among pig farmers in the Greater Accra Region to gain some understanding about the pig industry and its associated problems as well as how best these problems can be addressed. In all, there were 48 respondents. Most of the farmers (84 per cent) had between 11 and 150 animals of various sexes and age groups. Many dispose of boar (53 per cent) and sows (43 per cent) after 2 years of use. Most farmers (98 per cent) mix their own ration to feed their animals, albeit poor in quantity or quality or both. The major constraints identified were non-availability of feed or high-priced feed, water problem especially in the dry season, and financial problems due to non-availability of credit facility.

Original scientific paper. Received 4 Aug 97; revised 15 Jul 98.

Department of Animal Science, University of Ghana, P.O. Box 226, Legon, Ghana

The chemical composition and protein degradability of Antiaris africana, Delonix regia, Milletia thonningii, Khaya senegalensis, Griffonia simplicifolia, Ritchea reflexa and Securinega virosa as well as treated or untreated rice straw were studied. The rice straw was treated with either sodium hydroxide (4.42 per cent w/w) or urea (7.55 per cent w/w) was used in the treatment of the straw. Wethers averaging 23.2 1 0.60 kg liveweight and fitted with rumen canulae were fed with the straw and browse and 5 g sample placed in a nylon bag and incubated in the rumen. Data were fitted to the equation P = a + b(1-e-et) where P is extent of degradation at time t, a is percentage loss of water soluble component, b is percentage loss of water insoluble component, c is rate of degradation of component b, and (a + b) is the maximum percentage loss of protein. Significant differences (P<0.05) were observed in the chemical composition of browse, with protein values ranging between 13 and 22 per cent. For the straw, the crude protein ranged between 5 and 10 per cent. Similarly, significant differences (P< 0.05) were observed in the values of a, b, (a + b)

and c among browse and straw. For the browse, the values for a ranged between 11 and 25 per cent, b varied between 40 and 60 per cent, (a + b) varied between 51 and 84 per cent, while c ranged between 0.011 and 0.043 h-1. The corresponding range of values for the straw were 6.1- 10.5, 38-50, 44-61 per cent and 0.020-0.011 h-1 for a, b, (a + b) and c, respectively. The browse and shrubs are very good sources of protein supplements, especially when used with straws.

Original scientific paper. Received 4 Aug 97; revised 15 Jul 98.

Department of Animal Science, University of Ghana, P.O. Box 226, Legon, Ghana

The seasonal variation in the chemical composition of some browse and shrubs in the coastal savanna of Ghana was ascertained. The browse studied were Antiaris africana, Delonix regia, Milletia thonningii, Grewia carpinifolia, Ritchea reflexa, and Securinega virosa. Samples collected in mid-November1992, early February 1993, and mid-June 1993 corresponding to the peak periods of the minor rains, dry season, and major rains, respectively, were used. Samples were analysed for dry matter and crude protein (percent CP), neutral detergent fibre (percent NDF), acid detergent fibre (percent ADF), cellulose, acid detergent lignin (ADL), and in vitro dry matter digestibility (IVD). Significant differences were observed with season (P<0.05) but not

with species (P>0.05) with dry matter where the dry season values were higher than those of the major and minor rains. Dry matter content ranged between 33 and 40 per cent. Crude protein content was lower (P<0.05) in the major rains compared to the minor rains and dry seasons. It showed significant species (P<0.05) variation and ranged between 11and 22 per cent. No significant seasonal effects (P>0.05) were observed in the fibre components and IVD values, but significant species differences (P<0.05) were observed. The range of values were NDF 27-63, ADF 13-46, cellulose 10-31, ADL 2.5-41, and IVD 40-80 percent. Thus, browse and shrubs in Ghana have adequate protein levels that would make their contribution towards improving the dry season nutrition of ruminants very useful.

Original scientific paper. Received 4 Aug 97; revised 15 Jul 98.

The static gravimetric method was used to determine the moisture adsorption isotherm data, at 30 oC, of the food flours of cassava-starch, cocoyam, plantain, fermented maize meal, and blends of cocoyam, plantain, and cassava-starch for the aw range 0.1 to 0.9. The adsorption data obtained were fitted to the Brunauer-Emmett-Tetter (BET) and Guggenheim-Anderson-de Boer (GAB) models, by regression analysis, to estimate and compare the monolayer moisture contents of the food flours. The moisture adsorption isotherms were a mixture of Types I and II, according to the BET classification. The monolayer moisture content values, as predicted from the BET and GAB models, were comparable ranging from 4.13 to 7.61 per cent dry solids. The quality of the fitted models, as estimated by the relative percentage deviation modulus, clearly showed that both models can be used adequately to predict the monolayer moisture contents of the food flours.

Original scientific paper. Received 12 Sep 97; revised 20 Jul 98.

In an experiment lasting 7 weeks, 288 one-day-old unsexed broiler chicks were used to assess the effect of supplementary vitamin C on the performance and carcass characteristics of broiler chicks raised in a hot, humid environment. The birds were randomly alloted in equal numbers to four dietary treatments based on maize and fishmeal to which were added 0, 100, 150 or 200 mg vitamin C per kilogram, respectively. The diets were isocaloric and isonitrogenous, containing 12.51 MJ (ME) and 212.4 g crude protein per kg. Each treatment had three replicates. Feed and water were supplied ad libitum. Supplementary vitamin C had no significant effect on all the performance and carcass traits studied, including feed intake, growth rate, and feed conversion efficiency. No economic advantage was gained by adding vitamin C to broiler feed.

Original scientific paper. Received 22 Oct 97; revised 23 Jul 98.

Research and development note. Received 12 Sep 97; revised 18 Jun 98.

The proximate composition and mineral contents of cake samples of copra (Cocos nucifera) were determined. Mean values observed for moisture, protein, fat, and ash were 10.2, 20.6, 12.6, and 6.0 per cent, respectively. Calcium and phosphorus also gave mean values of 90 and 513 mg per 100 g sample, respectively.

Research and development note. Received 29 Sep 97; revised 18 Jun 98.

The nutrient contents of samples of shelled roasted kernel of oil palm (Elaeis guineensis) were evaluated by determining the proximate composition, free fatty acids, and mineral contents. The samples contained 8.7 per cent moisture, 50.1 per cent fat. 9.9 per cent protein, 1.2 per cent ash, and 3.8 per cent free fatty acids (calculated as lauric acid). The calcium and phosphorus contents were 346 and 567 mg per 100 dry sample, respectively.

Research and development note. Received 29 Sep 97; revised 18 Jun 98.

Two samples A and B of the oil of coconut (Cocos nucifera) were stored for 3 months under ambient conditions (24-28 oC). The changes in the levels of free fatty acid and peroxide values were monitored at monthly intervals in the 3-month period. During this period, the free fatty acid (calculated as lauric acid) rose from 0.2 to 0.6 per cent for oil sample A, and from 0.2 to 0.8 per cent for oil sample B. The peroxide values were less than 10 for either oil sample after 3 months. This indicated a shelf life of more than 3 months for both oil samples.

Research and development note. Received 29 Sep 97; revised 18 Jun 98.

Velvet bean is a vigorously growing leguminous plant used for food, cover crop, and for soil improvement. Eight accessions of velvet beans, namely: 1739, 1740, 1741, 1742, 1743, 1744, 1745, and 1746 were collected from the Ashanti, Eastern, and Upper West Regions between 1982 and 1983. They were planted for characterization and preliminary evaluation in a replicated trial at the Plant Genetic Resources Centre at Bunso in the Eastern Region of Ghana. Qualitative characters like flower colour, plant pigmentation, and seed colour showed variability. Quantitative characters included both vegetative and reproductive characters. Characters like hypocotyl length, days to 50 per cent flowering and maturity, pods per plant, pod length, and 100-seed weight all showed variability. Accessions 1739, 1740,1741,1742,1743,1744, and 1745 had medium to large canopies and flowered (74-154 days) and matured (142-189 days) late, attributes

which will make them good cover crops due to their vigorous vegetative growth. Accession 1746 had a light canopy, flowered early (49 days), set pod and matured early (118 days), and had high pods per plant (50.0).

Research and development note. Received 4 Apr 97; revised 2 Jul 98.