Isaac Asante

RAPD-based genetic diversity study of fifty cassava (Manihot esculenta Crantz) genotypes

Fifty cassava clones were studied using RAPD technique. They included landraces from the Wenchi, Nkoranza, Dormaa Ahenkoro and Asonafo districts of the Brong Ahafo region of Ghana and three improved varieties. Genetic diversity of these genotypes was studied using four primers, OPK-01, OPR-02, OPR-09 and OPJ-14. A total of 41 different bands were detected. Levels of polymorphic fragments detected by the four primers ranged from 90% to 100%. By pooling bands from individual accessions together, mean number of fragments per accession per primer ranged from 5.50±1.04 for the Improved cultivars to 7.00±0.71 for populations of landraces from Dormaa. Mean frequencies of fragments not detected by the primers for the accessions were 0.524±0.12, 0.460±0.12, 0.561±0.12 and 0.523±0.12 for landraces from Wenchi, Nkoranza, Dormaa Ahenkro, Asonafo and the Improved varieties, respectively. The grand mean frequency of individuals showing fragments not present in populations was 0.522±0.10. Genetic diversity estimates ranged from 0.290 to 0.425 (mean 0.352±0.05) for primer OPK-01, 0.001 to 0.381 (mean 0.309±0.06) for primer OPR-02, 0.335 to 0.344 (mean 0.283±0.04) for primer OPR-09 and 0.152 to 0.352 (mean 0.261±0.07) for primer OPJ-14. Within the accessions mean gene diversity estimates were 0.316±0.03, 0.293±0.09, 0.331±0.02, 0.322±0.07 and 0.247±0.03 for accessions from Wenchi, Nkoranza, Dormaa Ahenkro, Asonafo districts and the Improved varieties, respectively. Interpopulational genetic divergence ranged from 0.069 to 0.203 (mean 0.119±0.04). Rate of nucleotide substitution among the landraces was 9.8 per cent per site per year, while that for the Improved varieties was 15 per cent.

Diversity analysis of sweet potato ( Ipomoea batatas [L.] Lam) germplasm from Burkina Faso using morphological and simple sequence repeats markers

Collecting and characterizing plant material has been basic for crop improvement, and diversity has long been seen as vital for rational management and use of crops. Thirty (30) morphological characters and thirty (30) simple sequence repeat (SSR) markers were used to assess the diversity among 112 sweet potato (Ipomoea batatas [L.] Lam) cultivars in Burkina Faso and to develop a core collection. Eight morphological characters were able to differentiate the 112 accessions and to identify 11 duplicates while 28 SSR markers were more informative in discriminating the accessions and to identify five duplicates. The diversity assessment using the two approaches revealed high diversity with a coefficient of 0.73 using the phenotypic data, while moderate diversity with a coefficient of 0.49 was obtained using the SSR markers. These results show no correlation between the two approaches (with dissimilarity index of 0.95). A core collection was constituted using the SSR based data while the eight discriminative phenotypic descriptors will be used in the identification of cultivars.

Identification of Pro-vitamin A Cassava (Manihot esculenta Crantz) Varieties for Adaptation and Adoption through Participatory Research

In spite of diligent efforts by National Root Crops Research Institute (NRCRI) Umudike and International Institute of Tropical Agriculture (IITA) to make Nigeria the largest producer of cassava in the world, the adoption rate of elite cultivars by farmers is about 40% and that is unacceptable. In addition, all cassava cultivars presently grown in Nigeria are low in essential minerals, vitamins, and protein content, and high in cyanogenic content. Cassava with yellow roots contains elevated levels of β-carotene (pro-vitamin A), an essential nutrient, but they are not commonly grown in Nigeria. Because farmers select cultivars based on multiple criteria, participatory rural appraisal and selection are essential for a successful adoption of new improved varieties. A participatory rural appraisal (PRA) and sensory evaluation were conducted in Abia, Imo, and Ebonyi states of Nigeria to assess farmers’ preferences for pro-vitamin A cassava. Some of the farmer-preferred traits included high yield, early maturity, tolerance to pests and diseases, sweetness, high amount of dry matter (DM) content, easy peeling, marketable roots, and roots that keep long in the ground without decaying. High pro-vitamin A cassava cultivars TMS 01-1368, TMS 05-1636, and TMS 05-0473 were better than farmers’ cultivar NR 8082, because of their color, high premium price, nutritional value, texture, among others, and were selected for adoption.

Pesticide residues in fruits and vegetables in Ghana: a review

Pesticides are known to improve agriculture yield considerably leading to an increase in its application over the years. The use of pesticides has shown varying detrimental effects in humans as well as the environment. Presently, enough evidence is available to suggest their misuse and overuse in the last few decades in most developing nations primarily due to lack of education, endangering the lives of farmers as well as the entire population and environment. However, there is paucity of data especially over long durations in Ghana resulting in the absence of effective monitoring programs regarding pesticide application and subsequent contamination in fruits and vegetables. Therefore, this review discusses comprehensively pesticide type and use, importation, presence in fruits and vegetables, human exposure, and poisoning in Ghana. This is to alert the scientific community in Ghana of the need to further research into the potential implications of pesticide residues in food commodities in order to generate a comprehensive and reliable database which is key in drafting policies simultaneous with food regulation, suitable monitoring initiatives, assessment, and education to minimize their effects thereon.

Surveillance of pesticide residues in fruits and vegetables from Accra Metropolis markets, Ghana, 2010–2012: a case study in Sub-Saharan Africa

Monitoring of pesticide residues in food commodities of plant origin is part of the regular controls on food to safeguard consumer’s health. This study reports for the first time in Ghana a 3-year (2010–2012) monitoring of pesticide contamination of fruits and vegetables and their health implications. A total of 3483 samples were purchased in notable markets within Accra Metropolis and analysed for pesticide residues, employing the modified quick, easy, cheap, effective, rugged and safe analytical procedure. The results indicated that almost all the fruits and vegetables studied had residues above maximum residue limits (MRLs). The commodities with the greatest concentrations exceeding the European Union (EU) MRLs were long green beans (60.6%) and lettuce (57.1%) with watermelon (10%) and green pepper (8.6%) having the least. The relative occurrence of the pesticides was fenvalerate 11.3%, fenitrothion 5.6%, lambda-cyhalothrin 3.6%, dimethoate 3.2%, permethrin 2.7% and deltamethrin 2.2%. These results will serve as a baseline on which annual or other long-term studies could be compared with, thus emphasizing the need for continuous monitoring programmes to regulate trends of pesticide residues in fruits and vegetables to safeguard the consumers’ health.

Validation of QuEChERS method for the determination of 36 pesticide residues in fruits and vegetables from Ghana, using gas chromatography with electron capture and pulsed flame photometric detectors

In this study, “Quick, Easy, Cheap, Effective, Rugged and Safe” ‘QuEChERS’ method was modified for the determination of 36 pesticides fortified at (0.01–1.0) mg kg−1 in three vegetables and a fruit (lettuce, carrot, tomatoes and pineapples respectively) from Ghana. The method involved extraction with acetonitrile, phase separation with primary secondary amine and magnesium sulfate; the final injection solution was reconstituted in ethyl acetate. Organochlorine and synthetic pyrethroids residues were detected with electron capture detector whereas organophosphorus, pulsed flame photometric detector was used. The recoveries at different concentration levels (0.01, 0.1 and 1.0 mg kg−1) were in the range of 83% and 93% with relative standard deviation ranging from 2% to 10% (n = 5) and the coefficient of determination (R2) was greater than 0.99 for all the 36 pesticides. The method was successfully tested on 120 real samples from Accra markets and this proved to be useful for monitoring purposes particularly in laboratories that have no gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry.

Cocoa farming households in Ghana consider organic practices as climate smart and livelihoods enhancer

BackgroundSeveral state and non-state organizations are promoting organic agriculture as a climate smart option among cocoa farmers in the Ashanti region of Ghana. In this study, flora diversity and livelihoods position in organic and conventional farming were measured and compared. The experiment included 32 households with young plantations. Jaccard similarity, Shannon (H′) and Simpson (D) diversity indices were measured to assess species similarity, abundance, evenness and dominance. The sustainable livelihoods indicators were food security, income, vulnerability and well-being.ResultsThe results showed that the species are quite similar. The H′ index for organic farms was slightly higher (0.808) than that of conventional farms (0.762); the D index (0.051) for organic was better than the conventional (0.084). The organic farmers studied had better sustainable livelihoods outcomes than the conventional farmers.ConclusionSince organic farming has more biodiversity, farmers should be encouraged to practise it to improve livelihoods outcomes and enhance climate change mitigation.