Evaluation of some genotypes of maize (Zea mays L.) for tolerance to drought in Northern Ghana

Pot and field studies were conducted to screen twenty five genotypes of maize for tolerance to drought in Northern Ghana during the 2012 and 2013 cropping seasons.  For the pot studies, seeds were planted in June 2012 in 0.20 m × 0.30 m surface pots arranged in rows on a platform with a distance of 1 m between the rows. After emergence, 2 l of water was applied to the plants in each pot, once every week for the non-stressed treatments (control). To mimic drought conditions, the same amount of water was applied, but once every two weeks to the stress treatments. Treatments were replicated three times in a completely randomized design. For the field study, genotypes were evaluated on single-row plots of three replicates, in a randomized complete block design. Plants designated as control were planted at the normal and usual time of planting of maize in the study area (July 2013), whilst those subjected to water-stressed treatments were planted late (six weeks later) to ensure that their growth period coincides with the drought period.  Results on yield and agronomic parameters showed that three of the genotypes (GUMA03-OB, KOBN03-OB and SISF03-OB) were highly tolerant to drought, whilst eleven genotypes (NYAZ04-W, TAAN04, TAIS03, TZE-Y-DT-STR-C4, NYSW03-Y, NYIA03, DORKE SR, TZE-W-DT-STR-C4, NYFA04, KOBN04-R, and CHMA04) were moderately tolerant. The rest of the genotypes showed moderate to high levels of drought susceptibility. Drought plant rating and anthesis-silking interval (ASI) were significantly reduced when plants were watered throughout the experimental period (control) as compared to those stressed. However, grain yield, plant height, ear height, days to 50% anthesis, days to 50% silking, leaf area, chlorophyll content, fresh and dry shoot weight and root length were significantly higher (P < 0.05) for the non-stressed plants as compared to those subjected to water stress. In drought-prone geographical areas like Northern Ghana, genotypes such as GUMA03-OB, KOBN03-OB and SISF03-OB or their crosses can be used for increased grain yield

Preliminary studies on the response of onion (Allium cepa L.) to planting depth and NPK fertilizer application

AbstrActStudies were conducted at the department of Agronomy of the University fordevelopmentStudies in Nyankpala,ghana, from July tooctober 2011 and repeated in the same period in2012 to determine the response of onion to depth of planting and fertilizer application.onionbulbs of average fresh weight of 24 g were planted 0, 2, 4 and 6 cm deep from soil surface, andNPK (15:15:15) fertilizer at the rate of 0, 85, 170 and 255 kg ha-1was applied at the time ofplanting and 2 weeks after planting.the treatment combinations were replicated four times inrandomized complete block (rCb) design.the results indicated that planting 4 cm deep, andapplying NPK fertilizer at the rate of 85 kg ha-1produced the highest bulb size and fresh weightat harvest.bulbs planted 2 cm deep, which received no fertilizer application, produced the high-est number of bulbs at harvest, whilst those planted at the depth of 6 cm and fertilized with 170kg ha-1of NPK gave the least number of bulbs. Leaf production was highest when bulbs wereplanted 2 cm deep, and no NPK fertilizer application.tiller production was also highest whenbulbs were planted 4 cm deep and no NPK fertilizer application. In onion production, therefore,whilst NPK fertilizer may not be required for vegetative growth, it is important to apply thefertilizer to enhance bulb production. onion growers in the study area should plant onion bulbson Nyankpala soil series 4 cm deep, and apply NPK fertilizer at the rate of 85 kg ha-1to the soilfor good bulb yield.Original scientific paper. Received 03 Apr 14; revised 16 Sept 14

Understanding Lateritic Ore Agglomeration Behaviour as a Precursor to Enhanced Heap Leaching

Although nickel (Ni) laterite ores constitute the majority of Ni mineralization resource world-wide, in contrast to Ni sulphides, their processing via conventional beneficiation (e.g. multi-gravity and flotation) and hydrometallurgical routes is intractable as they are predominantly low grade and complex, both mineralogically and chemically. Due to their physico-chemical character-istics, low grade lateritic ores require more aggressive but costly chemical and hydrometallurgical techniques (e.g., leaching in high pressurized tanks) for value metal (Ni and Co) extraction. Processing such ores through cost-competitive heap (4-10 m high) leaching as an alternative, requires successful agglomeration of the feed into robust and porous granules. To date, produc-ing of granules with desirable attributes poses a major geotechnical challenge to industry. In the present work, we investigate agglomeration behaviour of siliceous goethite Ni laterite ore and selected oxides and clay minerals (hematite, quartz and kao-linite) which constitute the predominant host gangue phases of typical low grade Ni laterite ores. Fundamental knowledge and understanding of the agglomeration mechanisms and kinetics which are essential for producing robust real ore granules, and pivotal to the subsequent heap leaching process, are gleaned. Isothermal, batch agglomeration tests involving 30 and 44 % w/w sulphuric acid solution as a binder indicated that 5 – 40 mm granules of differing roughness and morphologies were produced in 8-14 min. The results showed feed characteristics (e.g., mineralogy and particle size distribution) and binder content (15-25 wt.%) dependent agglomeration behaviour. Slow agglomerate nucleation and growth were displayed by the kaolinite clay min-eral whilst the oxides exhibited faster agglomeration kinetics. Siliceous goethite feed ore fine/coarse ratio, H2SO4 binder dosage and acid content, product drying temperature and aging conditions, all showed significant impact on agglomeration mecha-nisms (e.g., particle wetting, nucleation and growth processes) and granule attributes (e.g., size and strength). Agglomerates strength increased with increasing fine/coarse particle ratio

Assessing the technical efficiency of maize production in northern ghana: the data envelopment analysis approach

Maize is a major source of food and cash for smallholder farmers. However, average yield in Ghana is less than a third of the achievable yield and thus the need to close this gap by improving the technical efficiency of farming households through employing the right combination of productive resources to achieve food sustainability. This study used the input-oriented data envelopment analysis to examine the technical efficiency of maize production in northern Ghana1 using cross-sectional data for the 2011/2012 cropping season. The mean technical efficiency was 77%, giving credence to the existence of production inefficiency. Technically, efficient farmers used an average of 395.80 kg of chemical fertilizer, 27.04 kg of seed, 4.04 l of weedicides and hired labour of three persons to produce a yield of 2.34 tons/ha of maize. Largely, maize production exhibited increasing returns to scale. Agricultural mechanization and level of formal education did not have positive effects on technical efficiency, whereas agricultural extension had a positive effect on technical efficiency. Technical efficiency in maize production could be improved through informal and non-formal educational platforms where farmers without formal education learn improved cultivation practices. The agricultural extension department should be strengthened to provide effective extension services to farmers to improve on their technical efficiency. Animal and other non-mechanized power sources are complementary technologies and as such should be allowed to co-exist in Ghanaian agriculture

Interplay between foetal haemoglobin, micronutrients and oxidative stress biomarkers in sickle cell anaemia children

Foetal haemoglobin (HbF) has been speculated to have an impact on the quantity of micronutrients and the latter also have a role to play in oxidative stress (OS) in sickle cell anaemia (SCA). No previous study in Ghana has examined the interplay of these factors together among SCA children. This study compared the levels of OS biomarkers (8-hydroxy-deoxyguanosine [8-OHdG] total antioxidant capacity [TAC]) and micronutrients (zinc and copper), and their relationship with HbF in SCA and sickle cell negative, apparently healthy children. This case-control study recruited 58 SCA (out-patients [n = 42] and in-patients [n = 16]) children aged 1–14 years as cases and 62 sickle cell negative children as controls from the Sickle Cell Unit at the Eastern Regional Hospital, Ghana. The micronutrients were measured using the atomic absorption spectrophotometer (AAS) whereas OS biomarkers and HbF were assayed using enzyme-linked immunosorbent assay (ELISA). SCA out-patients had a significantly higher level of HbF compared to HbA patients (p = 0.035). SCA in-patients had significantly increased levels of zinc, but a reduced 8-OHdG than SCA out-patients compared to control group (p \u3c 0.05). HbF correlated significantly (r = 0.318, p \u3c 0.038) with zinc in SCA out-patients. Micronutrients are essential in maintaining the redox status in SCA out-patients and HbF can influence some micronutrients

Quality of glycemic control in type 2 diabetes mellitus (T2DM) and its association with markers of coagulation and inhibitors of fibrinolysis: A case–control study in the upper west region, Ghana

Background and Aims: Type 2 diabetes mellitus (T2DM) individuals are at a higher risk of developing diabetes complications, with approximately 80% complication-related mortality. The increased morbidity and mortality among T2DM patients are partly due to dysregulated hemostasis. This study determined the quality of glycemic control in T2DM and its association with markers of coagulation and inhibitors of fibrinolysis. Methods: This case–control study recruited 90 participants involving: 30 T2DM patients with good glycemic control, 30 with poor glycemic control, and 30 nondiabetic subjects as controls at a Municipal Hospital in Ghana. Fasting blood glucose, glycated hemoglobin, activated partial thromboplastin time (APTT), prothrombin time (PT), calculated international normalized ratio (INR), and full blood count (FBC) were determined for each respondent. Plasma levels of plasminogen activator inhibitor-1 (PAI-1) and thrombin activatable fibrinolysis inhibitor (TAFI) were determined using the solid-phase sandwich enzyme-linked immunosorbent assay method. Data were analyzed using R language software. Results: Plasma PAI-1 antigen levels were significantly higher in the participants with poor glycemic control as compared to participants with good glycemic control (p \u3c 0.0001). There was no significant difference in plasma TAFI levels between the participants with poor glycemic control as compared to participants with good glycemic control (p = 0.900). T2DM patients had significantly shorter APTT, PT, and INR than controls (p \u3c 0.05). At a cut-off of ≥ 161.70 pg/μL, PAI was independently associated with increasing odds (adjusted odds ratio = 13.71, 95% confidence interval: 3.67–51.26, p \u3c 0.0001) of poor glycemic control and showed the best diagnostic accuracy for poor glycemic control (area under the curve = 0.85, p \u3c 0.0001). Conclusion: PAI-1 levels were significantly increased in T2DM with poor glycemic control and emerged as the best predictor for poor glycemic control. Good glycemic management to control the plasma levels of PAI-1 is required to prevent hypercoagulability and thrombotic disorders

Association between micronutrients, oxidative stress biomarkers and angiogenic growth mediators in early and late-onset preeclamptic Ghanaian women

Objectives: Micronutrients, especially calcium (Ca) and magnesium (Mg) are reported to reduce preeclampsia events via several factors such as endothelial cell control, optimal oxidative stress and a balanced angiogenic growth mediator. We evaluated the association of micronutrients with oxidative stress biomarkers, and angiogenic growth mediators in early-onset preeclampsia and late-onset preeclampsia. Methods: This case-control study recruited 197 preeclampsia (early-onset preeclampsia = 70 and late-onset preeclampsia = 127) as cases and 301 normotensive pregnant women as controls from the Komfo Anokye Teaching Hospital, Ghana. Samples were collected after 20 weeks of gestation for both cases and controls and estimated for Ca, Mg, soluble fms-like tyrosine kinase-1, placental growth factor, vascular endothelial growth factor-A, soluble endoglin, 8-hydroxydeoxyguanosine, 8-epiprostaglandinF2-alpha and total antioxidant capacity. Results: Early-onset preeclampsia women had significantly lower levels of Ca, Mg, placental growth factor, vascular endothelial growth factor-A and total antioxidant capacity but higher levels of soluble fms-like tyrosine kinase-1, soluble endoglin, 8-epiprostaglandinF2-alpha, 8-hydroxydeoxyguanosine, soluble fms-like tyrosine kinase-1/placental growth factor ratio, 8-epiprostaglandinF2-alpha /placental growth factor ratio, 8-hydroxydeoxyguanosine/placental growth factor ratio and soluble endoglin/placental growth factor ratio than late-onset preeclampsia and normotensive pregnant women (p \u3c 0.0001). Among the early-onset preeclampsia women, the first and second quartile for serum placental growth factor, first quartile for vascular endothelial growth factor-A and total antioxidant capacity and the fourth quartiles for serum sEng, serum sFlt-1, 8-epiPGF2 and 8-OHdG were independently associated with low Ca and Mg (p \u3c 0.05). Among late-onset preeclampsia women, the fourth quartile for soluble fms-like tyrosine kinase-1 was independently associated with low Ca and Mg (p \u3c 0.05). Conclusion: Magnesium and calcium are associated with an imbalance in angiogenic growth mediators and oxidative stress biomarkers among preeclampsia women, particularly early-onset preeclampsia. Serial and routine measurement of these micronutrients would allow the monitoring of poor placental angiogenesis while enabling an understanding of the triggers of increased oxidative stress and reduced antioxidant in preeclampsia

Coagulation factors and natural anticoagulants as surrogate markers of preeclampsia and its subtypes: A case-control study in a Ghanaian population

Preeclampsia (PE) is associated with endothelial injury and hemostatic abnormalities. However, the diagnostic role of coagulation parameters and natural anticoagulants in predicting PE has not been explored in Ghana. This study assessed plasma levels of these factors as surrogate markers of PE and its subtypes. This case-control study included 90 women with PE (cases) and 90 normotensive pregnant women (controls). Blood samples were drawn for the estimation of complete blood count and coagulation tests. The prothrombin time (PT), activated partial thromboplastin time (APTT), and the calculation of the international normalized ratio (INR) were determined by an ACL elite coagulometer while the levels of protein C (PC), protein S (PS), antithrombin III (ATIII), and D-dimers were also measured using the solid-phase sandwich enzyme-linked immunosorbent assay (ELISA) method. All statistical analyses were performed using the R Language for Statistical Computing. Results showed significantly (p \u3c .05) shortened APTT (28.25 s) and higher D-dimer levels (1219.00 ng/mL) among PE women, as well as low levels of PC (1.02 g/mL), PS (6.58 g/mL), and ATIII (3.99 ng/mL). No significant difference was found in terms of PT and INR. From the receiver operating characteristic analysis, PC, PS, and ATIII could significantly predict PE and its subtypes at certain cutoffs with high accuracies (area under the curve [AUC] ≥ 0.70). Most women with PE are in a hypercoagulable state with lower natural anticoagulants. PC, PS, and ATIII are good predictive and diagnostic markers of PE and its subtypes (early-onset PE [EO-PE] and late-onset PE [LO-PE]) and should be explored in future studies