College of Agriculture & Natural Resources

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Identification, partial characterization and some properties of a virus causing a mild mottle disease in soybean, Glycine max (L.) Merril. in Nigeria, and The evaluation of local and exotic cowpea (vigna unguicalata (L.) walp.) for grain legume viruses under natural condition in Kumasi, Ghana
(1984) Anno-Nyako, Felix Ofori
A filamentous slightly curved virus was isolated from naturally infected soybean, Glycine max (L) Merril at the International Institute of Tropical Agriculture. Under greenhouse conditions, the virus induced infection that ranged between symptomless to mild mosaic and mottle on soybean. The virus was readily sap transmissible to 11 out of 14 members of the family Legnininosae, 2 members each of the families, .Chenopodiaceae and Cucurbitaceae and 4 members of the family. Solanaceae. Its assay host was Chenopodium amaranticolor Coste and Reyn., which produced chiorotic local lesions in its inoculated leaves 5 to 10 days after inoculation. It was propagated in Nicotiana clevelandii (L) and N. megalosiphon Heurck and Mueller. Sap from systemically infected plants was infective after dilution to l0 but not l0. Virus in crude sap had a thermal inactivation point of between 55°C and 60°C for 10 minutes and longevity in vitro of 8 days at 25°C. The virus could not be transmitted by the aphids, Aphis craccivora Koch and Myzus. persicae Sulz. However, the whitefly, Bemisia tabaci Genn was found to be an efficient vector of the virus. It could acquire the virus, in 1 hour acquisition access period and transmit the virus in a semi- persistent manner retaining the virus for 2 to 3 days. A minimum inoculation access period of 5 minutes was observed. The virus was 100% transmissible through seed of soybean Glycine max varieties ‘Malayan’ and ‘TGm 22-3’ as well as in Canavalia ensiformis (L.) DC. The virus had particles whose modal length was 646 nm and a width of 12 nm. Purified virus suspension had a typical ultra violet absorption curve of nucleoproteins with a maximum absorption at 264 nm and a minimum absorption at 247 nm. The E max/E mm ratio was 1 .13 while the E 260/E 280 absorption ratio was 1 .15 without correction for light scattering. The virus had a sedimentation’ coefficient of 158 S and average buoyant density of 1.31 g/cm3. It had an estimated extinction coefficient of 2.5 and percentage nucleic acid of 5%. The average molecular weight of the coat protein subunits was 32,000 daltons. Antiserum produced to the virus had a titre of 1/2048. A close serological relationship to cowpea mild mottle virus originally isolated from cowpeas in Ghana (Brunt and Kenton, 1973) could be established. The virus was also distantly related serologically to chrysanthemum virus B, but not to six other morphologically similar viruses. The virus has a Cryp gram of R/1: */5: E/E : S/AL. and is an isolate of cowpea mild mottle virus in soybeans. The virus has .Calopognium mucunoides, Centoseme pubescens. C. plumeiri, Desmodium scopirius, volunteer soybean and cowpea as alternate hosts and virus reservoirs,
Improvement of quality of cocoa beans (Theobroma cacao) through controlled fermentation
(1996) Ahulu, Evelyn Matekwor
The purpose for which cocoa beans are fermented is to produce beans with good flavour, aroma and taste for making such cocoa products as chocolate, beverages etc. This study was designed to (i) isolate and identify lactic acid bacteria (LABS) from fermenting cocoa which are one of the microorganisms responsible for the fermentation of the beans, (ii) to attempt to modify the fermentation factors using the LABS exclusively in singles and in combination to enhance the efficiency of fermentation so as to improve bean quality. To achieve the above objectives, field and laboratory experiments were carried out. The field experiments sought to monitor the temperature profile, microfloral population of the fermenting cocoa heaps and isolate and identify the lactic acid bacteria present in the three experimental areas. The laboratory experiments were mainly to ferment sterile cocoa using the four different bacterial isolates in singles or in combination at 2.6 x 108 cells of bacterial suspension per kilogram of sterile fresh cocoa beans. In the field, the results indicated that generally there was a significant difference between the mean temperatures of the top and middle of the, heaps, the top having the highest and the bottom having the lowest temperatures. The mean temperatures, of the heap were also seen to increase with time of fermentation. On MRS agar, it was observed that the bacteria increased within 48 hours and then decreased on turning the heap before the organisms increased slightly until the end, of fermentation. On malt extract agar, however, there was a gradual decrease in their numbers until none were observed as the end of the fermentation period. Lactic acid bacteria isolated were of the genera Lactobacillus, Streptococcus, Leuconostoc and Pediococcus. The laboratory experiments produced generally cocoa beans of good quality in terms of pH, moisture content, anthocyanin content and “cut” test results of the fermented and dried cotyledons of the beans. The results suggest that lactic acid bacteria used exclusively in fermentation of cocoa may improve the already good flavour of cocoa and probably come out with new flavours in cocoa depending on the different combinations or single bacteria isolates used. Other microorganisms like yeasts which are also some of the microflora in cocoa fermentation can act with these bacteria metabolites and may bring about changes in the quality of fermented beans. The yeast study is to be verified in a subsequent research.
Biological nitrogen fixation in legume - cereal intercropping systems
(1998) Kaleem, Fezrat Zenabu
In West Africa legumes are important food crops grown mainly in association with maize, sorghum and millet. Although legume/cereal association is a common practice, nitrogen contribution by legumes in such cropping systems and in rotation with cereals has not been given much attention and there have been relatively few studies on the biological consequences of this association. In order to address these issues four sets of experiments were conducted for two seasons (1992/1993) at Ibadan, Zaria and Kano situated in the Forest, Guinea savanna and Sudan savanna zones respectively. The first experiment consisted of two soybean cultivars intercropped with maize; the second experiment consisted of two cowpea cultivars intercropped with maize; the third experiment, consisted of two soybean cultivars intercropped with sorghum; and the fourth experiment, consisted of three cultivars of cowpea intercropped with millet. In the first season the legumes in all the experiments were planted either as sole crops or intercropped with cereal (either on the same-row or on alternate-rows), with fertilizer nitrogen at three levels (0, 20 or 100 kg h-1). Soybeans were either uninoculated or inoculated with a mixture of Bradyrhizobium japonicum strains TAL 102, TAL 377 and TAL 379. Sole crops of the cereals were included as checks. In the second season, the fields were cropped to the respective cereals as test crops. The design used was randomized complete block with factorial treatments in three replicates. Nodulation was assessed at flowering. At physiological maturity the total dry matter and nitrogen yields were determined. Results of experiment 1 indicate that inoculation increased nodulation, grain yield, N2 fixed and %Ndfa of soybean, the response was higher in Bossier than in TGX1485-1D. Intercropping decreased nodulation, grain yield, total N uptake and N2 fixed by soybeans. However, the extent of decrease depended on the soybean cultivar. The two methods of estimating nitrogen fixation (i.e. the Total Nitrogen Difference and the Isotope Dilution), gave similar rankings of treatments in this experiment although the methods gave different estimates of N derived from nitrogen fixation. Intercropped soybean contributed more to the succeeding maize yield than sole soybean, the highest maize yield obtained (4125 kg ha-1 was from the treatment BPN1 (Same-row with 20 kg N ha-1 fertilizer). In experiment 2, cowpea cultivar 1T86D-719 produced higher nodule weights, grain yield, total N uptake, N2 fixed, and %Ndfa than Suvita-2. Intercropping with maize decreased nodulation, total dry matter, total N uptake, and N2 fixed by cowpea compared to sole crop. However, the extent of decrease was dependent on the cowpea cultivar. For example, nodule weight of IT86D-719 was decreased by 35% (same-row) and 46% (alternate-row); whilst that of Suvita-2 was reduced by 26% (same-row) and 5% (alternate-row). Grain yield of maize was increased by 58% when grown after 1T86D-7 19 and 15% after Suvita-2 compared with when grown after maize. In Experiment 3 results showed interactive effects of cultivar x inoculation, cultivar x nitrogen and cultivar x cropping system. Soybean cultivar TGX148 5-1D out yielded Bossier in all the parameters measured under all experimental conditions. Inoculation increased nodule weight of soybean cultivar Bossier by 77% and that of TGX1485-ID by 11%. Highest nodule weights, total dry matter yield, total N uptake, N2 fixed and %Ndfa by TGX1485-ID were obtained with 20 kg N ha-1 whereas those of Bossier were obtained with 100 kg N ha-1. Intercropping with TGX1485-ID on the same-row increased sorghum yield by 10 and 26% at the 0 and 20 kg N ha-1 levels respectively, but decreased the yield at 100 kg N ha-1. However, sorghum yields were reduced to 68, 71 and 78% that of sole sorghum at 0, 20, and 100 kg N ha-1 respectively, when grown with Bossier. Grain yields of sorghum increased by 14% when sorghum was grown after Bossier and 38% after TGX 1485-ID compared with when grown after sorghum. Results obtained in Experiment 4 show that cowpea cultivar IT89KD-245 out yielded Kanannado and IT89KD-2246 in almost all parameters measured. There were interactions of cultivar x nitrogen and cultivar x cropping system with regards to the parameters measured. For instance, intercropping increased the nodule weight of IT89KD-245 by 5% but decreased those of Kanannado (22%) and IT89KD-2246 (2 8%). Grain yield of millet was increased by 4% when intercropped on the same-row with IT89KD-245 but was decreased by up to 29% and 26% when intercropped with Kananriado and IT89KD-2246, respectively. IT89KD-245 fixed consistently the highest amount of N2 with an average of 47 kg N ha-1 which was 15% and 147% more than the amounts fixed by Kariannado and IT89KD-2246, respectively. The yield of millet on previous cowpea plots ranged from 1200 to 2440 kg h&’ while previous millet plots yielded 1440 kg h-1. The results of these experiments showed that the productivity of cereal and legume intercropping is dependent upon a number of factors, whose interactions should be considered in research work. Different genotypes of the same legume have been shown to have different capacities to nodulate and fix N2 under intercropping. For instance, large differences in nodulation in the field have been shown between genotypes of cowpea and soybean intercropped with maize, sorghum or millet. Given the lack of inputs commonly available to small holders in the tropics, particularly in Africa, legumes which fix N2 and grow well without the need for inoculation such as the promiscuous soybean cultivar TGX 1485-ID, are the best solution for the immediate future. Planting arrangement of legume on either same- row or on alternate-rows with cereal affected the growth and yield performance of both legume and cereal in the mixture. TGX1485-1D intercropped on same-row with sorghum showed more vigour and gave higher yields than on alternate-rows with sorghum, whereas the reverse occurred in the case of Bossier. Total N accumulation, which is a good indication of the total amount of N2 fixed, at least in soils with a poor capacity to supply combined N is probably the best criterion for selection programmes in these ecologies. More research work needs to be directed towards nitrogen and other elements partitioning in intercropping situation. Serious attempts should be made to enhance N2 fixation in grain legumes. There is the need for agronomists and plant breeders to work in close collaboration with microbiologists in the development of better legume /rhizobial combinations.
The effect of cottonseed supplementation and helminthosis on some biochemical and reproductive traits in djallonke sheep
(2001) Djang - Fordjour, Thomas Kwadwo
Eight experiments were conducted to study the effect of cottonseed supplementation and helminthosis on some biochemical and reproductive traits in Djallonké sheep in the semi-arid zone of Ghana. In each experiment, five ewes per group ‘were assigned to each of four treatments designated as Ti, T2 T3 and T4. T1---Ewes were dewormed and the diet of each supplemented with 200g of raw cottonseed; T2—Ewes were not dewormed but the diet of each was supplemented with 200g of raw cottonseed; T3—Ewes were dewormed but non-supplemented and T4-—Ewes were neither dewormed nor supplemented. All the animals on supplementation were fed in the morning and released to graze at pasture. Experiments 1-4 were conducted in the rainy season while experiments 5-8 were done in the dry season to study the effects of cottonseed supplementation and helminthosis on some biochemical and reproductive traits in Djallonké sheep and the performance of their pre-weaned lambs. In the dry season experiments ewes in their first month of pregnancy were used to study the effect of the treatments on their pregnancy. Experiment 2 involved nursing ewes that were selected on the day of parturition to determine their postpartum anoestrous duration in the rainy and dry seasons. The third experiment studied the effect of the treatments on the reproductive traits of gimmers selected at weaning during the rainy and dry seasons. Experiment 4 studied how the treatment effect on ewes influenced lamb pre-weaning performance of the pregnant ewes The parameters measured included feed intake, haemoglobin, packed cell volume, total protein, progesterone, urea, potassium, glutamic oxalotransaminase, cholesterol, alkaline phosphatase, helminth profile, the length of the postpartum anoestrous period, oestrous cycle length, age and weight at first mating, birth and weaning weights, pre-colostral haemoglobin, One month old haemoglobin, precolostral packed cell volume, one month old packed cell volume, pre-colostral total protein and one month old total protein were also measured. In experiment 1 (rainy season), the major helminths encountered included Haemonchus contortus (29.2%); Trichostrongylus colubriformis (25.2%); Oesophagostomum columbianum (17.8%); Ostertagia circumcinta. (14.4%), and Cooperia curtcei (2.8%). Both supplementation and deworming gave better (P<0.001) haemoglobin, packed cell volume, and total protein values in the pregnant ewes. The glutamic oxalotransaminase, alkaline phosphatase, potassium and urea levels were significantly raised (P<0.001) with supplementation and deworming. Deworming raised the level of cholesterol significantly (P<0.001) but not so in the case of supplementation. There was interaction effect between supplementation and deworming on urea (P<0.001), potassium (P<0.05) and cholesterol (P<0.05) levels while supplementation improved (P<0.001) parturition weight of the pregnant ewes, deworming did not. Mean live weight, dry matter intake metabolic size and metabolic intake did not differ significantly (P>0.05) between dewormed and non-dewormed ewes fed raw cottonseed During the dry season, the most prevalent helminths in pregnant ewes included Trichostrongylus colubrformis (37.6%), Oesophagostomum columbianum (17.8%), Ostatagia circumcinta (17.4%), Haemonchus contortus (12.2%) and S. papillosus (10.6%). Both supplementation and deworming gave better (P<0.001) Hb, PCV, and TP values. The GOT, K, and urea levels were raised (P<0.001) with supplementation and deworming. However CHOL and ALK levels were higher (P<0.001) with deworming but not affected significantly (P>0.05) with supplementation. Mean live-weight was similar for both dewormed and nondewormed pregnant ewes fed raw cottonseed. Ewes dewormed gave higher (P<0.001) dry matter intakes. During the rainy season study in experiment 2, the major helminths encountered in postpartum ewes included H contortus (26.7%); T colubriformis (24.7%); O circumcinta. (22.1%). and O. columbianum (9.9%). Both supplementation and deworming gave higher (P<0.001) Hb, and PCV, values in the postpartum ewes. Deworming did not significantly (P>0.05) affect TP levels. The GOT, ALK, CHOL and Urea levels were significantly raised (P<0.001) with deworming. Supplementation also raised the levels of ALK significantly (P<0.001) but not so in the case of CHOL, Urea and GOT levels. The only interaction effect between deworming and supplementation occurred with urea levels. Mean live weight, dry matter intakes and metabolic size did not differ significantly (P>0.05) between dewormed and non-dewormed post partum ewes fed raw cottonseed During the dry season, the prevalent helminths in postpartum ewes were H contortus (29.2%), T. colubrformis (25.2%), 0. columbianum (17.8%), 0. circumcinta (14.4%), and S. papillosus (6.2%). Both supplementation and deworming gave higher (P<0.0O1) ALK, Hb, and PCV, values. TP Urea and CHOL levels were significantly (P0.05). The K levels were raised (P<0.05) with supplementation but not deworming. There was interaction effect on Hb, PCV, urea and ALK levels between supplementation and deworming. Mean liveweight and metabolic size were similar (P>0.05) for both dewonned and non-dewormed post partum ewes fed raw cottonseed: Ewes dewormed gave higher (P<0.001) dry matter and metabolic intake values. In experiment 3, during the rainy season, the major helminths encountered in gimmers included H. contortus (39.0%); T colubrformis (22.0%); 0. columbianurn (15.6%) and 0. circumcinta (15.4%). Feed supplementation and deworming showed higher (P<0.001) PCV and TP values in the gimmers. Supplementation had no significant (P>0.05) effect on conception weight, K, urea and CHOL levels. There was significant (P<0.05) effect of interaction between supplementation and deworming on levels of GOT and urea. Mean live weight, dry matter intakes, metabolic size did not differ significantly (P>0.05) between dewormed and non-dewormed gimmers fed raw cottonseed. During the dry season study on gimmers in experiment 7, the most prevalent helniinths included H contortus (29.2%) 2”. colubrformjs (25.2%), 0. columbianum (17.8%), 0. circumcjnta (14.4%), and S. papillosus (6.2%). Both supplementation and deworming gave higher (P<0.001) ALK, Hb, and PCV, values. TP Urea and CHOL levels were significantly (P<0.00l) affected with deworming but not supplementation (P>0.05). The K levels were raised (P<0.05) with supplementation but not deworming. There was interaction effect on Hb, PCV, urea and ALK levels between supplementation and deworming. Mean live- weight and metabolic size were similar (P>0.05) for both dewormed and nondewormed gimmers fed raw cottonseed. Gimmers dewormed gave higher (P<0.00I) dry matter intakes than the non-dewormed. In the rainy season study in experiment 4 on lambs, birth weights were heavier (P<0.05) than in the dry season. Rainy season lamb birthweights were 1.7 ± 0.26 kg; weaning weight was 9.83+0.21kg; pre-colostral PCV, Hb and TP were 30.4±1.31%; 10.95±0.68g/dl and 6.98g/dl respectively while one-month-old PCV, Hb and TP were 24.05±0.96%, 10.28±0.39g1d1, and 6.930.22gfdl respectively. In experiment 8 to determine the effect of ewe worm load and cottonseed supplementation on pre-weaning performance of Djallonké lambs during the dry season, the average birth weight was 1.65±0.20 kg; lamb-weaning weight was 9.58±0.49kg. Pre-colostral PCV, Hb and TP were higher (P<0.05) in lambs from Ti than T3. Deworming significantly increased (P<0.05) PCV, Hb and TP levels. Both deworming and feed supplementation decreased (P<0.05) gluteraldehyde agglutination times in the lambs. Gluteraldehyde agglutination times were shorter (P<0.05) during the dry season than the rainy season. This study generally showed that cottonseed supplementation with deworming improved the performance of pregnant ewes, postpartum ewes, gimmers and the lambs of treated pregnant ewes. There were also significant (P<0.05) improvements in the biochemical parameters of non-supplemented non-dewormed sheep compared with the non-dewormed non-supplemented sheep in the northern zone of Ghana.
Documentation of traditional musical instruments: case study of Okuapenhene’s palace, Akropong-Akuapem
(2001) Otibu, Franklin Akuffo
Akuapem is located in the south of Ghana on the southern-most extension of the Togo Atakora Range. The Akuapem land is mostly rocky. Akuapem comprises of four diverse ethnic components. The Kyerepong Guan occupies the seven towns of Abiriw, Dawu, Awukugua, Adukrom, Apirede, Aseseaso and Abonse; whiles the other Guan people are Larteh-Ahenase and Larteh-Kubease. The Akans reside in Akropong and Amanokrom and Twi-speaking Guans reside in Mamfe Abotakyi, Mampong, Tutu, Obosomase, Ahwerease and Aburi. The people of Akuapem were originally concentrated on the ridge towns. As the population increased, they began to migrate to the outlying areas of the state. Major occupation for the people of Akuapern is farming. They cultivate mainly fruits, cereals, tubers and oil palm. The name “Akuapem” has three interpretations. These interpretations are “Nkoa Apem” (thousand subjects), “Akuw Apem” (thousand groups) and “Akuafo Apem) (thousand farmers). Akuapem used traditional musical instruments. The origins of traditional musical instruments are difficult to trace because some Akan drums are similar to those used by other ethnic groups in Ghana. There are beliefs that some repertoires
Effects of on-farm residues on pond water quality, productivity, and fish growth in an aquaculture ecosystem in Ghana
(2001) Ofori, Joseph Kitson
The effects of selected on-farm wastes comprising groundnut peel (GNP), cocoa pod husk (CPH), rice bran (RB) and a standard feed (wheat bran - groundnut peel mixture) which constituted treatments in this study on water quality, plankton composition and tilapia growth at three application rates of 150 mg/I, 75 mg/I and 32.5 mg/I, have been assessed in aquatic ecosystems. The ecosystem consisted of a pond in which open-ended cylindrical concrete tanks were placed on one end to enclose the pond bottom. In these tanks, effects of inputs were assessed using multivariate analyses in comparison to no-input controls. The investigation tested the hypothesis that effects of on-farm wastes when applied singly to freshwater ponds impact differently on the water quality, phytoplankton, zooplankton and tilapia growth. The degradation rate constants of the on-farm wastes and their medium term effects on water quality were also assessed in glass aquaria under laboratory conditions. Following the determinations of the degradation constants, interactions and relative effects among water quality parameters; phytoplankton and zooplankton variables and the specific growth rate of tilapia were evaluated using the multiple regression approach. Comparative evaluations of plankton composition, periodicity and diversity for the various treatments in tanks were also studied Degradation rate constants K as determined from short-term biological oxygen demand (BOD) measurements for the inputs applied at application rates of 32.5 mgfl, 75 mg/I and 150 mg/I, were groundnut peel (GNP): 0.052, 0.058 and 0.065 per day; cocoa pod husk (CPH): 0.420, 0.037 and 0.057 per day and Rice bran (RB) 0.032, 0.036 and 0.057 per day respectively. Application of the different on-farm wastes resulted in changes in water physico-chemical parameters especially, that related to dissolved oxygen (DO), ammonia and phosphate. DO levels were low in all treatments at rates of 150 mg/I. Significant changes were also detected in total alkalinity levels (p<0.05). However, total alkalinity decreased with decreasing application rates. There was no significant difference in pH among treatments. GNP treatments recorded higher ammonia values at 150 mg/l. Although phosphate levels were high at rates of 150 mg/l which lowered C:P ratios below 20:1 in all tanks, it did not result in increases in blue green algae Phytoplankton counts differed for the various treatments showing the pattern of population density as GNP’CPH>Control>Stanfeed>RB with chlorophyceae and euglenophyceae dominating Phytplankton periodicity was not different for most of the treatments except in GNP Zooplankton (dominated by copepoda cladocera and ostracoda) had low diversity at higher than lower input rates Multiple regression analyses of water quality and plankton predictors both separately and jointly, on tilapia growth indicated that, generally water quality variables in groundnut peel and cocoa pod husk treatments explained over 58% of the variance, but less than 20% was explained in rice bran treatment. Over 50% of the variance was explained in stanfeed as against almost 73% in the controls by water quality variables. Nitrogenous compounds especially ammonia, nitrite and nitrate together with phosphate were the main water quality predictors that influenced growth in the different treatments. Stepwise addition of plankton variables to the regression, however, resulted in changes in the significant water quality that affected growth. Zooplanktons were significantly affected more by phytoplankton variables than by water quality in all treatments except the control. The results suggested that factors relating to water quality and plankton in semi- intensive culture express their effects on tilapia growth differently through both direct and indirect regulation of food organisms or improvement in the medium for the fish.
The effect of different tillage practices on soil erosion, water conservation and yield of maize in the semi-deciduous forest zone of Ghana
(2004) Adama, Abdulai Iddrisu
A study was carried out to assess the effects of different tillage practices on soil loss fertility erosion, runoff, in-situ moisture conservation, water use efficiency and crop growth and yield. The 3-season experiments (2000 major, 2000 minor and 2001 major seasons) were conducted on runoff plots at the Research Farm of the Department of Crop Science, Kwame Nkrumah University of Science and Technology (KNUST), Kumasi. Twelve (12) runoff plots (30m long and 4.0m wide constructed on an average slope of 6°h and fitted with measuring devices were used for the experiment. The area is within the semi-deciduous forest zone of Ghana with mean annual rainfall ranging from 1,300 to 1,400 mm. The treatments were: LT - Local Tillage by Hoe R-ALS - Ridging Along the Slope P-HACS - Ploughing and Harrowing Across the Slope T-RALS - Tied-Ridging Along the Slope R-ACS - Ridging Across the Slope BARE - Bare control plot ploughed and harrowed along the slope. All ridges were 50cm high and spaced at 80cm apart. Ties were 30cm high and spaced at 4 Om apart along the ridges. The treatments were studied in a randomized complete block design (RCBD) with two replications. The Results were analysed by ANOVA and the Duncan’s Multiple Range Test (DMRT) was used to test the significance of mean differences. Regression analysis was used to establish relationships between measured parameters. The test crop was maize (Zea mays) variety GIDABA. The soil was Akroso series classified as Haplic Acrisol (FAO/UNESCO). It is a sandy loam (top soil) to sandy clay loam (subsoil). The parameters measured included bulk density, particle size analysis; runoff and soil loss; nutrient and organic matter losses; crop height, stover, above ground dry matter and grain yields; harvest index and water use efficiency. The mean bulk density at the 0 - 20 cm depth immediately after land preparation ranged from 1.20 to 1.40 gcm-3 with a rank LT (1.4)>BARE (1.31)>P-HACS (1.30)>R-ACS (1.22)> T-RALS (1.20) = R-ALS (1.20). Bulk density at the 20 - 45 cm depth was 1.60gcm-3 for all treatments. At harvest, bulk density increased almost to the initial values (1.55 — 1.60 gcm3) recorded before land preparation. The respective range of runoff for the three seasons 2000 major, 2000 minor and 2001 major were 39.4 - 142.0 mm, 5.6 - 39.6mm and 28.3 - 78.7 mm for the R-ACS - BARE. The magnitude of runoff was in the order of BARE>LT>R-ALS>P-HACS>T-RALS>R-ACS. The differences in the first four treatments were not significant but were highly significant (P>0.01) for TRALS and R-ACS. Rain water storage ranged from 321.7 to 409.7mm and 119.3 to 200.9mm for the 2000 and 2001 major seasons respectively with treatments ranking as R-ACS>T-RALS>BARE>P-HACS>R-ALS>LT. In the 2000 minor season, all the treatments except R-ACS (4.7mm) recorded negative moisture storage. R-ACS and T-RALS recorded significantly (p>.0.01) lower soil loss than the other treatments for all the three seasons. Soil loss over the three seasons followed a decreasing order of BARE>LT>RALS>P-HACS>T- > Cumulative soil loss over the three seasons resulted in top soil depth loss of 10.8, 8.5, 7.4, 4.6, 2.0 and 1.4 mm for BARE, LT, R-ALCS, P-HACS, T-R.ALS and R-ACS respectively. Tillage practices significantly influenced nutrient loss. The concentration of nutrient tended to be higher with smaller soil losses. Total nutrient loss however increased with increasing soil loss. The total amount of organic matter loss during the three seasons ranged from 356.7 — 2314.5 kgha-1 with trend of BARE>LT>R-ALS>P-HACS>T-ALS>RACS. The total nitrogen loss in both the eroded sediment and runoff for the entire experimental period was in the order of LT>BARE>R-ALS>P-HACS>TRALS>R-ACS and ranged from 25.0 to 277.7 kg ha-1. In all the three seasons nitrate concentration and amounts in runoff was significantly higher than ammonium. Total available phosphorus (P) losses for the three seasons of experimentation ranged between 0.41 and 2.0 kg ha-1 with a trend of BARE> LT> R-ALS> P-HACS>T-RALS> R-ACS. Potassium losses range between 0.56 and 2.33, 0.03 and 0.34 and 0.38 and 3.36 kg ha-1 for the 2000 major and minor and 2001 major wet seasons respectively. The order of losses for the major seasons was LT>BARE>RALS> P-HACS>T-RALS> R-ACS. Apart from P and K, the differences in the enrichment ratios under the various tillage treatments were not significant. R-ACS and TRALS tended to record significantly (P>0.05) greater plant heights whilst R-ALS recorded the least. Maize grain yield in the 2000 major and minor and 2001 major wet seasons was in the range 1.7 — 2.8, 0.99 — 1.97 and 1.1 - 2.6 t ha-1 respectively. With a trend R-ACS>T-RALS>P-HACS>LT>R-ALS, the R-ACS and T-RALS consistently out yielded the remaining treatments. Relationships established between measured parameters showed soil loss to positively correlated with runoff (r2 = 0.81 - 0.89). Soil loss per ha-mm of runoff was 1.1 t ha-1. Soil loss and runoff were negatively correlated with their nutrient concentrations. The magnitudes of the correlation co-efficients were generally low. The total nutrient loss of each treatment (kg ha-1) was however positively correlated with runoff (r2 = 0.40 - 0.97) and soil loss (r2 = 0.63 - 0.99). Plant height was highly significantly (P>0.01) and negatively correlated with runoff (r2 = 0.92 - 0.96), cumulative soil loss (r2 = 0.99) and cumulative total nutrient loss (r2 = 0.87). Maize grain, stover and above ground dry matter yields were negatively correlated with runoff, soil loss and nutrient loss. Yield loss per kg ha1 against cumulative soil loss were 13.9 kg-ha-1 for grain (r2 = 0.89), 353.3 kg ha-1 stover (r2 = 0.80) and 49.3 kg ha-1 above ground dry matter (r2 = 0.88). A kg ha1 of cumulative total nutrient loss decreased grain yield by 4.6 kg ha1 (r2 = 0.62), 13 kg ha’1 stover (r2 = 0.71) and 17.6 kg ha-1 above ground dry matter (r2 = 0.73). There was a significant positive correlation between crop height and grain yield (P>0.05) and stover yield (P>0.01). A cm loss in crop height reduced grain (r2 = 0.89) and stover (r2 = 0.92) yields by 46.3 and 99.2 kg ha-1 respectively. The recommended choice of tillage practice for soil, water and nutrient conservation, improved biomass production and grain yield is in a decreasing order of R-ACS>T-RALS>P-HACS>LT>R-ALS. LT, as a prevalent tillage practice in smallholder farming systems should always be complemented by proper residue management and nutrient replenishment strategies.
Tilage and cropping systems effects on soil moisture, nitrogen fixation and yield of cowpea intercropped with maize in Northern Ghana
(2005) Kombiok, James Mantent
Results from research work on tillage systems conducted mostly in the rainforest and coastal Savanna zones under monocultural crop production systems have been conflicting. Against this background, experiments were conducted at Nyankpala within the northern savanna ecology to assess the influence of different tillage systems on soil properties, water storage, nitrogen fixation and crop yield. The experiments were laid in split-plot design with four replications. Tillage systems which consisted of Conventional (CON), Bullock Plough (BP), Hand hoe (RH) and Zero-tillage (ZT) were the main treatments. The sub-treatments were sole maize, sole cowpea, maize/cowpea inter-row cropping system and bare fallow in 2000 which was replaced in 2001 with maize/cowpea intra-row cropping system. The results showed that tillage loosened the soil and thus reduced soil bulk density, increased porosity and enhanced surface roughness. Bulk density and surface roughness were in decreasing order of ZT>HH>BP>CON and CON>BP>HH>ZT respectively. The ZT, which had a sparse vegetative cover due to bush tires in the preceding dry season, recorded the lowest surface roughness among the tillage treatments. The reduction in soil bulk density and the increase in surface roughness due to tillage reduced runoff and more water were stored in the deeper tilled than the shallow and the non-tilled treatments. The average reduction in estimated runoff over the two years experimentation was 54% in cowpea and 43% in maize under CON. More than 50% of the water in the 105 cm deep profile was stored at the 0-30 cm depth in all the treatments. Among the tillage treatments, CON and BP with greater working depths of not less than 12 cm stored more water than HH and ZT treatments. There was also a mean reduction of 50% by CON and BP in weed infestation compared to RH and ZT treatments. The ZT treatment significantly (P<0.05) reduced plant height and LAI of crops, which in turn reduced the amount of light intercepted, and the subsequent low dry matter yield produced by the crops on it. Calculated water use (ET) was higher for maize than cowpea. Water use efficiency (WUE) of maize for dry matter production at 8 WAP was significantly (P<0.05) higher under CON and BP than under HH and ZT treatments. A similar trend was observed for cowpea in 2000 but in 2001 ZT significantly (P<0.05) recorded a greater reduction of 42.8% in WUE. Grain yields of maize and cowpea did not differ between CON and BP but were significantly higher (P<0.05) than the grain yields of the RH and ZT treatments. The differences in land equivalent ratios (LER) among tillage treatments were not significant but each was more than 1 (>1) implying a substantial agronomic advantage over sole cropping system. Generally, there were no consistent increases of both nodule weight and nodule number per cowpea plant due to tillage at the 4 and 6 WAP but each of them declined at 8 WAP. Nodule weight was not affected by tillage but nodule number per plant was significantly lower (P<0.05) on ZT than CON, BP and HH treatments at 8 WAP. The percent nitrogen fixed by cowpea under each of the tillage treatments was higher than 50% but the differences among the treatments were not significant. Cropping systems had no significant influence on soil bulk density and water storage but bare fallow in 2000 significantly reduced (PCON>HH>ZT while in terms of cost it was ZT>CON>BP>HH. Among the cropping systems, the BCRs in sole crops were higher than their intercrops but the BCRs of inter-and intra-row cropped maize and cowpea were similar. Based on the results, the recommended tillage practice was BP. which is comparable to CON in soil water conservation and crop yields. Maize intercropped with cowpea was better than the sole cropping system since LERs were more than 1 (>1) but either inter- or intra-row cropped maize with cowpea would give similar results.
Components of variation, combining ability and heterosis in Ghanaian pearl millets [Pennisetum glaucum, (L), R.Br]
(2005-11-03) Akanchalekum, David Afribeh
Information on genetic variation is necessary in the breeding of plant populations for improvement. Two studies on genetic variation in pearl millet populations were conducted. In Study I, genetic variation and related parameters within four pearl millet populations, consisting of three local landraces (BLP, BSH and TY) and one base population (ICMV —bpl) were investigated by evaluating S1 progenies derived from each population at two locations in northern Ghana over two years. The main objectives were to determine the feasibility of selection within the populations and to recommend effective breeding strategies for their improvement. Significant genetic variations and low to moderate heritabilities were observed in the populations BLP, BSH, and ICMV bp —I, for grain yield, days to 50% blooming (maturity period), earhead length, plant height and 1000 grain weight and also for number of effective tillers per plant in BSH. However, genetic variation for most traits was not significant in the landrace population, TY. None of the landrace populations showed significant genetic variation for percent incidence of downy mildew disease, a major constraint to pearl millet production in Ghana. The results show that selection would be feasible, but with limited gains, within BLP, BSH and ICMV —bpl and that there would be little or no progress from selection within TY. The use of recurrent selection methods with progeny testing would be considered most appropriate, in view of the moderate heritabilities observed for most traits in the three populations. The genotype by location and genotype by year interaction variances were significant, which would require that superior genotypes to form improved varieties from the populations be identified by evaluating progenies at each specific location and within an adequate number of years, in order to develop adaptable improved varieties. The traits earhead length, plant height, 1000 grain weight and number of effective tillers per plant (only in BSH) had positive correlations with grain yield, while maturity period, incidence of downy mildew and incidence of chaffy tillers caused by stem borer had negative correlations with grain yield in most populations. Judging from these observations, tall plant height, long earheads, large grain size, short maturity period, low incidence of downy mildew and low incidence of chaffy tillers due to stem borer are factors with favorable effects on the yielding ability of most of the populations. In Study II, combining ability and heterosis among local and exotic pearl millet populations were investigated, by evaluating a set of 21 diallel crosses and their seven parents at two locations. The objectives were to determine gene action on traits, in order to determine appropriate breeding strategies and also to identify parents and crosses for population improvement and hybrid development programs. Only the SCA mean square was observed to be significant for maturity period, while both the GCA and SCA mean squares were significant for grain yield, earhead length and percent incidence of downy mildew, indicating that maturity period is governed solely by non-additive gene effects while all the other traits studied are governed by both additive and non-additive gene effects. However, the estimated Bakers’s ratio for grain yield was low, while those for the yield component traits were high, implying that grain yield is predominantly governed by non - additive gene effects, while the latter traits are predominantly governed by additive gene effects. In view of this, the breeding of hybrids, using the populations studied, would be a more productive approach for improving pearl millet grain yields, than population improvement. Three of the populations, namely TY, BLP and ICMV IS 90311 had the most significant GCA effects for desirable traits, indicating their suitability for use as parents in crossing to form source populations for improvement. Low to moderate levels of heterosis were expressed by the crosses for grain yield (up to 76%) and yield components. Crosses with the highest heterosis for grain yield and for most other traits were mostly the local-by-exotic crosses, while the local-by-local crosses had relatively low heterosis for most traits.
Conversion of Natural Forest to Cocoa Agroforest in Lowland Humid Ghana: Impact on Plant Biomass Production, Organic Carbon and Nutrient Dynamics
(2009) Dawoe, Evans
This study was conducted to assess the effects of forest conversion to shaded-cocoa system on plant biomass, nutrient fluxes and soil physico-chemical properties along a chronosequence (forest, 3, 15 and 30-year-old cocoa farms) in the Moist Semi-deciduous Forest Zone of the Ashanti Region, Ghana. It also explored farmer indigenous knowledge and perceptions of soils and soil fertility dynamic processes. Plant biomass and above-ground organic carbon and nutrient pools significantly declined following changes in land-use compared to soil pools. Tree biomass constituted the largest pool ranging from 12.7 ±1.6 Mg ha-1 for the 3-year-old cocoa system to 209.3±33.3 Mg ha-1 in the forest. Soil Organic Carbon (SOC) in 0-60 cm soil depth did not change significantly over a 30-year period and ranged from 49.0±2.3 to 67.4±1.1 Mg C ha-1 in 3 year-old shaded cocoa system and forest respectively. SOC significantly declined only in the top (0-10 cm) soil at 3 years after conversion but recovered at 15 years. Thirty-year-old shaded-cocoa systems yielded up to 151 Mg C ha-1 primarily stored in established trees (both cocoa and shade trees) and soil pools. Total N declined only in the 10-20 cm soil depth in 3 and 15 year-old treatments but remained stable in all other soil depths across the chronosequence while available P stocks declined significantly. Soil exchangeable Ca, K and Mg stocks remained relatively stable with a tendency to improve, and cation exchange capacity (CEC) and base saturation increased more or less along the chronosequence. Soil bulk density (gm cm-3) increased significantly with increasing age of plantation only for the top 0-10 cm soil layer but did not differ among sites for similar depths. Despite the apparent stability of soil C stocks and nutrients (0-60 cm) along the chronosequence, soil quality declined under cocoa land-use at 3 years. Microbial biomass demonstrated a strong seasonal variation. However, conversion of forest did not result in a significant decline in microbial biomass. Mean annual litterfall and stand litterstocks differed significantly among land-uses. Litterfall ranged from 5.0 Mg ha-1 in 3-year-old cocoa to 10.4 Mg ha-1 forest systems while stand litterstocks were from 3.6 to 5.9 Mg ha-1 in 3 and 15-year-old farms respectively. Annual decomposition coefficients (kL) were similar in cocoa systems (0.221-0.227) but greater under forests (0.354). Estimated nutrient inputs from litterfall was 4 to 165 kg ha-1yr-1 of P and Ca respectively in 15-year-old and forest plots respectively. Turnover of fine roots was 3,591, 1,427, 2,466 and 4,066 kg ha-1yr-1 for forest, 3, 15 and 30-year-old plots respectively. Nutrient inputs through turnover of fine roots were estimated to be 16-31 kg N ha–1year–1, 2 -5 kg P ha–1year–1, 9-36 kg K ha–1 year–1, 18-47 kg Ca ha–1year–1 and 3-25 kg Mg ha–1year–1 across the chronosequence. There were significant differences in incident rainfall, throughfall and stemflow chemistry. Mean annual inputs of nutrients fluxes in incident rainfall were 5.7 kg N, 0.14 kg P, 13.6 kg K, 9.43 kg Ca and 5.6 kg Mg ha-1 yr-1. Rainfall loading or net canopy exchange was negative for total N at all sites while concentrations of P and the basic cations increased in throughfall relative to incident rainfall. Throughfall on average constituted about 95% of the total solute inputs of rainfall origin to forest floor. The mean N and P input-output balances were negative showing the system’s ‘no external input’ character. Farmers in the study had a well-developed knowledge system of their soils and related fertility processes. They derived their knowledge from observable plant and soil characteristics namely; soil color, crop yield, water retention capacity, difficulty to work soil, type and abundance of indicator weeds, leaf color or deficiency symptoms observed on crops and presence and abundance of soil macro-fauna. The qualitative perceptions of farmers matched scientific assessment of fertile or infertile soils. The results suggest the integration of local and scientific knowledge to facilitate the processes for formulating policies and development plans for agriculture truly participatory, gender sensitive and collaborative approaches. Enhancement farmers’ capability to adopt improved farm management and land preparation methods is required to conserve the soil and sustain long-term productivity.
Relationships between Some Anatomical, Physical and Durability Properties of the Wood of Some Lesser Utilised Ghanaian Hardwoods
(2009) Quartey, Gladys Ama
This thesis is the result of a comprehensive study of some anatomical structures as well as some of the properties of wood utilization of selected species and the interrelationship amongst them. The natural durability of ten lesser-known West African Species, namely Albizia ferruginea (Guill. & Perr.) Benth. (Awiemfosamina), Amphimas pterocarpoides Harms (Yaya), Antiaris toxicaria Lesch. (Kyenkyen), Blighia sapida Koenig (Akye), Canarium schweinfurthii Engl. (Bediwonua), Celtis zenkeri Engl. (Esa), Cola gigantea A. Chew. (Watapuo), Petersianthus macrocarpus (P. Beauv.) Liben (Esia), Sterculia oblonga Mast. (Ohaa), Sterculia rhinopetala K. Schum. (Wawabima), and as reference Teak (Tectona grandis), were evaluated by the field test according to EN 252 (1989) for a period of 6 months. Structural size samples were tested for their mechanical properties according to EN 408 (2003). Their water sorption properties were determined at relative humidity conditions of 30, 45, 60, 75, and 90 % at a temperature of 25oC and compared with Albies alba, Picea albies, Fagus sylvatica (European species). Three of the ten species, Albizia ferruginea, Blighia sapida, and Sterculia rhinopetala were selected for anatomical investigations based on their performance in the durability and mechanical strength tests. Microscopic sections of the transverse and tangential planes were made on a Leica sliding microtome, stained and permanently mounted in Canada Balsam. The micrographs were analysed using the stereological technique described by Ifju (1983) and Steele et al. (1976). Maceration was also done. The results from the field test indicate that some of these less utilized species could be used as substitutes for the more standard commercial species in their end use applications. It was found that Albizia ferruginea was very durable, Sterculia rhinopetala was durable and Blighia sapida was moderately durable. A general trend found in the ten species was that, the denser the species the less water/moisture it takes up and the more durable it is, combined probably with specific polyphenolic substances. An exception to this trend was Albizia ferruginea, having the highest sorption of the three mentioned species but at the same time the highest durability and Sterculia rhinopetala the least. The best correlations found between the mentioned properties/features are between density and bending strength, followed by density and sorption, sorption and durability and to a lesser extent density and durability. As could be expected, durability (as a result of natural impregnation with protective substances) was in fact not completely correlated with density: Albizia ferruginea although the lightest of the three specially tested species, had the relatively highest durability according to the graveyard test. Blighia sapida was found to have crystals which could be harmful for working tools. This could explain its brittle behaviour under stress. It had a bending strength of 61.4 N/mm2 at a moisture content of 29 % with an average density of 0.899 g/cm3. A peculiar form of cell wall thickenings has been found in the vessels of this species with the help of scanning electron microscopy. In a third position, Albizia ferruginea had lowest bending strength of 50 N/mm2 at a lower average density of 0.740 g/cm3. In conclusion, Sterculia rhinopetala was used for a pedestrian bridge constructed at the KNUST campus in Kumasi due to its performance in most of the tests carried out and even though most of the tested lesser utilized species were not durable; their durability could be enhanced by impregnation with protective substances in order to be used for external applications.
Soil fertility and microbial biomass carbon, nitrogen and phosphorus dynamics under different amendments and cropping systems In Ghana
(2009-02-05) Logah, Vincent
Optimizing manure quality for increased food production on small holder farms in the upper east region of Ghana.
(2009-07-13) Ewusi – Mensah, Nana
The beneficial role of cattle manure to improving soil fertility has long been recognized. Its uses however have several drawbacks. One of such drawbacks is the nutrient content which is generally low and variable depending on the feed of the animal and manure management. This study focused on improving the quality of cattle manure for increased maize yields and consisted of five parts: 1. Assessment of the resource quality of cattle manure in seven districts of the Upper East region. 2. Composting of cattle manure. 3. Laboratory - incubation studies to determine nutrient release patterns of compost. 4. Field decomposition studies of buried compost in litter bags. 5. Assessment of the effects of compost, cowdung and NPK fertilizer on crop growth and yield. A survey was conducted in seven districts of the Upper East region using structured questionnaires to seek information on management practices likely to influence manure quality such as storage and handling. The survey revealed that nitrogen losses up to 100% were sometimes obtained by the time the manure was incorporated into the soil. An initial resource quality analysis of the manure sampled from the seven districts was conducted in the laboratory using standard protocols. The results indicated that N and P contents of the manure ranged from 0.27 to 1.14% and 0.28 to 0.76% respectively, which were all below the critical levels for net mineralization. Polyphenol levels on the other hand were lower than the critical value of 4%. Decomposition and nutrient release from the manure showed immobilization of total N during the first four weeks, suggesting the need to improve the quality by composting or by applying it in combination with mineral fertilizers. In an attempt to improve the quality of the manure, composting with Stylosanthes guinensis using the aerated pile method was carried out. Two main compost types (1:1 and 2:1 ratios of cowdung to plant material) were prepared. Total N and P contents of the composts at the end of study period ranged from 1.10 to 1.46% and 0.28 to 0.31% respectively. Mineralization studies on the resultant composts were conducted under laboratory (leaching tube method) and field (litter bag technique) conditions. Under laboratory conditions, both compost types showed net N and P immobilizations during the first two weeks of incubation. However, under field conditions, net N and P mineralization rates were observed throughout the study period for both compost types. Half life values (time required for 50% of the initial mass to decompose) of 8 and 10 days respectively were recorded for the 1:1 and 2:1 compost types. Furthermore, the 1:1 compost had a higher decomposition rate constant (k = 0.085) than the 2:1 compost (k = 0.056). In all cases, negative correlations were observed between the mass of composts remaining and nutrient released. The contribution of the composts to improving the fertility of the soil and hence crop growth was evaluated by comparing maize response to various rates of the composts with optimum mineral fertilizer combinations. The results showed that the 1:1 compost treatment at 3 t/ha, produced the highest maize grain yield (4.99 t/ha). Maize grain yields obtained from both compost types compared very well with NPK fertilizer suggesting that composting of cattle manure with Stylosanthes guinensis enhanced its quality and nutrient release potential for increased crop yield.
An Analysis of Yam consumption Patterns in Ghanaian Urban Communities
(2009-07-14) Aidoo, Robert
This study examined the major factors that drive changes in yam consumption patterns across income groups, seasons and urban centers in Ghana to inform food policy formulation. The study, among other things, sought to provide evidence on whether or not yam had become a luxury food commodity in Ghanaian urban communities. Special attention was also given to the question of whether household income allocation between males and females had any significant effect on yam consumption. Quarterly household panel data collected from four urban centers were used to conduct a complete demand system analysis by employing the Almost Ideal Demand system (AIDS) and Quadratic Almost Ideal Demand System (QUAIDS) models through the use of the Ordinary Least Squares (OLS) method. The study estimated yam expenditure elasticities for the pooled/aggregate data and the four different urban centers across different income groups to test Engel’s law. Results of the study showed that majority (>80%) of yam consumers in Ghanaian urban communities preferred white yam to yellow and water yams, and the most important reason for their preference was taste. Boiled yam (ampesi) was the most preferred yam product in Ghanaian urban centers followed by pounded yam (fufu). Rice was identified as the most important substitute for yam in urban communities. In a typical Ghanaian urban center, household food budget formed about 51% of the total household budget. Yam constituted about 12% of household at-home food budget and 13% of its away-from-home food budget. The shares of food budget that households allocated to yam generally increased during the peak harvest season and dropped during lean season across all urban centers in Ghana. Yam expenditure elasticity for the pooled sample was found to be inelastic (0.76), suggesting that yam is a basic food commodity in a typical Ghanaian urban center. Yam expenditure elasticity was lowest for Tamale (0.64), a less urbanized center, and highest for Accra (1.01), a more urbanized center. Generally, across urban centers, the study supported Bennett’s law which posits that households switch from less to more expensive calorie consumption as their incomes increase. However, in each particular urban center, Engel’s law was affirmed; yam expenditure elasticity was higher for low-income households and lower for high-income households. Yam expenditure elasticity was found to vary across seasons; yam was expenditure elastic during the lean season and expenditure inelastic during the harvest season. Women’s share of household income was found to be positively related to household yam budget share. Evidence from this study did not support the hypothesis of economies of household size with respect to household yam budget share when the pooled data was used for analysis. However, the hypothesis of economies of household size was supported in the seasonal consumption analysis where households were found to enjoy economies of size during the relatively yam abundant period of August to December and diseconomies of size during the lean season. The study showed that yam budget share was own-price elastic but expenditure inelastic. Urban households were more responsive to changes in yam prices than changes in household income, implying that the substitution effect is stronger than the income effect. The high price elasticity for yam budget share stresses the importance of food price changes for households, and it is important that households’ reactions are taken into account in the development of comprehensive agricultural and food policies in Ghana. Based on the findings of the study, recommendations have been made to help improve the Ghanaian yam sector and household food security in urban centers.
Conversion of Natural Forest to Cocoa Agroforest in Lowland Humid Ghana: Impact on Plant Biomass Production, Organic Carbon and Nutrient Dynamics
(2009-07-14) Dawoe, Evans
This study was conducted to assess the effects of forest conversion to shaded-cocoa system on plant biomass, nutrient fluxes and soil physico-chemical properties along a chronosequence (forest, 3, 15 and 30-year-old cocoa farms) in the Moist Semi-deciduous Forest Zone of the Ashanti Region, Ghana. It also explored farmer indigenous knowledge and perceptions of soils and soil fertility dynamic processes. Plant biomass and above-ground organic carbon and nutrient pools significantly declined following changes in land-use compared to soil pools. Tree biomass constituted the largest pool ranging from 12.7 ±1.6 Mg ha-1 for the 3-year-old cocoa system to 209.3±33.3 Mg ha-1 in the forest. Soil Organic Carbon (SOC) in 0-60 cm soil depth did not change significantly over a 30-year period and ranged from 49.0±2.3 to 67.4±1.1 Mg C ha-1 in 3 year-old shaded cocoa system and forest respectively. SOC significantly declined only in the top (0-10 cm) soil at 3 years after conversion but recovered at 15 years. Thirty-year-old shaded-cocoa systems yielded up to 151 Mg C ha-1 primarily stored in established trees (both cocoa and shade trees) and soil pools. Total N declined only in the 10-20 cm soil depth in 3 and 15 year-old treatments but remained stable in all other soil depths across the chronosequence while available P stocks declined significantly. Soil exchangeable Ca, K and Mg stocks remained relatively stable with a tendency to improve, and cation exchange capacity (CEC) and base saturation increased more or less along the chronosequence. Soil bulk density (gm cm-3) increased significantly with increasing age of plantation only for the top 0-10 cm soil layer but did not differ among sites for similar depths. Despite the apparent stability of soil C stocks and nutrients (0-60 cm) along the chronosequence, soil quality declined under cocoa land-use at 3 years. Microbial biomass demonstrated a strong seasonal variation. However, conversion of forest did not result in a significant decline in microbial biomass. Mean annual litterfall and stand litterstocks differed significantly among land-uses. Litterfall ranged from 5.0 Mg ha-1 in 3-year-old cocoa to 10.4 Mg ha-1 forest systems while stand litterstocks were from 3.6 to 5.9 Mg ha-1 in 3 and 15-year-old farms respectively. Annual decomposition coefficients (kL) were similar in cocoa systems (0.221-0.227) but greater under forests (0.354). Estimated nutrient inputs from litterfall was 4 to 165 kg ha-1yr-1 of P and Ca respectively in 15-year-old and forest plots respectively. Turnover of fine roots was 3,591, 1,427, 2,466 and 4,066 kg ha-1yr-1 for forest, 3, 15 and 30-year-old plots respectively. Nutrient inputs through turnover of fine roots were estimated to be 16-31 kg N ha–1year–1, 2 -5 kg P ha–1year–1, 9-36 kg K ha–1 year–1, 18-47 kg Ca ha–1year–1 and 3-25 kg Mg ha–1year–1 across the chronosequence. There were significant differences in incident rainfall, throughfall and stemflow chemistry. Mean annual inputs of nutrients fluxes in incident rainfall were 5.7 kg N, 0.14 kg P, 13.6 kg K, 9.43 kg Ca and 5.6 kg Mg ha-1 yr-1. Rainfall loading or net canopy exchange was negative for total N at all sites while concentrations of P and the basic cations increased in throughfall relative to incident rainfall. Throughfall on average constituted about 95% of the total solute inputs of rainfall origin to forest floor. The mean N and P input-output balances were negative showing the system’s ‘no external input’ character. Farmers in the study had a well-developed knowledge system of their soils and related fertility processes. They derived their knowledge from observable plant and soil characteristics namely; soil color, crop yield, water retention capacity, difficulty to work soil, type and abundance of indicator weeds, leaf color or deficiency symptoms observed on crops and presence and abundance of soil macro-fauna. The qualitative perceptions of farmers matched scientific assessment of fertile or infertile soils. The results suggest the integration of local and scientific knowledge to facilitate the processes for formulating policies and development plans for agriculture truly participatory, gender sensitive and collaborative approaches. Enhancement farmers’ capability to adopt improved farm management and land preparation methods is required to conserve the soil and sustain long-term productivity.
Local Domestic Chickens: Their Potential and Improvement
(2009-07-15) Adomako, Kwaku
This study was conducted to assess the potential of indigenous chickens and improve their performance in traits of economic importance by incorporating in them the naked neck and frizzle genes, and also genes from a commercial layer (exotic breed) through crossbreeding (local naked neck/frizzle males × commercial females). Study One A survey was conducted to assess the current performance of local chickens in the Ashanti Region of Ghana. One-hundred and thirty five (135) local chicken keepers from Bosomtwe Atwima-Kwanwoma, Ejisu-Juaben and Asante-Akim South Districts were interviewed. All the keepers practised the extensive system of production with flock sizes averaging 22 in the ratio of 4: 6: 12 for cocks, hens and chicks respectively. A small amount of feed supplement was given either everyday or occasionally. Mortality of chicks (between day-old and six weeks) and total mortality (annual mortality for the entire flock) were 50% and 65% respectively. The average weights of cocks, hens and eggs were 1.55kg, 1.13kg and 42.80g respectively. The clutch size per bird ranged from 9-13. The major challenges faced by the keepers included diseases, predation, lack of funds to increase stock and construct structures, small sizes of birds and eggs, low numbers of eggs laid and poor fertility of eggs. Local birds provide immense benefits for keepers but their productivity is significantly hindered by genetic and management problems. Study Two Another survey was conducted to evaluate the potential of indigenous naked neck (Nana) and frizzle (Ff) birds within the indigenous chicken population in the Ashanti Region of Ghana. The study involved ninety (90) interviewees who were local chicken keepers in Bosomtwe Atwima-Kwanwoma, Ejisu-Juaben and Asante-Akim South Districts. Average body weight of Nana cocks did not differ significantly (P>0.05) from Ff & nana/ff (normal feathered) ones while Nana hens were significantly (P>0.05) heavier than Ff birds, but nana/ff birds did not differ significantly (P>0.05) from the two genotypes. Nana layers were significantly superior (P<0.05) in egg size, number of eggs per clutch and number of eggs per bird per year to Ff layers which were significantly better than nana/ff layers. However, clutches of eggs per year did not show any significant difference (P>0.05) among the three genotypes. Eggs from Ff layers had a significantly higher (P<0.05) hatchability compared to those from Nana & nana/ff layers. Eggs from Nana layers were significantly better (P>0.05) in Haugh unit and egg shell thickness compared to those from Ff & nana/ff layers and eggs from Ff layers were significantly better (P>0.05) in Haugh unit compared to those from nana/ff layers. Mortality was significantly lower (P>0.05) in Nana birds followed by Ff & nana/ff birds respectively. The carcass of Nana birds had a significantly higher (P>0.05) dressing percentage than that of Ff and nana/ff birds. Naked neck and frizzle genes improve the productivity of local birds but the naked neck gene appears to be more effective than the frizzle gene. Study Three The first mating in Experiment Three was between four indigenous naked neck males and thirty-six Lohmann commercial females in a ratio of 1: 9. This produced offspring in the proportion of 48.7% Nana to 51.3% nana in the F1 generation. Nana birds were significantly better (P<0.05) in body weight, body weight gain, number of eggs per clutch, hen-housed and hen-day rates of lay, egg size, Haugh unit, shell thickness, survivability and carcass yield, than their nana counterparts. However, age at first egg and egg size to body weight ratio were significantly better in the nana birds compared to the Nana ones. In the second mating, ten males and one hundred females of F1 Nana birds were selected and mated inter se in a ratio of 1:10. This produced 16.8% NaNa, 54.5% Nana and 28.7% nana offspring in the F2 generation. It was observed that Nana and NaNa birds were significantly higher (P<0.05) in body weight, body weight gain, number of eggs per clutch, hen-housed and hen-day rates of lay, egg size, Haugh unit, shell thickness, survivability and carcass yield, compared to their nana counterparts. However, chick survivability was significantly better (P<0.05) in the nana birds compared to Nana and NaNa ones. Using birds that show the naked neck phenotype in local chicken production will enhance productive and reproductive performances significantly. Study Four Five local frizzle males were mated to forty Lohmann commercial females in a ratio of 1:8. This produced almost equal numbers of offspring, that is 50.2% Ff and 49.8% ff in the F1 generation. The Ff birds were significantly superior (P<0.05) to their ff counterparts in terms of body weight, number of eggs per clutch, hen-housed and hen- day rates of lay, Haugh unit and carcass yield. However, survivability was significantly better (P<0.05) in the ff birds compared to the Ff birds. The second mating was made between ten males and one-hundred females of F1 Ff birds. It was done inter se in a ratio of 1:10. This produced offspring in the proportion of 22.4% FF, 51.5% Ff and 26.1% ff in the F2 generation. The F2 Ff and FF birds were significantly higher (P<0.05) than their ff counterparts in number of eggs per clutch, hen-housed and hen-day rates of lay, Haugh unit, shell thickness, survivability and carcass yield. However, body weight, body weight gain, egg size and chick mortality did not differ significantly between the frizzles and the ff genotypes. Using frizzle (FF, Ff) hybrids in local chicken production will increase productivity markedly, though to a lesser extent than the naked necks (NaNa, Nana). Study Five In a comparative study involving all the five genotypes (NaNa, Nana, FF, Ff and nana/ff) reared under intensive, semi-intensive and extensive management systems, it was observed that the NaNa and Nana birds performed better (P<0.05) than their FF and Ff counterparts in body weight, body weight gain, number of eggs per clutch, hen- housed and hen-day rates of lay, egg size, Haugh unit, shell thickness, carcass yield and economics of production. It was also economically most profitable to rear all the genotypes (NaNa, Nana, FF, Ff & nana/ff) under the semi-intensive system followed by the extensive and the intensive systems respectively. Aside genetic improvements, rearing local birds under the semi-intensive system will improve profitability significantly.
Effect of decomposing crop residues on soil properties and crop productivity in the semi−deciduous forest zone of Ghana
(2009-08-09) Arthur, Alfred
A study was carried out to examine recycling of crop residues as a major component of integrated soil fertility management. The objectives of the study were to determine the quality, rates of decomposition and nutrient release patterns from residues of cassava leaves, cowpea haulm, groundnut haulm, maize stover, mucuna and soyabean haulm typical of cropping systems in Ghana as sources of plant nutrients. The study aimed at i). estimating the time course of nutrient release from crop residues to improve synchrony and increase maize yield, as well as ii). examining the changes in soil physico – chemical properties by applying some of the residues (maize stover and cowpea haulm) either alone or in combination with NPK (15–15–15) fertilizer. Laboratory and field experiments were conducted. The field experiments were conducted at the Central Agricultural Station, Kwadaso, Kumasi, in the semi – deciduous forest zone of Ghana. The laboratory experiments were conducted at the Soil Science laboratory, KNUST, Kumasi. The field studies were conducted on Asuansi soil series (Ferric Acrisol) in the minor season of year 2006 and repeated in the major and minor seasons of 2007. Total N content of the crop residues ranged from 0.74% in maize stover to 2.95% in cowpea haulm. Organic carbon ranged between 44.70% in groundnut haulm and 47.50% in maize stover. Total phosphorus ranged from 0.22% in groundnut haulm to 0.38% in maize stover. The C: N ratio of the residues ranged from 15.3 in mucuna to 65.1 in maize stover. In the major season, the decomposition rate constant (k) was 0.224 and 0.305 week-1 for surface – placed and buried maize stover respectively and 0.475 and 0.502 week-1 for cassava leaves. In the minor season, the k values were 0.210 and 0.240 week -1 for maize stover, 0.421 and 0.523 week-1 for cowpea haulm and 0.541 and 0.659 week-1 for cassava leaves. The values recorded in the dry season were 0.145 and 0.158 for maize stover, 0.206 and 0.258 for cowpea haulm and 0.233 and 0.290 for cassava leaves. Burying of the crop residues reduced the half – life (t50) from 4.37 to 3.88 weeks for maize stover, 3.07 to 2.77 weeks for cowpea haulm and 2.62 to 2.34 weeks for cassava leaves. Microbial biomass C and N were higher under the various treatments compared with microbial biomass P. Most of the microbial biomass P was locked up in the microbial cells. Combined application of the high quality cowpea haulm and low quality maize stover was able to increase the microbial biomass P. Mean grain yield was highest (1.69 t ha-1) under maize stover + ½ NPK treatment followed by cowpea haulm + ½ NPK treatment (1.62 t ha-1) with the control treatment recording the lowest (0.83 t ha-1). The results showed that all the treatments had significant effects on soil pH after cropping for three seasons. The level of organic matter increased under fertilizer treatment, while it decreased under the control treatment. Total N remained almost unchanged in all the plots after cropping. Available P decreased from initial value of 26.00 mg kg-1 to 25.09 mg kg-1 where no fertilizer was added but increased by 35 – 80% under fertilizer treatments. Exchangeable Ca, K and Na decreased in all the plots irrespective of the type of amendment. The combination of maize stover + ½ cowpea haulm increased the ECEC by 3%, remained unchanged under maize stover + ½ NPK treatment while it decreased in all other plots. Though maize grain yield increased under the combined application of crop residues and NPK fertilizer in this study, data on changes in soil properties after cropping suggest the need to increase the duration and the level of organic material added to sustain the fertility of the soil.
The Agronomic qualities of the Mexican Sunflower (Tithonia diversifolia) for soil fertility improvement in Ghana: an exploratory study
(2010) Partey, Samuel Tetteh
Soil fertility depletion remains a major biophysical constraint to increased food production in Ghana even when improved germplasm has been made available. With the growing concern of the potential of low input agriculture in mitigating soil fertility challenges, exploratory researches are imperative in selecting best quality organic materials that meet this expectation. This study was conducted to assess the suitability of Tithonia diversifolia green biomass as a nutrient source for smallholder agriculture in Ghana using both on-station and on-farm trials. The on-station research comprised an evaluation of the decomposition and nutrient release patterns of T. diversifolia in comparison with well-known leguminous species of agroforestry importance: Senna spectabilis, Gliricidia sepium, Leucaena leucocephala and Acacia auriculiformis. Concurrently, field trials were conducted to appraise the quality of T. diversifolia green biomass in relation to its biophysical effects on soil properties and the agronomic characteristics of crops. This was a comparative study with S. spectabilis, G. sepium and mineral fertilizer on a ferric acrisol. Field trials were also conducted to determine best practices for optimum biomass production of T. diversifolia using different pruning regimes and cutting heights as factors. The on-farm research was conducted at Dumasua in the Brong Ahafo Region of Ghana to appraise 200 farmers’ preliminary knowledge of T. diversifolia and evaluate the effect of T. diversifolia green biomass on soil fertility indicators and crop yields. The results of the decomposition study confirmed significantly high N, P, K concentrations in T. diversifolia comparable to levels recorded for the four leguminous species. In addition, T. diversifolia recorded the highest decomposition and nutrient release rates which differed significantly (p < 0.05) vii from rates of the four leguminous species. Although decomposition and nutrient release rates of species were related to quality of leaf material, P and Mg concentrations in particular were most influential in decomposition and nutrient release based on significant results. The on-station trials showed significant effect of the green manures (particularly T. diversifolia) on soil properties and the biomass and fruit yield of okro (Abelmoschus esculentus). These results were comparable and in some cases greater than fertilizer treatments. Total yield response in T. diversifolia treatment was 61% and 20% greater than the control and fertilizer treatments respectively. From the pruning experiment, it was evident that height of cutting, pruning frequency and their interaction significantly affected dry matter production of T. diversifolia. Dry matter production was highest (7.2 t ha-1yr-1) when T. diversifolia was pruned bi-monthly at 50 cm height. Results from the sociological survey confirmed farmers’ general knowledge on T. diversifolia at Dumasua was poor. Although majority of respondents had seen the plant growing, none could give a common name. Only the ornamental importance of T. diversifolia was identified. Meanwhile, the on-farm trials revealed a significant synergistic effect of combining T. diversifolia and fertilizer on soil nutrient availability and harvest index of maize. The results showed that the application of Tithonia either alone or in combination with fertilizer can increase yield by 24% and 54% respectively compared to plots which received no inputs.
The ecology and management of elephants (loxodonta africana matschie) in the bia – goaso forest enclave of western ghana
(2010-05-22) Sam, Moses Kofi
Elephants are important mega fauna whose role in an ecosystem could ensure the health and survival of diverse species. However, drastic declines in their numbers since the 19th Century in Africa in general and West Africa in particular has necessitated the need to understand their ecology in the local context to help improve their survival. This study was therefore conducted in the Bia-Goaso forest enclave in Ghana to contribute to the achievement of the objectives of the Elephant Conservation Strategy of Ghana (2000) and the “Action plan for the Management of the Transfrontier Elephant Conservation Corridor of Bia-Goaso-Djambarakrou,” which contain activities geared towards ensuring the survival of forest elephants in Ghana and West Africa respectively. In February 2004, a dry season survey on elephants and an investigation into the different levels of human and ecological variables that affect their abundance and distribution was conducted in an extensive network of eleven forest reserves and two wildlife reserves in the Bia–Goaso enclave of western Ghana. These activities were repeated twice, first in the rainy season of 2007 and the following dry season which started in 2007 and ended in 2008 mainly to understand seasonal effects in distribution of elephants in the area. During this period, the most up-to-date method for surveying forest elephants, the retrospective method was employed. A desk-top exercise was then undertaken not only to prove the importance or otherwise of the elephant populations in the study area in comparison with other elephant populations in West Africa but also to determine factors that govern their abundance. A preliminary investigation into the feasibility of creating corridors between reserves in the study area and neighbouring Ivory Coast was initiated in May 2004. As part of this, the movements of elephants from Ghana into Ivory Coast along the Bia river was monitored every quarter between August 2005 and December 2006, as well as an investigation into the rate of forest degradation. The nature and extent of human – elephant conflicts in the Bia Conservation Area was also studied through administration of questionnaires using interviews and field measurements. One hundred and thirty (130) transects were systematically distributed in three strata (high, medium and low density) based on dung pile density estimates in an initial reconnaissance. Two models (rainfall and steady state assumption models) were used to estimate elephant dung pile density and numbers in the study area. However, the rainfall model is preferred since it iii makes no assumption about the state of the forest. Two major elephant populations were observed to be residing in the study area, with the possibility of a tiny third population of less than 10 elephants (in the Bia North FR). In the 2004 survey, a mean population estimate of 115 (CL: 90 - 148) elephants was obtained for the Bia Resource Reserve. The eastern portion of the Mpameso Forest Reserve (medium density stratum) had an estimate of 57 (CL: 33 - 100) elephants. Elephant numbers could not be estimated for the rest of the reserves (low-density stratum) because of inadequate number of dung piles on transects. In the 2007/8 survey, estimates of 133 (CL: 104 - 162) elephants and 137 elephants (CL: 98 - 170) elephants were obtained for Bia CA during the dry and wet season surveys respectively. While for the Mpameso elephant range, estimates of 83 (CL: 41 - 125) elephants and 90 (CL: 49 - 131) elephants were obtained in the dry and wet seasons respectively. Merged estimates for both seasons were 135 (CL: 114 - 156) elephants for Bia and 87 (CL: 58 - 116) elephants for Mpameso. Altogether, a total population of 172 (CL: 123-264) elephants were estimated to be occurring in the entire study area. Elephants were found to be clumped more to the southeast of BRR, the eastern part of Mpameso and the Bia Shelterbelt FR. Elephants were found to be more widely spread out in the wet season than in the dry season within BCA. Analysis of dung pile distribution in relation with human and ecological variables in both the 2004 and 2007/8 studies showed that within the reserves, water availability explained a high proportion (ca. 90%) of the variance in elephant density, with elephants being clumped around watering points created as a result of logging. Additionally, in 2004, distance to the Bia River was inversely correlated to the number of dung piles seen per km in the Mpameso Forest Reserve. Illegal activities (such as snaring and snail picking), however, did not affect elephant abundance but rather had a negative correlation with watering points, that is, they were undertaken away from these watering points. This suggests that poachers were avoiding areas of high water availability, possibly because of high elephant activity around those areas. Outside reserves, the distance to major towns and roads accounted largely for variances in elephant density in 2004. In 2007/8 on the other hand, logging roads and availability of raphia also entered the model as significant variables, though they did not add much power to the models. By all standards, the Bia population on its own is a very important one in the sub-region. The Goaso population is smaller. However, the security of its range, and the possibility of linking it with others makes it also even iv more important for the overall conservation of forest elephants in West Africa. It was established during the study that elephant abundance in West Africa depends on the size of a population‟s range, to whether the range is protected, its geology and the quality of governance in the country where it occurs. Elephant crop damage is a serious problem in the area, especially to cluster of farms that border the southern portions of the Bia Resource Reserve, resulting in conflicts between farmers and nature conservation. Food crops such as plantain, cassava, cocoa and maize suffered severest damage. These are most preferred by the elephants when in the matured state and the quality is excellent. For each community, that suffered crop-raiding, the extent of crop-raiding depended not only on the area of land under cultivation but also the mean distance of farms from the reserve boundary, as well as the number of different crops planted on the farm. Interviews conducted in 2004 indicated that most migrant farmers do not see any advantage in preserving elephants and would do little to conserve them. While they were not willing to sacrifice part of their already overburdened farmlands for establishing elephant corridors, they also feared a possible increase in human-elephant conflicts in the future. However, most villages adjacent to streams/rivers showed a strong interest in restoring the riparian forest since they faced water and fish shortages in the dry season. More lately, there have been several forest restorative activities going on in the study area in the hope of returning wildlife into communal lands. Hence, there has been a generally increasing level of awareness concerning the conservation and protection of lands to serve as corridors. Of six potential corridors considered, one along the Bia river linking the Goaso population to those in Ivory Coast and from Bia Resource Reserve to Krokosue Hills Forest Reserve have the greatest potential in the short to medium term, and it is also likely that with a high level of interventions, two others could be achieved over the long term. A more detailed spatial analysis in combination with ground truthing is required before a conclusive decision on viable corridors can be made. Also a more participatory information gathering strategy (such as Timelines, H-Diagram) for soliciting community opinions on corridors have been suggested to complement the use of questionnaires. Recommendations also include a detailed study of elephant movements in the Ivorian side of the corridor.
Evaluation of productive Performance of Crossbred Naked-Neck and Frizzle Chicken Genotypes
(2010-07-13) Hagan, Julius Kofi
Two studies (survey and experimental work) were conducted to determine the frequency and incidence of naked-neck and frizzle genes existing in the indigenous chicken and to evaluate the performance of crossbred naked-neck and frizzle birds. In the first phase of the work a survey covering a three month period was conducted in six randomly selected districts in the Ashanti Region of Ghana. From the survey it was observed that the heat-tolerant genes, though dominant in nature, had very low frequencies of 0.03 and 0.05 for frizzle and naked-neck respectively. With regard to the experimental work, two studies (on-station and on-farm) were carried out to evaluate the egg production, growth and carcass characteristics of four crossbred naked-neck and frizzle genotypes, namely: (i) Na/naF/f, (ii) Na/naf/f (iii) na/naF/f and (iv) na/naf/f. These crossbred cockerels were generated from a reciprocal crossing between crossbred heterozygous naked-neck (50% indigenous naked-neck and 50% Lohman Brown) and frizzle (50% indigenous frizzle and 50% Lohman Brown) stocks. In the first on-station experimental study, one hundred and twenty (120), nine-week old crossbred cockerels (thirty each of the four genotypic groups) were randomly assigned to nine deep litter pens in a Completely Randomized Design for six weeks and their growth and carcass characteristics evaluated. The birds were provided with grower mash ad lib throughout the experimental period. At the end of the six-week trial, 3 cockerels from each of the four genotypic groups were randomly selected and slaughtered and their carcass parameters determined. The results indicated that there was no significant phenotype effect on initial body weights. iv However, the naked-neck frizzle phenotypes were significantly heavier at 14 weeks than the other phenotypes. The double heterozygous cockerels also gained significantly more weights than the other genotypes. The double heterozygous frizzled naked-necks (Na/naF/f) consumed significantly (P<0.05) more feed than the single heterozygous frizzles and naked necks (Na/na and F/f) and the normally feathered birds (na/naf/f). The double heterozygotes were significantly better converters of feed into meat than their single heterozygote and normally feathered counterparts. With respect to carcass yield characteristics, the double heterozygous cockerels had significantly (P<0.05) higher values in terms of percent leg yield, breast yield, thigh yield, dressed weight and dressing percentage. The second part of the on-station experimental work involved one hundred and twenty (120), eighteen-week old crossbred pullets (thirty each of the four genotypes) which were randomly assigned to a CRD experiment for a period of up to 60 weeks. The selected pullets were put in a partitioned deep-litter house, with 10 pullets in each compartment and provided with layer mash ad lib throughout the experimental period. The double and the single heterozygous pullets laid their first egg significantly (P<0.05) earlier than their fully feathered counterparts. The double heterozygotes produced significantly (P<0.05) more eggs (130) than the single heterozygotes (121 and 122) which also produced significantly more eggs than the normally feathered birds (113). Feed was more efficiently converted into eggs by the double heterozygous pullets than the other genotypes. There were no significant (P>0.05) differences among the genotypes in terms of eggshell thickness, albumen height, yolk height, Haugh unit and yolk v colour. Another on-farm study was carried out to compare egg production performance of the crossbred naked-neck and frizzle pullets and normally feathered local pullets under the semi-scavenging system. In this trial, 240, 10-week old randomly selected crossbred pullets (eighty each of naked-neck frizzle, naked-neck only and frizzle only) were distributed to some 10 selected farmers in the Ashanti Region of Ghana. The crossbred double and single heterozygous pullets were reared alongside the farmers’ own normally feathered local pullets that were of the same age as the crossbred pullets. Results on total eggs laid up to 60 weeks of age showed the crossbred pullets laying significantly (P<0.05) more eggs (105 eggs) than the local hens (78 eggs). There was a significant difference (P<0.05) between the crossbred pullets (181 days) and the local pullets (217 days) with respect to age at first lay. The crossbred layers produced eggs at a significantly (P<0.05) higher rate (43%) than the local layers (37%). Eggs laid by the crossbred layers were significantly (P<0.05) bigger than those laid by the local hens throughout the entire laying period. The farmers’ local pullets recorded significantly (P<0.05) lower deaths than the crossbred pullets, but between the crossbreed pullets (double and single heterozygotes), there were no significant differences. There was a genotype-environment interaction for rate of lay and mortality for the crossbred naked-neck and frizzle genotypes when the performance of the birds was compared under on-station and on-farm conditions. Estimates of heterosis showed that F2 offspring from the F X Na reciprocal cross were better than the offspring from the Na X F main cross in terms of body weights, egg weight and egg production parameters measured.

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