Department of Nuclear Agriculture and Radiation Processing

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    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.
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    Mutagenesis Of Cowpea for Early Maturity and Higher Yield
    (University of Ghana, 2020-10) Dorvlo, I.K
    ABSTRACT 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.
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    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.