Browsing by Author "Amoatey, C.A."
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Item Agro–Input Use in Peri–Urban Okra Productionin the Greater Accra Region(University of Ghana, 2015-03) Abla, D.E.; Amoatey, C.A.; Boateng, S.B.; University of Ghana, College of Basic and Applied Sciences, School of Agriculture, Department of Crop ScienceA series of studies were carried out in the Greater Accra region from October, 2012 to May, 2013 to ascertain agro-input usage in okra production and its effects on quality of production and the produce. Studies comprised a survey, two field studies (an on–farm trial and a field experiment) and one laboratory study. For the survey, data were collected through the administration of questionnaires and analyzed using Statistical Package for Social Sciences (SPSS) software (version 18). A randomized complete block design (RCBD) with three treatments as follows: combination of 25g/L permethrin + 475g/L pirimiphos–methyl insecticide + Propaquizafop–100g Herbicide; 25g/L permethrin + 475g/L pirimiphos–methyl + Imidacloprid insecticides + Propaquizafop–100g herbicide and the Control (no pesticide) for the on-farm experiment and 25g/L permethrin + 475g/L pirimiphos–methyl; Neem extract oil at a rate of 3.3mL/L in a knapsack sprayer and a Control (no pesticide) for the field experiment; was used for the field studies with four replicates, while a completely randomized design (CRD) with three replicates was used for the laboratory study. Data were collected on vegetative, reproductive and quality characteristics of okra. Data from field and laboratory studies were analyzed using Analysis of Variance (ANOVA), Genstat Statistical Package (11th edition). The results showed that the farmers in peri-urban okra production were predominantly male (70%) and used agrochemicals widely in their production. None had used certified okra seed for production. Most of these farmers had only basic education which significantly impacted negatively on their ability to read labels on agrochemicals. On–farm trial produced okra which performed significantly better in terms of plant height, stem girth, leaf production, fresh and dry weights of plants compared to that of the field experiment. The laboratory study showed a 10% rapid deterioration and reduced sliminess of okra from plots treated with a mixture of inorganic agrochemicals and botanicals although these fruits were aesthetically more appealing at harvest compared to the controls.Item Efficacy of Four Herbicide Groups on Weed Control, Growth and Yield of Maize(University of Ghana, 2013-07) Mienwipia, A.N.; Amoatey, C.A.; Ofosu-Anim, J.Two field studies were carried out from July 2012 to February 2013 to determine the efficacy of four groups of herbicide on weed control, growth and yield of maize (Zea mays L.) and to investigate the influence of their residual effect on weed succession, rotation crop, soil nutrient status and microbial population at the University Farm, Legon. The experiments, laid out in randomized complete block design, consisted of four replications of eight herbicide treatments from four herbicide groups (Glyphosate: Glyphader, Nwura Wura; Paraquat: Conti-quat, Kwatriqua; Atrazine: Sun-Atrazine, Atranex; 2, 4-D: Sun-2, 4-D, Bextra 2,4-D) applied at two concentrations (lower and higher recommended rates). Glyphader and Nwura Wura, which are glyphosates were applied pre-plant at 1.5 and 3.0L/ha and 2.5 and 4.0L/ha, respectively. Conti-quat and Kwatriqua (derivatives of paraquat) were applied pre-plant at 1.0 and 2.0L/ha and 1.5 and 2.0L/ha, respectively. Sun-Atrazine and Atranex are atrazines and were applied pre-emergence at 3.0 and 4.0L/ha and 1.25 and 2.5L/ha, respectively, whilst Sun-2, 4-D and Bextra 2, 4-D, derivatives of 2, 4-D, were also applied pre-emergence at 2.0 and 4.0L/ha and 1.5 and 2.5L/ha, respectively. The control plots were weeded manually only. Results showed that all herbicides applied increased weed mortality, most especially in the pre-emergence applications. The results also indicated that plants in the control plots had higher crop growth rate and net assimilation rate for low application rate. All herbicide treated plots positively influenced growth and yield of the maize. The highest maize yield per hectare (9779.0kgha -1 ) was obtained in Sun-Atrazine treated plots, followed by Nwura Wura treated plots (9700.0kgha -1 ) and Sun-2, 4-D treated plots (9770.0kgha -1 ). Use of the herbicides positively influenced crop growth and increased biomass yield of both maize and cowpea used as second crop. Results of soil analyses revealed that residual herbicides did not have any negative influence on nutrients status and microbial population of the soil.Item Exploring alternative use of medicinal plants for sustainable weed management(Sustainability (Switzerland), 2017) Appiah, K.S.; Mandarin, H.K.; Osivand, A.; Kpabitey, S.; Amoatey, C.A.; Oikawa, Y.; Fujii, Y.This paper presents the first application of ethnobotanical studies to screen for allelopathic species among medicinal plants for sustainable weed management. This study assesses the possible relationship between ethnobotanical indices and allelopathy of medicinal plants. Ethnobotanical data were collected in 2016 by using semi-structured interviews with 140 informants in the Ejisu-Juaben Municipality, Ghana. Data were analysed using statistical tool and ethnobotanical indices including use value (UV), Fidelity Level (FL), Relative Frequency of Citation (RFC). The Sandwich and Dish pack methods were respectively used to evaluate allelopathy through leachates and volatiles of collected samples. Ninety-five species belonging to 43 families are reported in this study, with leaves (52%) cited the most utilised plant part. Cleistopholis patens (UV = 0.54; FL = 90.7%; RFC = 0.37) and Ocimum gratissimum (UV = 0.37; FL = 38.4%; RFC = 0.35) were among the most cited species. Thirty-two species showed inhibition (≥49.3%) by leachates, while twenty-four species were found with potential volatile inhibitory compounds against lettuce radicle growth. There was a significant positive correlation (Pearson) between the UV and RFC of medicinal plants and allelopathy by leaf leachates (r = 0.639 **; p = 0.01 and r = 0.653 **; p = 0.01 respectively). This systematic documentation of medicinal plants in Ejisu-Juaben Municipality shows medicinal plants with ethnomedicinal values and potential allelopathy that can be utilised in sustainable weed control. © 2017 by the authors. Licensee MDPI, Basel, Switzerland.Item Influence of Spacing and Plant Age at First Harvest on the Growth, Development, and Yield of Three Roselle (Hibiscus sabdariffa L.) Cultivars(University of Ghana, 2013-07) Abukari, S.; Norman, J.C.; Blay, E.T.; Amoatey, C.A.A field experiment was conducted to examine optimum plant population and compare yields of three local roselle cultivars; namely Bihi, Mogla 1 and Mogla 2 planted at four different spacings and harvesting at 31 days after planting by pruning the plant at 13.0 cm high. Subsequent harvesting of shoots was done at fortnightly intervals. The spacings were; 30cm x 30cm, 30cmx 35cm, 30cm x 40cm, and 30cm x 45cm. A pot experiment was also carried out to determine the appropriate plant age at first harvest (PAFH) of two of the roselle cultivars; Bihi and Mogla 1. Three PAFH used were 31, 38 and 45 days after planting. The field and pot experiments were conducted at the University of Ghana Farm, Legon from June 2012 to January 2013. A randomized complete block design was used and replicated four times for the field experiment and three times for the pot experiment. In the field experiment, plant growth parameters studied were harvested leaves, stems and petioles numbers, fresh and dry weights were recorded at 31 days after planting and depending on the type of treatment of PAFH in the pot experiment. Other data collected were; plant height at first harvest, number of leaves per plant, number of new shoots per plant, new stem diameter, leaf area, leaf area index, yield and yield components. Results revealed that subsequent harvesting did not significantly enhance the production of more harvested leaves and stems in the field experiment; and reduced new shoots length in both field and pot experiments. The Bihi cultivar was taller at first harvest than Mogla 1 and Mogla 2 at closer spacing than wider spacing. PAFH of 45 days produced taller plants, more harvested leaves and stems than 31 and 38 days with insignificant differences between 38 days PAFH . The studies showed that optimum spacing was 30cm x 30cm (222,222 plants/ha). Mogla 1 produced higher fresh leaves,stems, shoot yields (t/ha), leaf/stem ratio than Bihi and Mogla 2. Appropriate plant age at first harvest of 38 days after sowing is recommended for continuous harvesting by pruning as a leafy vegetable to maximize production.Item Involvement of Carnosic Acid in the Phytotoxicity of Rosmarinus officinalis Leaves(Toxins, 2018-11) Appiah, K.S.; Mardani, H.K.; Omari, R.A.; Eziah, V.Y.; Ofosu-Anim, J.; Onwona-Agyeman, S.; Amoatey, C.A.; Kawada, K.; Oikawa, Y.; Fujii, Y.Weeds are rapidly developing resistance to synthetic herbicides, and this can pose a threat to the ecosystem. Exploring allelopathic species as an alternative weed control measure can help minimize the ecological threat posed by herbicide-resistant weeds. In this study, we aimed to evaluate the contribution of some polyphenols to the allelopathy of rosemary (Rosmarinus officinalis L.). The phytotoxic effects of rosemary (leaves, roots, inflorescences, and stems) crude extracts were tested on lettuce (Lactuca sativa L.). Soils incorporated with dried rosemary leaves were also tested on test plants. Reversed-phase high-performance liquid chromatography (HPLC) analysis was used to determine the content of some polyphenols (caffeic, ferulic, gallic, rosmarinic, carnosic, and chlorogenic acids) in rosemary. The specific activity and total activity of crude extracts and individual compounds were evaluated using lettuce. The crude extract of rosemary leaves showed the highest growth inhibitory effect among the rosemary organs tested. Soil amended with rosemary leaf debris reduced the dry matter and seed emergence of lettuce. Carnosic acid was the main compound detected in rosemary leaves and had a high specific activity when tested on lettuce. During the seed germination period, there was observed filter paper coloration among the test plants treated with carnosic acid (250 µg/mL). The high concentration and strong inhibitory effect of carnosic acid could explain the inhibitory activity of the rosemary leaf extract. Hence, we conclude based on the total activity estimation that carnosic acid among the other tested compounds is the major allelochemical in rosemary leaves. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.Item Limited effects of shade on physiological performances of cocoa (Theobroma cacao L.) under elevated temperature(Environmental and Experimental Botany, 2022) Mensah, E.O.; Asare, R.; Vaast, P.; Amoatey, C.A.; Markussen, B.; Owusu, K.; Asitoakor, B.K.; Asitoakor, A.Shade is one of the recommended management solutions to mitigate the effects of heat stress, which is a major challenge for cocoa production globally. Nevertheless, there are limited studies to verify this hypothesis. Here, we evaluate the effects of heat and shade on cocoa physiology using experimental plots with six-month old potted seedlings in a randomized complete block design. Infrared heaters were applied for one month to increase leaf temperatures by an average of 5–7 ºC (heat treatment) compared with no heat (unheated treatments), and shaded plants were placed under a shade net removing 60% of the light compared with no shade (sun treatments). Plants under heat treatments in sun and in shade showed severe reduction in photosynthesis. Measurements of chlo rophyll fluorescence and photosynthetic light response curves indicated that heat caused damages at photo system II and additionally resulted in lower rates of maximal photosynthesis. Temperature optima for photosynthesis were at 31–33 ºC with only small differences between treatments, and as light saturation was reached at low PAR levels of 325 – 380 µmol m− 2 s − 1 in shade and 427 – 521 µmol m− 2 s − 1 in sun, ambient rates of photosynthesis were comparable between sun and shade treatments. Heat treatments resulted in decreased concentrations of chlorophyll and changed pigment composition, reduced specific leaf areas, and plant biomass. While shade may benefit cocoa seedlings, our results indicate that the positive effects may not be sufficient to counteract the negative effects of increased temperatures on cocoa physiology.Item Seasonal Changes in the Plant Growth-Inhibitory Effects of Rosemary Leaves on Lettuce Seedlings(Plants, 2022) Appiah, K.S.; Omari, R.A.; Onwona-Agyeman, S.; Amoatey, C.A.; Ofosu-Anim, J.; Smaoui, A.; Arfa, A.B.; Suzuki, Y.; Oikawa, Y.; Okazaki, S.; Katsura, K.; Isoda, H.; Kawada, K.; Fujii, Y.Plant biodiversity has been studied to explore allelopathic species for the sustainable management of weeds to reduce the reliance on synthetic herbicides. Rosemary (Rosmarinus officinalis L., syn Salvia rosmarinus Spenn.), was found to have plant growth-inhibitory effects, and carnosic acid was reported as an allelochemical in the plant. In this study, the effects of seasonal variation (2011–2012) on the carnosic acid concentration and phytotoxicity of rosemary leaves from two locations in Tunisia (Fahs and Matmata) were investigated. The carnosic acid concentration in rosemary leaves was determined by HPLC, and lettuce (Lactuca sativa L.) was used as the receptor plant in the phytotoxicity bioassay. The highest carnosic acid concentration was found in rosemary samples collected in June 2011, which also had the highest inhibitory activity. Furthermore, a significant inverse correlation (r = 0.529; p < 0.01) was found between the inhibitory activity on lettuce hypocotyl and the carnosic acid concentration in rosemary leaves. Both temperature and elevation had a significant positive correlation with carnosic acid concentration, while rainfall showed a negative correlation. The results showed that the inhibitory effects of rosemary leaf samples collected in summer was highest due to their high carnosic acid concentration. The phytotoxicity of rosemary needs to be studied over time to determine if it varies by season under field conditions.Item Variation in Floral Morphology, Fruit Set and Seed Quality of Garden Egg (Solanum Aethiopicum Var Gilo) Germplasm in Ghana(University of Ghana, 2013-07) Denkyirah, E.K.; Ofori, K.; Amoatey, C.A.Two field experiments and a laboratory experiment were conducted at the University of Ghana, Farm, Legon and the Department of Crop Science respectively between June 2012 and May 2013 to determine the variation in floral morphology, fruit set and seed quality of twelve garden egg accessions. A randomized complete block design was used for the field experiments while a completely randomized design was used for the laboratory experiment. Data were collected on vegetative, reproductive, yield and seed characteristics. Results showed that garden egg flowers among the accessions were either solitary (single) or clustered (two or more flowers) with the stigma protruding either above (long styled flower), on the same level (medium styled flower) or below (short styled flower) the anther tips. Variations were observed among and within flowers of the same accessions. Flower number per inflorescence also varied within individual accessions as well as among accessions. Flower drop was very low in the solitary flowering type but was significantly high in the clustered flowering type. The fruit characteristics observed among accessions varied considerably in size, shape, immature fruit colour and fruit surface [characteristics of fruit wall (exocarp)] in both field experiments. Fruit colour (exocarp) among accessions varied from white to green to various combinations of green and white. Significant (p˂0.05) differences among accessions were observed for fruit weight, fruit length and diameter. Fruit set from long and medium styled flowers contained a higher number of seeds per fruit compared to fruit set from the short styled flowers. The latter contained about 50% less seeds on average compared to the former. There were significant (p˂0.05) differences among accessions for the number of whole seeds per fruit and the germination percentage. Although the 100 seed weight was statistically significant (p˂0.05) for the different accessions, those with the mixed type of inflorescence showed no significant differences. Results showed that fruit set in garden egg was not directly related to the stigma position in relation to the anther tip. However, seed content was positively influenced by the stigma position in relation to the anther tip.