Department of Nuclear Agriculture and Radiation Processing
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Item On Farm And Post-Harvest Management Of Mango Stone Weevil (Sternochetus mangiferae F.)(University Of Ghana, 2022-05) Aboagye, E.N.G.A questionnaire composed of twenty-three (23) open and closed-ended questions was administered to thirty (30) mango farmers within the eastern mango enclave to investigate the level of mango stone weevil (MSW) infestation within the eastern mango enclave. Data obtained from the questionnaire was analysed using the SPSS version 25.0 and presented as tables in percentages. Chi-square was used to determine the association between selected parameters. The response from farmers revealed that 40.7% of farmers grow only one variety of mango and the common variety is Keitt which is cultivated by 33.7% of the farmers. About eighty-seven percent of the farmers admitted to the presence of the mango stone weevil on their farms. Fifty percent of the farmers were found to be relying on insecticides for controlling the MSW. About seventy-seven percent of the respondents viewed the mango stone weevil as a major pest because it is a pest of phytosanitary importance. The major mango season was considered to have the highest infestation as indicated by 90% of respondents. Responses from farmers revealed that 76.7% spend about GH¢2000:00 – 5000:00 per acre every season in controlling the mango stone weevil. A survey was conducted during the major and minor mango seasons immediately after the questionnaire administration. During the survey, thirty (30) farms were visited. On each farm, fifty (50) matured fruits were randomly picked and dissected to check whether the seeds are infested or free from weevils. The survey brought to light that, the MSW is at its highest level during the major season as compared to the minor season. Infestation levels on the average were 23.6% and 19.13% for the major and minor seasons respectively. To determine the effect of trunk banding using a sticky band, grease and insecticide in the control of MSW, the sticky band proved to be the most efficient method. The sticky band had lower fruit infestation levels (i.e., 11.5% for minor mango season and 10.5% for the major mango season) which were significantly different from the fruit infestation levels of the grease banding for both minor and major seasons. Although an X-ray imaging technique could not capture the image of mango stone weevil within infested fruits, it was able to capture the image of damaged cotyledon which resulted from feeding by mango stone weevils. The findings of the research showed that the mango stone weevil is persistent in the study area, mango stone weevil infestation levels are high during the major mango season, the sticky band is more effective in controlling the mango stone weevil and lastly soft X-ray technique can be used to detect internal infestation of mango by the stone weevil. These findings would go a long way to address the menace of MSW infestation, the efficient and effective method of controlling mango stone weevil and a non-destructive method of detecting MSW infestations which would improve the fortunes of Ghana in the export of fresh mango fruits.Item Effect Of Gamma Irradiation On Propagation And Creation Of Variability In Caesalpinia Pulcherrima L And Canna Indica L(University Of Ghana, 2022-10) Owusu, E.Item Mutagenesis Of Cowpea for Early Maturity and Higher Yield(University of Ghana, 2020-10) Dorvlo, I.KABSTRACT Cowpea [Vigna unguiculata (L.) Walp.] is an important grain legume that is widely grown in sub-Saharan Africa (SSA) for food and feed. Its grain is composed of high levels of protein, carbohydrate, micro-nutrients and macro-nutrients which are essential for human nutrition. In Ghana, cowpea productivity is considerably low due to frequent terminal drought as a result of climatic changes. Therefore, breeding improved varieties by incorporating “farmer-preferred” traits remains an overriding consideration to boost the productivity of cowpea in Ghana. The main objective of this study was to develop early maturing and high seed yielding cowpea varieties through mutation induction using gamma irradiation. Before the commencement of the mutagenesis, it is important to determine the right dose of gamma radiation for causing genetic variability in the desired agro-economic trait. Therefore, seeds of a farmer-preferred cowpea variety ‘Videza’ (obtained from a farmer in Akatsi, Volta region of Ghana) were gamma irradiated using twelve irradiation doses (0, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000 and1100 Gy) at GAEC. Using a linear regression model, the LD50 value of the cowpea variety ‘Videza’ was calculated as 240.51Gy. A dose-dependent reduction was observed in seed germinastion, seedling survival and plant height. For mutation induction, 2000 seeds of cowpea variety ‘Videza’ were acutely irradiated at 230 Gy, at the Radiation Technology Centre (RTC) of Ghana Atomic Energy Commission (GAEC), Accra, Ghana, using a Cobalt 60 source, delivering at a dose rate of 300 Gy/hr. Normal looking M1 plants with the desired traits (early maturity and high seed yield) were advanced to M2 generation and further advanced to M3 generation. The planting was linear and serpentine at a seeding rate of one seed per hill using 75cm x 40 cm. Control seeds were sown in three rows after every ten rows of the irradiated seeds separated by a spacing of 1.50m. Compared to the Control (Videza), genetic variability was recorded among plants in both M2 and M3 generation. The extent of genetic variability for the number of days to 50% flowering, number of days to 90% maturity, number of pod-bearing branches per plant, number of pods per plant, number of seeds per pod, 100-seed weight (g) and seed yield per plant (g) were evaluated in M2 and M3 generations. The number of days to 50% flowering and 90% maturity reduced in putative mutants in both M2 and M3 generations compared to the parental line (Control). The number of days to 50% flowering and days to 90% maturity, reduced further in the M3 generation as compared to M2. Increments in 100-seed weight per plant (g) and seed yield per plant (g) were observed among the putative mutants in M3 generation compared to the parental line (Control). The following twelve putative mutant lines P1N06#20, P1N06#9, P1N08#13, P1N08#17, P2N09#12, P4N03#2, P4N14#7, P5N05#10, P5N07#14 and P6N10#19 were outstanding in the M3 generation, exhibiting both early maturity as well as high seed yield. The twelve putative mutant lines are recommended for yield trials (preliminary and advanced), alongside the parental line (Videza) as well as a local check (as Controls), in farmer-participatory multilocational trials (including the Akatsi District of the Volta Region of Ghana) towards identifying superior lines for release as new variety or varieties.Item Biopesticide Control of Some Important Okra (Abelmoschus Esculentus (L.) Moench) Insect-Pests and Viral Diseases in Three Okra Cultivars(University of Ghana, 2020-10) Akama, C.K.A.The production, processing and marketing of Okra (Abelmoschus esculentus L. Moench), a vegetable valued for its rich nutritional and medicinal benefits, serves as an important means of employment and income generation to many peasant farmers. The production of the crop is, however, constrained by the incidence of pests (whitefly and flea beetle) and okra yellow vein mosaic virus [OYMV] and okra mosaic virus [OMV]) diseases. To overcome the health and environmental risks associated with the excessive use of synthetic agrochemicals, the predominant means of control of these pests and viral diseases, the efficacy of crude leaf extracts as biopesticides from Neem, Jathropha and Lemon grass on the incidence and severity of OMV and OYVMV as well as crop damage due to whitefly and flea beetle, were evaluated in three okra cultivars [F1 Kirene (F1K), FI Sahari (F1S) and Asontem (AST)]. Among the three plant extracts tested, Neem extract treatment induced significantly (p<0.05) the lowest mean count of whitefly [ASTNEM (18.91), F1KNEM (22.17), F1SNEM (24.49)] compared to Jathropha extracts [ASTJAT (27.99), F1KJAT (28.73), F1SJAT (28.74)] and Lemon grass extract treatments [ASTLEM (34.22), F1KLEM (32.77), F1SLEM (32.67)]. Similar results were obtained for mean population of flea beetle. With respect to insect pests damage to the okra cultivars, Neem extract caused significantly (p<0.05) the lowest severity of damage [F1KNEM (1.53), F1SNEM (1.58), ASTNEM (1.63)] compared to Jathropha extract treatment [F1SJAT (2.74), ASTJAT (2.75), F1KJAT (2.77)] and Lemon grass extract [F1SLEM (2.97), ASTLEM (3.64), F1KLEM (3.73)]. Similarly, the application of Neem extract significantly (p<0.05) reduced the mean incidence (21.84%) of the viral diseases than Lemon grass extract (25.28%), Jathropha extract (25.44%) and the Control (28.89%). In-vitro confirmation test using Enzyme-linked immunosorbent assay (ELISA) revealed that majority (86.67%) of the treatment combinations showed single infection of OMV disease while in 13.33% of the treatment combinations mixed-infection of OMV and OYVMV diseases was observed. In terms of yield levels, chemical pesticide treatment produced significantly (p<0.05) highest yield (186.92 kg/ha) compared to Neem extract treatment (144.81 kg/ha), Jathropha extract (139.06 kg/ha), Lemon grass extract (115.75 kg/ha) and the Control (94.02 kg/ha). However, Neem extract performed best among the tested plant extracts. Therefore, in a second experimental trial to ascertain the best efficacious dose for Neem extract application, varying concentrations of 20 ml/L, 30 ml/L and 40 ml/L were used and compared with the chemical “Akape” in the three okra cultivars (F1K, F1S and AST) instead of the 50ml/L applied in the first experimental trial. Treatment with “Akape” recorded significantly (p<0.05) the lowest mean whitefly populations than treatment with plant extracts. However, 20 ml/L Neem extract treatment produced significantly (p<0.05) lowest mean count of whitefly [F1KN1 (17.88), ASTN1 (23.95), F1SN1 (29.01)] compared to 40 ml/L Neem extract [F1KN3 (37.90), ASTN3 (39.57), F1SN3 (38.22)]. Similarly, although the application of the synthetic chemical (insecticide) “Akape” resulted in the best performance in reducing flea beetle populations, it was observed among the Neem extract concentrations, 20 ml/L treatment produced significantly (p < 0.05) lowest flea beetle mean count [F1KN1 (24.04), ASTN1 (25.61), F1SN1 (29.41)] compared to 30 ml/L [F1KN2 (49.89), ASTN2 (48.73), F1SN2 (51.92)] and 40 ml/L [F1KN3 (72.68), ASTN3 (65.88), F1SN3 (80.88)] treated okra cultivars. Okra cultivars treated with 20 ml/L Neem extract had significantly (p<0.05) lowest severity of insect pest damage compared to treatment with 40 ml/L Neem extract. Of the three concentrations of Neem extract applied, 20 ml/L (N1) significantly (p<0.05) reduced severity of mixed-infection of OMV and OYVMV) in all the three okra cultivars [ASTN1 (0.64), F1KN1 (0.84), F1SN1 (1.23)]. Yield of okra cultivars treated with chemical pesticide was significantly (p>0.05) highest (234kg/ha). However, yield obtained with 20 ml/L Neem extract treatment (207kg/ha) was significantly (p>0.05) highest compared to the other Neem extract doses. It is noteworthy that cultivar F1 Kirene recorded significant (p<0.05) the highest yield (207kg/ha) followed by F1 Sahari (139kg/ha) and Asontem (127kg/ha). From the obtained results, the cultivation of the okra cultivar F1 Kirene could be combined with Neem extract at a concentration of 20 ml/L to obtain effective disease and pests control for high yields.Item Radiation Preservation of Black Velvet Tamarind (Dialium guineense Wild.)(University of Ghana, 2010-12) Ofosu, D. O.The economic distribution and marketing of the lesser known fruit Dialium guineense Wild in Ghana has been studied using a structured questionnaire and the rapid appraisal system. The seasonality of the fruit (from January to May) makes it abundant in the peak season and rare or not all for the best part of the year. Some fruits also go to waste in the field owing to underexploitation. This thesis provides information on the resident fungi, mycological quality, sorption isotherm, and the effect of gamma irradiation and packaging on the physico-chemical properties of the fruit and the sensory evaluation of the pulp by a taste panel with the view to showing the economical and nutritional potential of the fruit. The resident fungi and mycological quality were assessed by the conventional decimal serial dilution technique and plating on three media (PDA, DG 18 and OGYE). Sorption isotherms at 29±J -c were determined under simulated Environmental Relative Humidity (20, 55, 65, 75, 85, 95%) provided by glycerol: water mixtures; physico-chemical properties were assessed by the method of the Association of Official Analytical Chemists. Descriptive and preference sensory evaluation were administered using prescribed international methods on a hedonic scale. The tamarind markets are in the southern sector of the country, namely Greater Accra, Eastern, Central, Ashanti and Volta Regions with the hub at Ho, Abor and Akatsi in the Volta Region. The local names of the fruit varied from one region to another. The fruit was purchased mostly by adult females (48.25%) followed by school children (37.06%) and adult males (14.68%). The produce is marketed predominantly in polypropylene sacks (81.81 %) with jute sack taking only 3.63% of the packaging. The sizes of the fruit as expected were variable. The pulp did not lose moisture at 75% ERH but lost moisture to the surrounding at ERI-I's 20, 55, and 65% and the same was true for the whole (intact) fruit. The resident fungi in the pulp belonged to 15 fungal species and 7 genera (Aspergillus, Candida, Cladosporium, Fusarium, Penicillium, Neurospora and Rhodotorula). The fungal flora was predominated by Aspergillus (A. alutaceus, A. candidus, A. flavus, A. fum igat us, A. niger, A. sulphureus, A. ustus) followed by Penicillium (P. digitatum, P. expansum) all of which are being recorded for the first time in the fruit of D. guineense. The fruits were also infested with an insect, Ephestia cautella, of economic importance. There was a commensurate drastic reduction in the mould count in the fruit as the irradiation dose increased from 0 to 10kGy. The resident fungi were not however completely eliminated with the variable residual species appearing after 3 months storage in the packaging materials (polypropylene, polyethylene and jute). The presence and isolation of mycotoxinproducing species A. flavus (Aflatoxins), A. alutaceus (Ochratoxins), P. expansum, P. digitatum (Patulin), F verticilloides (fumonisin) leave much to be desired. Packaging did not significantly influence pH and ash content; but influenced total titratable acidity with increasing dose and storage time. The crude fat content decreased with prolonged storage and increasing dose of gamma irradiation while there was no interaction between dose applied, packaging material and storage time. The panelists did not find significant (P>0.05) difference in the parameters tested for acceptance (colour, sweetness, acidity and tenderness) and they found no differences in the packaging material although they slightly preferred produce kept in jute sacks. The practical implications of these findings are discussed in the light of future promotion and preservation of the pulp for industrial use after gamma irradiation.Item Radiation Preservation of Black Velvet Tamarind (Dialium guineense Wild.)(University of Ghana, 2010-12) Ofosu, D.O.The economic distribution and marketing of the lesser known fruit Dialium guineense Wild in Ghana has been studied using a structured questionnaire and the rapid appraisal system. The seasonality of the fruit (from January to May) makes it abundant in the peak season and rare or not all for the best part of the year. Some fruits also go to waste in the field owing to underexploitation. This thesis provides information on the resident fungi, mycological quality, sorption isotherm, and the e ffect 0 f gamma irrad iation and packaging on the phys ico-chem ical properties of the fruit and the sensory evaluation of the pulp by a taste panel with the view to showing the economical and nutritional potential of the fruit. The resident fungi and mycological quality were assessed by the conventional decimal serial dilution technique and plating on three media (PDA, DG 18 and OGYE). Sorption isotherms at 29±J -c were determined under simulated Environmental Relative Humidity (20, 55, 65, 75, 85, 95%) provided by glycerol: water mixtures; physico-chemical properties were assessed by the method of the Association of Official Analytical Chemists. Descriptive and preference sensory eval uation were adrn inistered using prescribed international methods on a hedonic scale. The tamarind markets are in the southern sector of the country, namely Greater Accra, Eastern, Central, Ashanti and Volta Regions with the hub at Ho, Abor and Akatsi in the Volta Region. The local names of the fruit varied from one region to another. The fruit was purchased mostly by adult females (48.25%) followed by school children (37.06%) and adult males (14.68%). The produce is marketed predominantly in polypropylene sacks (81.81 %) with jute sack taking only 3.63% of the packaging. The sizes of the fruit as expected were variable. The pulp did not lose moisture at 75% ERH but lost moisture to the surrounding at ERI-I's 20, 55, and 65% and the same was true for the whole (intact) fruit. The resident fungi in the pulp belonged to 15 fungal species and 7 genera (Aspergillus, Candida, Cladosporium, Fusarium, Penicillium, Neurospora and Rhodotorulai. The fungal flora was predominated by Aspergillus (A. alutaceus, A. candidus, /I. flavus, A. fum igat us, A. niger, A. sulphureus, A. us/us) followed by Penicillium (P. digitatum, P. expansum) all of which are being recorded for the first time in the fruit of D. guineense. The fruits were also infested with an insect, Ephestia cautella, of economic importance. There was a commensurate drastic reduction in the mould count in the fruit as the irradiation dose increased from 0 to IOkGy. The resident fungi were not however completely eliminated with the variable residual species appearing after 3 months storage in the packaging materials (polypropylene, polyethylene and jute). The presence and isolation of mycotoxinproducing species A. flavus (Aflatoxins), A. alutaceus (Ochratoxins), P. expansum, P. digitatum (Patulin), F verticil/oides (fumonisin) leave much to be desired. Packaging did not significantly influence pH and ash content; but influenced total titratable acidity with increasing dose and storage time. The crude fat content decreased with prolonged storage and increasing dose of gamma irradiation while there was no interaction between dose applied, packaging material and storage time. The panelists did not find significant (P>0.05) difference in the parameters tested for acceptance (colour, sweetness, acidity and tenderness) and they found no differences in the packaging material although they slightly preferred produce kept in jute sacks. The practical implications of these findings are discussed in the light of future promotion and preservation of the pulp for industrial use after gamma irradiation.Item Nodulation, Nitrogen Fixation and Biomass Yield of Selected Forage Legume Species in Coastal Savannah Zone of Ghana(University of Ghana, 2017-07) Dien, M.K.Two field experiments were carried out in the major and minor rainy seasons at the BNARI research farm at Kwabenya, Accra, Ghana from July – November, 2016 to investigate nodulation, biomass yield and nitrogen fixation potential of ten forage legumes (Macroptilium atropurpureum, Stylosanthes guianensis, Crotalaria ochroleuca, Pueraria phaseoloides, Centrosema pubescens, Calopogonuim mucunoides, Cajanus cajan, Flemingia macrophylla, Lablab purpurus and Desmodium distortum). Completely randomized block design (RCBD) with four replications of each of the above named forage legumes was used. Sampling was done at eight weeks after planting for all the legume plants for both major and minor rainy seasons. Sub – samples of both maize and legume species for both major and minor rainy seasons were oven dried at 65oc for 72hrs, milled to fine powder and per cent total N analyzed using Kjeldahl Digestion Method at ECO LAB, University of Ghana, Legon. Nitrogen content for each sample was calculated using the per cent N analyzed and nitrogen difference method used in determining the N-fixed by the legume species. Nodules harvested from sampled plants were washed, moped, weighed for both fresh and dry nodule weight, counted for nodule number and sliced for nodule effectiveness for both major and minor rainy seasons. Data collected was subjected to analysis of variance (ANOVA) of RCBD using GENSTAT statistical package version 16 edition and Duncan’s Multiple Range Test (DMRT) used to separate means where significant differences were observed. On the whole, Crotalaria ochroleuca, C. cajan, L. purpureus, D. distortum and M. atropurpureum produced high dry matter yields. However, the highest (6817kg ha-1) and lowest (1747 kg ha-1) mean shoot dry matter yield for the major rainy season was produced by L. purpureus and S. guianensis respectively. The highest mean dry matter yield for the minor rainy season was 255.30 kg ha-1 for C. ochroleuca while the lowest was 110.30 kg ha-1 for C. pubescens. The highest mean total N yield being 144.50 kg N ha-1 was produced by L. purpureus and 47.70 kg N ha-1 being the lowest value was obtained by S. guianensis during the major rainy season. Crotalaria ochroleuca produced the highest N yield with the value 77.96 kg N ha-1 while the lowest N yield of 38.37 kg N ha-1 was produced by C. pubescens during the minor rainy season. The highest and lowest mean number of nodules produced per plant for the major rainy season were 266.50 for C. cajan and 16.5 for C. mucunoides respectively while the highest and lowest mean number of nodules for the minor season were produced by L. purpureus (153.5) and C. pubescens (3.75) respectively. However, the highest and lowest mean effective number of nodules for the major rainy season were produced by C. cajan (238) and C. mucunoides (10) respectively while the highest and lowest values for the minor season were 139 and 2 for L. purpureus and C. pubescens respectively. Cajanus cajan had the highest mean effective nodules (237.75) and F. macrophylla produced the lowest (10.25) effective nodules (EN) for the major season while in the minor season, L. purpureus had the highest EN (139) with C. pubescens having the lowest EN (3.75). The highest total nitrogen derived from atmosphere (Ndfa) for major rainy season was 112.45 kg N ha-1 for L. purpureus and the lowest total Ndfa of 15.64 kg N ha-1 was produced by S. guianensis. The legume species, C. ochroleuca had the highest Ndfa of 52.93 kg N ha-1 whiles C. pubescens produced the lowest Ndfa of 13.35 kg N ha-1 for the minor rainy season. Statistical analysis indicated highly significant (p ≤ 0.001) seasonal effect on most of the parameters measured for the forage legume species except root dry matter and N yields that had non- significant (p ≥ 0.05) seasonal effect. In conclusion, the linear regression between dry weight of effective nodules and Ndfa for each season, showed positive relationship with R2 values of 0.5807 and 0.4513 respectively, implying that increasing dry weight of effective nodules results in increasing NdfaItem Decomposition and Mineralization of Some Organic Residues in Two Contrasting Agro-Ecological Zones(University of Ghana, 2017-07) Tetteh, D.M.Decomposition and mineralization from plant and animal residues are important processes that can improve soil fertility and build–up soil organic matter. Decomposition and mineralization of 5 and 10 t/ha of matured cow dung (CD) in Ada soil series of the coastal savannah agro-ecological zone, as well as 5 and 10 t/ha of artisanal empty fruit bunch (EFB-AT) and industrial empty fruit bunch (EFB-IN) in Kokofu soil series of the semi-deciduous forest agro-ecological zone were studied using pots. The objective of the study was to assess the decomposition and nutrient release patterns of manured CD and EFB-AT and EFB-IN in order to give an estimate of the release patterns and to synchronize the nutrient release to meet the nutrient demands of crops. The study was conducted between February and June 2017. The dry CD at the two application rates were used for the study in Ada soil series, classified as Entisols (USDA classification) by Brammer (1960), which corresponds to Fluvisols under FAO (1970) classification. Also dry EFBs were used for the Kokofu soil series which are classified Ultisols USDA (Brammer, 1960). Dry CD was put in nylon litter bags, and was buried at 8 cm deep in the soil (in the pots) as practised by farmers in the Sege area, where CD is incorporated into the soil on application. Chopped EFBs of 2cm mesh size were put in nylon litter bags, and placed on the surface of soil in the pots as practised by farmers in the Kade area, where EFBs are placed on the soil surface in most oil palm plantations to serve as mulch. The EFB samples were taken from artisanal palm oil producers (EFB-AT) and industrial palm oil producers (EFB-IN). Buried CDs in pots were sampled at 7, 14, 21, 35, 56, 72 and 90 days whiles EFB-AT AND EFB-IN were sampled 7, 14, 21, 35, 56, 72 90,120 and 150 days after being placed on soil surface in pots. Sixty percent (60%) of the initial weight of the CD decomposed within 90 days with no significant difference (t=0.05) in the fractions lost between 5 and 10t/ha by t- test analysis, based on pair comparison. In the case of EFB-AT, about 20% of the 5 t/ha and 50% of 10 t/ha, of the initial weight had decomposed over the 150 days period. For EFB-IN about 78% of the 5 t/ha and 75% of the 10t/ha of the initial weight decomposed over the 150 days period. Comparatively, a t-test analysis, based on pair comparison, showed a significant difference (t=0.08) between the fractions lost by EFB-AT and EFB-IN at the two application levels. The estimated half-life (t ½) for the decomposition of CD were 82 and 99 days for 5 t/ha and 10 t/ha, respectively. For EFB-AT, the estimated half-life were 112 and 130 days for 5 and 10 t/ha, respectively, while for EFB/IN half-life was 83 and 87 days for 5 and 10 t/ha, respectively. Approximately between 10 and 20% of the initial TN content of the CD was released during the 90 days period with significant difference (t=0.07) in the fractions released between 5 and 10t/ha of CD. Similarly, approximately 15-20% of the initial TN of the EFB-AT and between 30 and 38 % of TN in EFB-IN was released during the 150 days period. Based on pair comparison, the difference in the TN released between EFB-AT and EFB-IN was significant (t=0.07) even between the two application rates (5 and10t/ha). Between 30-38% of the initial P content of the CDs was released while about 60% of the EFBs was released with significant difference (t=0.06) in the fractions released between 5 and 10t/ha, and between EFB-AT and EFB-IN. About 90% of the initial K content in EFBs was released while about 40-50% of the initial K content of the CDs was released during the experimental period, with significant difference (t=0.07) in the fractions of K released between 5 and 10t/ha CD and between EFB-AT and EFB-IN.Item Radiation Preservation of Black Velvet Tamarind (Dialium guineense Wild.)(University of Ghana, 2010-12) Odamtten, G.T.The economic distribution and marketing of the lesser known fruit Dialium guineense Wild in Ghana has been studied using a structured questionnaire and the rapid appraisal system. The seasonality of the fruit (from January to May) makes it abundant in the peak season and rare or not all for the best part of the year. Some fruits also go to waste in the field owing to underexploitation. This thesis provides information on the resident fungi, mycological quality, sorption isotherm, and the e ffect 0 f gamma irrad iation and packaging on the phys ico-chem ical properties of the fruit and the sensory evaluation of the pulp by a taste panel with the view to showing the economical and nutritional potential of the fruit. The resident fungi and mycological quality were assessed by the conventional decimal serial dilution technique and plating on three media (PDA, DG 18 and OGYE). Sorption isotherms at 29±J -c were determined under simulated Environmental Relative Humidity (20, 55, 65, 75, 85, 95%) provided by glycerol: water mixtures; physico-chemical properties were assessed by the method of the Association of Official Analytical Chemists. Descriptive and preference sensory eval uation were adrn inistered using prescribed international methods on a hedonic scale. The tamarind markets are in the southern sector of the country, namely Greater Accra, Eastern, Central, Ashanti and Volta Regions with the hub at Ho, Abor and Akatsi in the Volta Region. The local names of the fruit varied from one region to another. The fruit was purchased mostly by adult females (48.25%) followed by school children (37.06%) and adult males (14.68%). The produce is marketed predominantly in polypropylene sacks (81.81 %) with jute sack taking only 3.63% of the packaging. XIV xv The sizes of the fruit as expected were variable. The pulp did not lose moisture at 75% ERH but lost moisture to the surrounding at ERI-I's 20, 55, and 65% and the same was true for the whole (intact) fruit. The resident fungi in the pulp belonged to 15 fungal species and 7 genera (Aspergillus, Candida, Cladosporium, Fusarium, Penicillium, Neurospora and Rhodotorulai. The fungal flora was predominated by Aspergillus (A. alutaceus, A. candidus, /I. flavus, A. fum igat us, A. niger, A. sulphureus, A. us/us) followed by Penicillium (P. digitatum, P. expansum) all of which are being recorded for the first time in the fruit of D. guineense. The fruits were also infested with an insect, Ephestia cautella, of economic importance. There was a commensurate drastic reduction in the mould count in the fruit as the irradiation dose increased from 0 to IOkGy. The resident fungi were not however completely eliminated with the variable residual species appearing after 3 months storage in the packaging materials (polypropylene, polyethylene and jute). The presence and isolation of mycotoxinproducing species A. flavus (Aflatoxins), A. alutaceus (Ochratoxins), P. expansum, P. digitatum (Patulin), F verticil/oides (fumonisin) leave much to be desired. Packaging did not significantly influence pH and ash content; but influenced total titratable acidity with increasing dose and storage time. The crude fat content decreased with prolonged storage and increasing dose of gamma irradiation while there was no interaction between dose applied, packaging material and storage time. The panelists did not find significant (P>0.05) difference in the parameters tested for acceptance (colour, sweetness, acidity and tenderness) and they found no differences in the packaging material although they slightly preferred produce kept in jute sacks. The practical implications of these findings are discussed in the light of future promotion and preservation of the pulp for industrial use after gamma irradiation.Item Studies Of Essential And Non-Essential Elements In Cereal-Based Weaning Foods For Infants Commercially Available On The Ghanaian Market(University of Ghana, 2013-07) Bawol, S.Cereal-based weaning foods, which abound on the Ghanaian market, are nutritionally vital in the growth and development of infants. Recent reports in scientific literature however indicate that rice and other cereals used in the manufacture of the weaning foods contribute significantly to the intake of arsenic (As), cadmium (Cd) and lead (Pb) by infants. In view of this, frequent monitoring of the cereal-based weaning foods has become imperative. The study assessed the beneficial health effects and risks posed by the consumption of cereal-based weaning foods commercially available on the Ghanaian market with respect to the essential elements (Ca, Cl, Cr, Cu, Fe, K, Mg, Mn, Na, Se, V and Zn) and, non-essential, potentially toxic elements (As, Br, Hg, Pb and Sn). Twenty (20) different brands of weaning foods were purchased from various retail outlets in Accra and used for the study. Instrumental neutron activation analysis (INAA) and atomic absorption spectrometry [with flame atomisation (FAAS) and hydride generation (HGAAS)] were used in analysing the samples. Determination of Pb using FAAS was done following its extraction with dithizone. The analytical methods were validated using certified reference materials NIST 1568a (Rice flour) and NIST 1547 (Peach leaves). The levels (μg/g, in ranges) obtained for the elements were: As (< 0.025), Br (<0.17-402), Ca (405-2002), Cl (158-5521) and Cr (<0.03-1.23). Others are: Cu (0.83-55.80), Fe (1.07-11.78), Hg (< 0.025), K (49-3845) Mg (20-280) and Mn (0.84-38.94). The rest include: Na (13-1588), Pb (0.025-0.093), Se (0.145-0.317), Sn (35.8-91.8), V (<0.01-0.990) and Zn (0.50-7.17). The daily intakes of the essential elements were also estimated, and generally found to be lower than recommended values set either by the FAO/WHO, the European Food Safety Authority (EFSA), the US Food and Nutrition Board, or the Joint Societies for Nutrition of Germany, Austria and Switzerland. The estimated intake levels of the non-essential, potentially toxic elements As, Hg, Sn and Pb were all lower than their respective provisional tolerable weekly intake (PTWI) values established by the Joint FAO/WHO Expert Committee on Contaminants and Food Additives (JECFA). The results indicated that the analysed food samples were generally safe for consumption with respect to their content of the non-essential elements analysed. However, the contributions of the food samples to the daily essential element needs of the infant were mostly woefully inadequate, and this may not augur well for the proper growth and development of infants that consume them.