Browsing by Author "Yeboah, M."
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Item Breeding for Drought Tolerance in Cowpea [Vigna Unguiculata (L.) Walp.] Using Marker Assisted Backcrossing(University of Ghana, 2014-12) Batieno, T. B. J.; Danquah, E.Y.; Ofori, K.; Yeboah, M.; Drabo, I.; University of Ghana, College of Basic and Applied Sciences , School of Agriculture , Department of Crop ScienceThe potential of cowpea to address food security in Burkina Faso in particular is well established. However, there is limited information on drought tolerance and diversity in the germplasm in Burkina Faso and farmers’ perceptions on the effects of drought and their varietal preferences are not known. The present study was, therefore, conducted to: (1) identify farmers’ perceptions on the impact of drought on cowpea production and identify their preferences regarding cultivars and traits, (2) identify drought tolerant varieties in cowpea germplasm, (3) determine single nucleotide polymorphisms (SNPs) based genetic diversity in the cowpea germplasm, and (4) implement marker-assisted backcrossing to transfer yield and stay-green QTLs into Moussa local, a farmer preferred landrace. A participatory rural appraisal (PRA) was conducted to identify farmers’ perceptions on the impact of drought on cowpea production. This study established that farmers have a deep knowledge about cowpea production constraints. Limited access to seed of improved variety was ranked as the most important constraint in all the areas where the study was conducted. Drought was classified among the four most important constraints to cowpea production in the three districts where the PRA was conducted. The preferred grain traits for all regions were white colour, large seeds with a rough texture for food and market purposes, except for the northern region where brown grain colour was preferred for food. The identification of drought-tolerant varieties in cowpea germplasm through field screening of fifty genotypes and the use of selection indices revealed wide genotypic variability among the tested germplasm. Biplot displays indicated that the genotypes could be grouped into four categories according to their drought tolerance and yielding ability as indicated below: high yielding-drought tolerant (group A), high yielding-drought susceptible (group B), low yielding-drought tolerant (group C), and low yielding-drought susceptible (group D). Genotypes like Djouroum local, KVx404-8-1, IT98K-1111-1, Gorom local, CB27, IT93K-693-2, Mouride, and KVx61-1 were clustered in group A, that is they were high yielding and drought tolerant. The stress tolerance index was the best criterion for assessing genotypes for variability to drought tolerance because it enabled the identification of high yielding and drought tolerant genotypes. Genetic diversity was assessed using 181 SNP markers on 50 cowpea lines. The phylogenetic pattern of this germplam revealed seven clusters. The lines were almost grouped based on their geographical origin, and the breeding background. Thus, materials which originated from Burkina Faso were clustered in the same group while those from IITA/Nigeria were also almost all clustered in the same group. The genetic distance was low (≤0.29) suggesting a narrow genetic base in the cowpea germplasm used in this study. SNPs were efficient in the study of the diversity and a core collection of 20 lines was generated for further use in the breeding program. Marker-assisted backcrossing (MABC) was used to transfer QTLs for yield under drought and stay-green into Moussa local, a farmer preferred landrace. Two backcrosses assisted by SNP markers in foreground and background selections were sufficient to select for QTLs presence and to recover the background of Moussa local, the recurrent parent. The BC3F1s were selfed and six BC3F2s were evaluated for preliminary yield under drought stress and non-stress conditions. Out of the six, three MABC selected lines were promising and yielded better than the check and the parents. From these recombinant lines, several high yielding lines are likely to be developed for release in the near future. Most of them could be used in intercropping which will make great impact on cowpea production in Burkina Faso. In general, potential parents for genetic improvement for yield and drought tolerance were identified. However, further studies for assessing yield stability of cowpea genotypes are necessary and could be achieved by including more seasons and sites to get a better understanding of the genotype × environment interaction and yield stability of cowpea in Burkina Faso for all the materials identified including the MABC lines. Key words: Burkina Faso, farmers, drought tolerance, cowpea, genotypes, genetic distance, SNPs, marker-assisted backcrossing, Participatory Rural Appraisal.Item Diversity in 113 cowpea [Vigna unguiculata (L) Walp] accessions assessed with 458 SNP markers(2014-09-20) Egbadzor, K.F.; Ofori, K.; Yeboah, M.; Aboagye, L.M.; Opoku-Agyeman, M.O.; Danquah, E.Y.; Offei, S.K.Abstract Single Nucleotide Polymorphism (SNP) markers were used in characterization of 113 cowpea accessions comprising of 108 from Ghana and 5 from abroad. Leaf tissues from plants cultivated at the University of Ghana were genotyped at KBioscience in the United Kingdom. Data was generated for 477 SNPs, out of which 458 revealed polymorphism. The results were used to analyze genetic dissimilarity among the accessions using Darwin 5 software. The markers discriminated among all of the cowpea accessions and the dissimilarity values which ranged from 0.006 to 0.63 were used for factorial plot. Unexpected high levels of heterozygosity were observed on some of the accessions. Accessions known to be closely related clustered together in a dendrogram drawn with WPGMA method. A maximum length sub-tree which comprised of 48 core accessions was constructed. The software package structure was used to separate accessions into three groups, and the programme correctly identified varieties that were known hybrids. The hybrids were those accessions with numerous heterozygous loci. The structure plot showed closely related accessions with similar genome patterns. The SNP markers were more efficient in discriminating among the cowpea germplasm than morphological, seed protein polymorphism and simple sequence repeat studies reported earlier on the same collection.Item Diversity in 113 cowpea [Vigna unguiculata (L) Walp] accessions assessed with 458 SNP markers(SpringerPlus, 2014-09) Egbadzor, K.F.; Ofori, K.; Yeboah, M.; Aboagye, L.M.; Opoku-Agyeman, M.O.; Danquah, E.Y.; Offei, S.K.Single Nucleotide Polymorphism (SNP) markers were used in characterization of 113 cowpea accessions comprising of 108 from Ghana and 5 from abroad. Leaf tissues from plants cultivated at the University of Ghana were genotyped at KBioscience in the United Kingdom. Data was generated for 477 SNPs, out of which 458 revealed polymorphism. The results were used to analyze genetic dissimilarity among the accessions using Darwin 5 software. The markers discriminated among all of the cowpea accessions and the dissimilarity values which ranged from 0.006 to 0.63 were used for factorial plot. Unexpected high levels of heterozygosity were observed on some of the accessions. Accessions known to be closely related clustered together in a dendrogram drawn with WPGMA method. A maximum length sub-tree which comprised of 48 core accessions was constructed. The software package structure was used to separate accessions into three groups, and the programme correctly identified varieties that were known hybrids. The hybrids were those accessions with numerous heterozygous loci. The structure plot showed closely related accessions with similar genome patterns. The SNP markers were more efficient in discriminating among the cowpea germplasm than morphological, seed protein polymorphism and simple sequence repeat studies reported earlier on the same collection. © 2014, Egbadzor et al.; licensee Springer.Item Farmer participation in selection within segregating populations of cowpea in Volta Region, Ghana(2015-11-01) Egbadzor, K.F.; Offei, S.K.; Danquah, E.Y.; Kotey, D.A.; Gamedoagbao, D.K.; Dadoza, M.; Yeboah, M.; Ofori, K.Abstract Background Participatory plant breeding leads to early adoption of a newly released variety as farmers would be aware of whatever advantage it might have over prior existing ones as early as possible. Cowpea farmers around Ohawu in the Volta Region of Ghana where the crop is one of the most important cash crops had no variety specifically developed for their environment. This research followed farmers’ interest identified earlier for the development of varieties with preferred consumer traits. Methods Farmers were chosen from 25 communities within the cowpea growing area by the help of agricultural extension officers. Fifty farmers including 25 males and females each, 7 scientists and 15 other persons with different backgrounds were involved in the selection exercise. The final plants selected were based on the total number of participants’ endorsement and analysis of variance for their seed size. Results Selections were made from six F3 populations with parents of various unique traits obtained from Botswana, Ghana, Nigeria, Senegal, or United States of America. Four most liked cowpea plants from each of the six populations were selected to be advanced and tried in multi-locations towards probable release. Conclusions Participants were very enthused with the selection exercise hoping of seeing some of their selections resulting into varieties. Farmers were interested in selecting plants with long multiple pods and early maturing. The exercise was educative for all participants.Item Farmer participation in selection within segregating populations of cowpea in Volta Region, Ghana(Agriculture & Food Security, 2015-11) Egbadzor, K.F.; Offei, S.K.; Danquah, E.Y.; Kotey, D.A.; Gamedoagbao, D.K.; Dadoza, M.; Yeboah, M.; Ofori, K.Background Participatory plant breeding leads to early adoption of a newly released variety as farmers would be aware of whatever advantage it might have over prior existing ones as early as possible. Cowpea farmers around Ohawu in the Volta Region of Ghana where the crop is one of the most important cash crops had no variety specifically developed for their environment. This research followed farmers’ interest identified earlier for the development of varieties with preferred consumer traits. Methods Farmers were chosen from 25 communities within the cowpea growing area by the help of agricultural extension officers. Fifty farmers including 25 males and females each, 7 scientists and 15 other persons with different backgrounds were involved in the selection exercise. The final plants selected were based on the total number of participants’ endorsement and analysis of variance for their seed size. Results Selections were made from six F3 populations with parents of various unique traits obtained from Botswana, Ghana, Nigeria, Senegal, or United States of America. Four most liked cowpea plants from each of the six populations were selected to be advanced and tried in multi-locations towards probable release. Conclusions Participants were very enthused with the selection exercise hoping of seeing some of their selections resulting into varieties. Farmers were interested in selecting plants with long multiple pods and early maturing. The exercise was educative for all participants.Item Survival of Mushrooms and Termites Upon Pesticide Exposure in the Cocoa Agro-ecosystem(JOURNAL OF TROPICAL LIFE SCIENCE, 2023) Asare, E.K.; Avicor, S.W.; Bukari, Y.; Amoako-Attah, I.; Agyare, S.; Yeboah, M.; Wiafe-Kwagyan, M.Pesticides have become integral parts of cocoa cultivation for the management of in sect pests and fungal pathogens which cause significant damage to the crop. However, continuous pesticide usage in the cocoa agro-ecosystem is of concern due to perceived adverse effects on non-target organisms. In this study, mushrooms and associated ter mites were used to elucidate the possible effect of fungicides and insecticides on non target organisms in the cocoa agro-ecosystem. The vegetative phase of Pleurotus sa jor-caju (Oyster mushroom), Volvariella volvacea (Paddy straw mushroom), Termi tomyces globulus, and Termitomyces robustus (Termite mushrooms) were subjected to concentrations of commercially formulated fungicides (metalaxyl 12 % + copper (I) oxide 60 % and cupric hydroxide 77 %) and insecticides (imidacloprid 20 % and bifenthrin 2.7 %) to observe their growth rates on Potato Dextrose Agar (PDA). Worker termites, Macrotermes bellicosus, were also exposed to the pesticides in Petri dishes for 24 h to observe their mortality. The manufacturer’s recommended concen tration of 245 ppm for bifenthrin completely inhibited mycelial growth of all the mushrooms and caused 100% mortality of termites. At 0.0245 ppm, the insecticide caused 60% mortality of termites, but it had no inhibitory effect on the mushrooms. Except for P. sajor-caju, mycelial growth of all the other mushrooms was completely inhibited by metalaxyl + copper (I) oxide at the manufacturer’s recommended con centration of 2400 ppm. However, mycelial growth rate of the mushrooms at 0.24 ppm of the fungicide was similar to the control plates. Although the recommended concentrations of the pesticides inhibited mushroom activity under controlled condi tions, mushroom survival in the cocoa agro-ecosystem amidst pesticides could be due to diluted pesticide concentrations that result in the soil after application which is usu ally directed at the pods, trunk, and foliage