Theses

Growth and nutrient uptake response of cocoa seedlings (Theobroma cacao) to different growth media at the nursery

2024-10-28T09:50:29Z

Growth and nutrient uptake response of cocoa seedlings (Theobroma cacao) to different growth media at the nursery Mornyuie, A.O. A study was conducted in the nursery house of Mabang Megakarya Selection Programme, a substation of the Cocoa Research Institute of Ghana from April 2022 to September 2022 to determine the growth and nutrient uptake response of cocoa (Theobroma cacao) seedlings to different growth media at the nursery. The treatments comprised three base-materials viz: Topsoil (TS), Rice husk (RH) and Sawdust (SD) amended with three rates of rice husk biochar (RHB) at 75%: 25%, 50%:50% and 25%:75% and two rates of cocoa pod husk-based compost (CPHC) at 90%:10% and 80%:20% (base-media: amendment on v/v). The respective amounts of media combinations were mixed thoroughly and filled into polybags with dimensions 18 cm wide x 25 cm high. The treatments were arranged in a completely randomize design (CRD) with three replications. Seeds of cocoa hybrid clone C69 were sowed into the treatment pots. Cocoa seed germination was recorded at 14 and 17 days after sowing (DAS). Seedling growth and biomass production were measured at 2, 4 and 6 months after germination (MAG). Leaf nutrient concentration was analysed at six MAG and nutrient uptake calculated. Result indicated that at 14 DAS, seed germination was 100 % in potting media with TS50:RHB50 and 100 SD and these were significantly (p<0.05) higher than in all other treatments. The result showed that media type TS50:RHB50 significantly (p<0.05) increased number of leaves, plant height, stem diameter, tap root length, leaf chlorophyll content, leaf area and plant biomass production at 6 MAG. There was significant positive correlation between plant growth parameters at 6 MAG. Plant leave nutrients (N, P, K, Ca, and Mg) uptake were significantly (p<0.05) higher in potting media with TS50:RHB50 and TS90:CPHC10. Generally, TS50:RHB50 was the best growth media and produced vigorous cocoa seedlings.

Remote sensing-based land degradation assessment to inform sustainable development goal 15.3: a case study in Ghanaian Savannah, West Africa

2024-10-28T09:44:45Z

Remote sensing-based land degradation assessment to inform sustainable development goal 15.3: a case study in Ghanaian Savannah, West Africa Mukura, G.J. Land degradation (LD) continues to be a global problem affecting humanity and their livelihoods. Like other African countries, Ghana is one of the countries with elevated levels of LD. However, LD assessments in Ghana have been far and wide and it has not been consistent. There have not been any recent assessments done to inform the SDG indicator 15.3.1 in Ghana. This study therefore focused on the Northern, North East, and Upper East of Ghana and bridged the information gaps on LD. This study was conducted within the three northern regions of Ghana, the Northern Region, the North East, and the Upper East Region. The study methods comprised 250m Modis data and high-resolution remote sensing images in 30m Landsat data and subsequently survey from the International Institute for Tropical Agriculture. Agriculture is the primary economic activity, within these regions. Collected data were handled in R Programming Language 4.3.2. The study found that baselines were 50.16% degraded, 40.43% stable, and 9.11% improvement in the Northern Region, and 57.61% degraded, 35.4% stable, and 6.99% improvement in the North East, and 40.35% degraded, 48.24% stable and 11.41% improvement in Upper East. In the adopted approach the study found that for the Northern 81.19% were stable, 18.506% improved, and 0.29% degraded, in the North East 81.02% were stable and 18.66% degraded and 0.39% improved, and Upper East 80.00% stable, 18.18% degraded and 1.81improving. The earth observation almost unanimously agreed with the survey which saw the overall prevalence of land degradation within the regions was 76.8%. However, the survey data was primarily for two regions. The prevalence of LD was significantly higher in the Northern region (60.7%) than in the Upper East region (48.3%; p = 0.003). Of the types of land degradation, most were as a result of soil erosion by water (78.9%) followed by one-third by biological degradation (33.8%) and one-quarter by physical soil deterioration (24.6%). LD as a result of soil erosion by biological degradation (p = 0.018) was significantly different between the regions of the study with the Northern region having predominant LD by biological degradation (43.1%) compared to the Upper East region (24.3%). Furthermore, compared to the Norther region, the Upper East region (cOR: 3.21, 95% CI: (1.47-7.00); p = 0.003) had a 3-odds increased likelihood of land degradation. Specifically, Bolga district (cOR: 26.00, 95% CI: (2.29-295.64); p = 0.009) within the Upper East region had a 26-odds increased likelihood of land degradation. Causes of land degradation including water, physical soil deterioration, and direct and natural causes of land degradation were significantly different between the regions of the study (p < 0.05). In addition, land degradation as a result of improper soil management is significantly different between the regions of the study (p < 0.05). LD remains high in the Northern, North East and Upper East regions of Ghana. Addressing land degradation requires region-specific tailored interventions to the predominant forms of land degradation and causes in Ghana.

Genetic diversity in African yam bean [Spenostylis stenocarpa (Hochst ex A. Rich.) Harms] collection

2024-10-28T09:20:19Z

Genetic diversity in African yam bean [Spenostylis stenocarpa (Hochst ex A. Rich.) Harms] collection Ebiti, E.K. African Yam Bean (AYB) is an underutilized legume with great potential of providing an inexpensive and sustainable solution to malnutrition and food insecurity in Sub-Saharan Africa. However, its genetic variability is not yet fully exploited and documented. To enhance the full exploitation and improvement of the crop, there is a need for knowledge of its genetic diversity. This research was therefore carried out to assess the genetic diversity in AYB germplasm collection using agro-morphological traits, genetic markers, nutritional, anti-nutritional, and mineral composition. Thirty AYB accessions were evaluated during the 2021 cropping season at the International Institute of Tropical Agriculture (IITA). The field experiment was laid out in a Randomized Complete Block Design with three replicates. The accessions were evaluated for 28 agro- morphological and 16 categorical characters using the IITA Reference Guide. Seeds and tubers of the AYB accessions were evaluated for nutritional values using the Association of Official Analytical Chemists (A.O.A.C) method of analysis. Accessions were genotyped by DArTseq high-depth technology. A total of 5,142 Single Nucleotide Ppolymorphism (SNP) markers were generated and quality control was performed on the basis of Call Rate <0.70, marker reproducibility (RepAvg) <0.95, >10% missing values, and <0.01 minor allele frequency. A total of 1,805 high-quality and genome-wide DArTseq SNP markers were retained after quality control (QC) and used for the diversity study. Data were subjected to analysis of variance at α0.05, while cluster analysis was performed using R-package. There were significant difference among the AYB accessions for the traits evaluated. The earliest days to peduncle initiation (49 days), days to first flowering (64 days), and 50% flowering (73 days) were observed in TSs-519. Also, the highest pod weight per plant (59.64 g), number of seeds per pod (94), and seed weight per pod (28.08 g) were observed in TSs-519. Accessions TSs-104 had the earliest days to pod maturity (122 days). Moisture content (MC) in AYB tubers ranged from 10.25±0.03% (TSs-104) to 10.78±0.14% (TSs-130), while MC in AYB seeds ranged from 10.26±0.13% (TSs-674) to 10.64±0.13% (TSs-561). Protein content (PC) in AYB tubers ranged from 9.69±0.09% (TSs-130) to 9.88±0.08% (TSs-104). Whereas, the PC in the seeds ranged from 19.91±0.50% (TSs-561) to 24.40±0.33% (TSs-562). Carbohydrate content (CC) in AYB tubers ranged from 71.23±0.50% (TSs-104) to 72.13±0.56% (TSs-130), while CC in AYB seeds ranged from 48.03±0.84% (TSs-642) to 58.81±0.80% (TSs-613). Trypsin inhibitor in AYB tubers ranged from 6.48±0.70 mg/g (TSs-104) to 7.47±0.70 mg/g (TSs-130), while trypsin inhibitor in AYB seeds ranged from 1.987±0.00 mg/g (TSs-634) to 38.30±0.70mg/g (TSs-636). Zinc content in AYB seeds ranged from 23.28±0.56 ppm (TSs-519) to 31.40±0.41 ppm (TSs-642). Heterozygosity of 7.79% was observed in the AYB population. The AYB accessions were grouped into four main clusters based on the agro-morphological traits and 1,805 SNP markers. Genetic diversity exists among the African yam bean accessions based on morphological traits, nutritional, anti-nutritional, and mineral composition. The accessions were also highly discriminated based on the genetic markers.

Evaluation de l'efficacite de l'Aflasafe dans la lutte contre l'Aspergillus spp. synthetisant l'aflatoxine dans les bassins de production de sorgho, de mais et de l'arachide au Mali

2024-08-17T02:01:03Z

Evaluation de l'efficacite de l'Aflasafe dans la lutte contre l'Aspergillus spp. synthetisant l'aflatoxine dans les bassins de production de sorgho, de mais et de l'arachide au Mali Konate, M. Les aflatoxines sont des mycotoxines dont l’exposition chronique engendre des problèmes graves de santé comme le cancer du foie, le retard de croissance des enfants et l’affaiblissement du système immunitaire. Elles sont couramment rencontrées dans les denrées alimentaires cultivées comme le sorgho (Sorghum bicolor (L.) Moench), le maïs (Zea mays L.) et l’arachide (Arachis hypogaea L.). Aflasafe est un bio pesticide préconisé pour lutter contre les champignons producteurs des aflatoxines. L’objectif de cette étude est de contribuer à l’amélioration de la qualité sanitaire des aliments. Une analyse quantificative des aflatoxines par l’automate « RAPTOR-NEOGEN -RPT-6576 » a été réalisée sur 1252 échantillons de denrées issues de parcelles traitées par l’Aflasafe (626) et de parcelles non traitées (626). Les résultats obtenus illustrent une moyenne totale allant de 2,6 ppm dans les échantillons traités contre 46,54 ppm dans les échantillons contrôles pour le district de Bamako soit un taux de réduction de 94,41 %. Dans la région de Kayes, les échantillons traités ont obtenu 3,87 ppm contre 28,11 ppm dans les champs témoins soit un taux de réduction de 86,23 %. Quant à la Région de Koulikoro, la somme des moyennes de l’ensemble des échantillons traités étaient de 3,09 ppm contre 51,39 ppm non traités soit un taux de réduction de 93,99 %. Pour la Région de Sikasso, les résultats obtenus dans les échantillons traités étaient de 3,29 ppm contre 29,33 ppm soit un taux de réduction de 88,78 % dans cette région. Enfin pour la région de Ségou on a obtenu 2,59 ppm dans les champs traités contre 39,06 ppm dans les échantillons témoins soit un taux de réduction de 93,37 %. La moyenne récapitulative de tous les échantillons traités dans les différentes régions est de 3,08 ppm contre 38,89 ppm dans les échantillons témoins soit un taux de réduction de 92,08 %. Ces résultats obtenus dans les champs traités suggèrent que les différentes souches d’Aspergillus flavus (Link, 1809) atoxinogènes testés au Mali pour la gestion efficace de l’aflatoxine peuvent être exploitées dans des approches biologiques pour réduire la concentration d’aflatoxine dans les aliments. Aflatoxins are mycotoxins whose chronic exposure causes serious health problems such as liver cancer, stunted growth in children and weakened immune systems. They are commonly found in cultivated foods such as sorghum (Sorghum bicolor (L.) Moench), corn (Zea mays L.) and peanuts (Arachis hypogaea L.). Aflasafe is a bio-pesticide recommended for the control of aflatoxin producing fungi. The objective of this study is to contribute to the improvement of food safety. A quantificative analysis of aflatoxins by the "RAPTOR-NEOGEN -RPT-6576" automaton was carried out on 1252 samples of foodstuffs from plots treated with Aflasafe (626) and from untreated plots (626). The results show a total average of 2.6 ppm in treated samples versus 46.54 ppm in control samples for the Bamako district, a reduction rate of 94.41%. In the Kayes region, the treated samples obtained 3.87 ppm against 28.11 ppm in the control fields, i.e. a reduction rate of 86.23%. In the Koulikoro Region, the sum of the averages of all treated samples was 3.09 ppm compared to 51.39 ppm in the untreated samples, for a reduction rate of 93.99%. For the Sikasso Region, the results obtained in the treated samples were 3.29 ppm versus 29.33 ppm, for a reduction rate of 88.78% in this region. Finally, in the Segou region, the results obtained in the treated fields were 2.59 ppm compared to 39.06 ppm in the control samples, for a reduction rate of 93.37%. The summary average for all treated samples in the different regions was 3.08 ppm compared to 38.89 ppm in the control samples, for a reduction rate of 92.08%. These results obtained in the treated fields suggest that the different atoxinogenic Aspergillus flavus (Link, 1809) strains tested in Mali for effective aflatoxin management can be exploited in biological approaches to reduce aflatoxin concentration in food.