Effects of moisture stress on germination and protein synthesis in root tips of cowpea (Vigna unguiculata L. Walp)

Unpigmented cowpea seeds, TVX 3236 (cream and brown) and IT81S-818 (white), were subjected to more stressful constant moisture conditions (-0.1 and -0.15 MPa) for 10 days. Germination was reduced from 90 to 43 and 60 per cent, respectively, compared to 90 per cent in those subjected to readily water availability (-0.0015 Mpa). These seeds germinated at -0.0015 MPa for shorter periods of 12 and 24 h compared to 48 h before imposition of stress (-0.15 MPa) for 7 days and showed more reduced final germination, after they had been returned to readily water availability for a further 7 days. However, pigmented seeds, TVX 2724-01F (brown) and IT82D-32 (dark-brown), showed very high germination between 90 and 100 per cent even under stress. The difference between these two groups of seeds, therefore, lies in their abilities to withstand water stress which was related to the differences in damage caused to their embryonic cells as shown by the extent of staining with 2, 3, 5 triphenyl tetrazolium chloride (TTC), and their abilities to synthesize protein after stress by incorporating L-4,5-3H leucine into their root tips.Les graines de dolique non pigmentées, TVX 3236 (crème et brune) et IT81S-818 (blanche), étaient exposées aux conditions d'humidité constantes plus stressantes (-0.1 et -0.15 MPa) pour 10 jours; Ces graines ont subi de germination réduite respectivement de 90 à 43 et 60% comparé à 90% en celles qui étaient exposées à l'eau facilement disponible (-0.0015 Mpa). Ces graines germinaient à -0.0015 MPa pour des périodes plus courtes de 12 et 24 h comparées à 48 h avant l'imposition de pression (-0.15 MPa) pour 7 jours et montraient de germination final plus réduite après avoir été remises à l'eau facilement disponible pour 7 jours. Les graines pigmentées TVX 2724-01F (brune) et IT82D-32 (brune-foncée), montraient cependant de germination très élevée entre 90 et 100% même sous les conditions de pression. La différence entre ces deux groupes de graines réside donc dans leurs capacités de résister à la pression d'eau qui était liée aux différences en dégats causés aux cellules embryonnaires comme révélé par l'ampleur de tacher avec 2, 3, 5 chlorure de triphényl tétrazolium (CTT), et leurs capacités de produire synthétiquement la protéiene après la pression par l'incorporation de L-[4, 5-3 H] leucine dans les bouts de racine. Ghana Journal of Agricultural Science Vol. 39 (2) 2006: pp. 165-17

Effects of farmers\' seed source on maize seed quality and crop productivity

Although farmer-saved seeds constitute about 90 per cent of maize seeds planted annually, their effects on crop performance are not well known. This study determined the seed quality and field performance of farmer-saved seeds of the most popular quality protein maize (QPM) variety, Obatanpa, compared to the certified seed of the same variety. Seed samples collected from four locations (Kwadaso, Ejura, Nkoranzah and Wenchi) showed higher percentage complete vital staining of embryos using 2, 3, 5 triphenyl tetrazolium chloride (TTC) and higher 1000-seed weight in certified seeds, indicating high vigour and complete seed development. Whereas germinating seedlings of the certified seeds did not show any fungal growth, farmersaved seeds showed profuse fungal development and stunting. Seedling counts showed 9 and 21 per cent reduction in certified and farmer-saved seeds, respectively; but plant counts before harvest showed 12 and 23 per cent reduction. Plants originating from certified seeds flowered at the predetermined date of 55 days, but the farmer-saved seeds flowered about a day or two later owing to reduced vigour. Lodging was less in plants originating from certified seeds, particularly in the trial planted at Ejura (transition zone) compared to Kwadaso (forest zone). The advantages of certified seeds reflected on increased grain yield, which was about 1.2 t ha-1, equal to ¢1,100,000.00 ($110) ha-1 or 47 per cent increases over the farmer-saved seeds. The study, therefore, showed the importance of certified seeds in increasing maize productivity and farmers' incomes. Bien que la semence gardée par l'agriculteur constitue environ 90 pour cent de graines de maïs semées annuellement, ses effets sur le rendement de culture ne sont pas bien connus. Une étude était entreprise pour déterminer la qualité de graine et le rendement sur le terrain de semence gardé par l'agriculteur de la variété la plus populaire du maïs protéique de qualité (MPQ), Obatanpa, comparé à la graine certifiée de la même variété. Les échantillons de graine recueillis de quatre emplacements (Wenchi, Nkoranzah, Ejura et Kwadaso) montraient un pourcentage plus élevé de tâches embryonnaires vitales et complétes, appliquant 2,3,5 chlorure triphényl tétrazolium (CTT), ainsi qu'un poids de 1000 graines plus élevées en semence certifiée, indiquant une vigueur élevée et un développement complet de graine. Tandis que les semis germant de semences certifiées n'ont pas montré aucune croissance fongique, les semences gardés par les agriculteurs montraient un développement fongique abondant et retardé. Les comptes de semis montraient 9 et 21 pour cent de réduction respectivement en semence certifiée et en semence gardée par l'agriculteur, tandis que les comptes de plante avant la moisson montraient 12 et 23 pour cent de réduction. Les plantes poussant de semences certifiées fleurissaient à la date déterminée de 55 jours, tandis que les semences gardées par l'agriculteur fleurissaient environ un ou deux jours plus tard à cause de vigueur réduite. Moins de la verse se produisaient chez les plantes poussant de semences certifiées, surtout dans les cultures d'essai plantées à Ejura (zone de transition) comparé à l'essai de Kwadaso (zone de forêt). Les avantages de semences certifiées se traduisaient dans l'augmentation de rendement de graine, qui étaient environ 1.2 t/ha, un équivalent de ¢1,100,000.00 ($110)/ha ou 47 pour cent d'augmentation par rapport aux semences gardées par l'agriculteur. L'étude, par conséquent, démontraient l'importance de semences certifiées à l'augmentation de la productivité de maïs et les revenus d'agriculteurs. Ghana Journal of Agricultural Science Vol. 40 (1) 2007: pp. 105-11

Re-Evaluation of Yam Mosaic Virus (YMV) Detection Methods

Accurate and timely detection is vital for mitigation of tuber yield losses resulting from yam mosaic virus (YMV) infection on yam, a major food security crop in West Africa. The observation, from our previous studies, that the triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA), the most commonly used detection method for YMV, detected the virus in significantly less leaf samples than immunocapture reverse transcription polymerase chain reaction (IC-RT-PCR) necessitated a re-evaluation of YMV detection methods. In the present study, eighteen previously tested YMV positive leaf samples from Benin and Ghana were re-tested using TAS-ELISA, Protein A-sandwich (PAS) ELISA and IC-RT-PCR. Three sap dilutions, 1/10, 1/50 and 1/100, were tested for each sample. Both at 1/10 and 1/50 dilutions, PAS-ELISA and IC-RT-PCR detected YMV in 11 (61.1%) and 12 (66.7%) of the leaves respectively. Virus detection by PAS-ELISA reduced to 50% at 1/100 sap dilution and increased to 77.8% in IC-RT-PCR. YMV detection by TAS-ELISA varied between 38.9% and 16.7% at 1/10 and 1/100 dilutions respectively. These results indicate a deficiency in the use of TAS-ELISA as a sole YMV certification method since the detecting monoclonal antibody used in this assay may be strain specific. The use of PAS-ELISA at a 1/10 sap dilution is suggested for YMV detection where the facilities for molecular detection are unavailabl

Palaeoclimatic Control on the Composition of Palaeozoic Shales from Southern Ghana, West Africa

The Late Ordovician to Early Cretaceous Sekondian Group of southern Ghana is made up of seven major sedimentary formations. One important feature of the Sekondian Group is the abundance of fairly fresh plagioclase in the lowest two formations, i.e., the Ajua Shale and Elmina Sandstone, and at the uppermost formation (i.e., Essikado Sandstone); but a virtual absence throughout the rest of the Group. The basal part of the Sekondian Group has been interpreted as of glacial origin whereas the upper formations are thought to have formed in a warmer stage. The abundant plagioclase in the lowest two formations could, therefore, be due to less pervasive chemical weathering rather than erosion of a distinct source. In this paper, geochemical data for fine-grained sedimentary rocks of the Ajua Shale and the Takoradi Shale (that overlie the Elmina Sandstone) formations are used to investigate the influence of palaeoweathering on the composition of the Sekondian Group.The concentrations of the transition trace metals Cr, Ni, V, and Cu, and Cr/V-, Zr/Y-, and Ba/Co-ratios are similar in the samples from both formations and suggest that they were largely derived from the granitoids that intrude the Birimian supracrastal rocks. However, the Takoradi Shale samples are enriched in Rb, Cs, Th, U, and Nb relative to the Ajua Shale samples, and this may be related to differences in the degree of weathering in the source rocks. The Takoradi Shale samples are characterized by high chemical index of alteration (CIA) values and Rb/Sr ratios (CIA > 75; Rb/Sr > 1) indicating high degrees of weathering of their source rocks. In contrast, the Ajua Shale samples have low CIA values and Rb/Sr ratios (CIA < 62; Rb/Sr < 0.5) that indicate low degrees of weathering of their source. The tectonic setting at the time of deposition of both formations was passive margin suggesting that the change in paleoclimatic conditions rather than erosion rates played a more dominant role in the observed compositional changes in these shales

Enhancing crop productivity through community-based seed multiplication system

Improved quality seeds out-yield farmers' saved seeds significantly. However, the limited availability of such seeds through the conventional seed supply system is due to socio-economic factors and inadequacy of skilled personnel and infrastructure. A community-based seed multiplication system was, therefore, adopted and small seed stocks of soybean, cowpea and yam were distributed to farmer groups in the rural communities in northern Ghana, northern Nigeria and central Togo, respectively, between 1996 and 1999 for further multiplication. An impact assessment after 4 years showed a significant ease of farmers' access to improved seeds and development of linkages with pesticide dealers, credit sources, and extension services as a result of opting for this system. Quality of farmers' saved seeds had improved and farmers' yield had increased over 90 per cent. Extra incomes earned were used to purchase household items, and part invested in transport businesses and rearing of small ruminants as well as in human capital such as paying children's school fees and family hospital bills and meeting other social responsibilities. This system was, therefore, effective in diffusing improved seeds and associated technologies and services to many more farmers and communities within a very short time to improve their socio-economic status.Les graines de qualité améliorée dépassaient considérablement en rendement les graines gardées par les agriculteurs. Cependant, la disponibilité de telles graines par le système conventionnel de provision de graine est limitée en raison de facteurs socio-économiques, l'insuffisance de personnel qualifié et l'infrastructure. Un système de multiplication de graine basé à la communauté était donc adopté et une petite quantité de stocks de graine de soja, de dolique et d'igname étaient distribués aux groupes d'agriculteurs dans les communautés rurales dans le nord du Ghana, le nord du Nigéria et le centre du Togo respectivement entre les années 1996 et 1999 pour de multiplication davantage. L'évaluation d'impact entreprise après quatre années montrait une aisance considérable avec laquelle les agriculteurs avaient accès aux graines améliorées et aux liens de développement avec les marchands de pesticide, les lignes de crédit et les services de vulgarisation agricole à la suite d' opter pour ce système. La qualité de graines gardées par les agriculteurs avait amélioré et les rendements d'agriculteurs avaient augmenté plus de 90%. Les suppléments de revenus gagnés étaient dépensés pour les articles ménagers, et une partie du revenun était investie en entreprises de transport et en élévage de petits ruminants ainsi qu'en ressources humaines telles que le paiement de frais de scolarité de la jeunesse, les factures hospitalières et pour régler d'autres responsabilités sociales. Ce système était donc efficace pour la distribution de graines améliorées et la vulgarisation de services et de technologies liées à l'agriculture à beaucoup plus d'agriculteurs et aux communautés dans très peu de temps pour améliorer leur situation socio-économique. Ghana Journal of Agricultural Science Vol. 39 (2) 2006: pp. 181-18

Consumption trends of white cassava and consumer perceptions of yellow cassava in Ghana

Open Access JournalVitamin A deficiency has been one of the major nutritional problems for many countries where cassava is eaten as a major source of energy. In an attempt to help reduce the incidence of vitamin A deficiency, bio-fortified cassava which contains more pro-vitamin A carotenoids than the white cassava, has been introduced to such areas. This study therefore endeavored to find out how often Ghanaians ate cassava and its products, as well as what Ghanaian consumers knew about bio-fortified cassava and their willingness to consume it. A survey was done between the month of January and March using 287 participants in the Greater Accra Region of Ghana which gathered information on their demographics, and their frequencies of the consumption of cassava and its products. Data on the knowledge of the participants on yellow flesh cassava, and their willingness to accept it were also gathered. Logistic regression was used to determine the relationship between some demographic characteristics and knowledge and ‘willingness-to-accept’ biofortified cassava. The cassava product which was mostly consumed by the participants was gari. Sixty-three percent of the participants had no knowledge of bio-fortified cassava. About half of them were willing to accept the biofortified cassava, and more than half of the participants perceived that yellow cassava could be used for some white cassava products. Providing nutritional information and sensitizing consumers on the benefits of biofortified cassava can enhance its consumption in Ghana

Housing attributes and relative house prices in Ghana

Purpose The study of house prices has become more relevant in recent times after the global financial crisis. Using a housing data set from three regions of Ghana (collated from real estate agents), the purpose of this paper is to estimate the relative importance of housing attributes to house prices. Design/methodology/approach The hedonic regression analysis conducted indicates that location is the most powerful determinant of house prices. Other relevant factors are the number of bedrooms, the number of floors, the total floor area, land size, age of the house and luxury finishing. Findings The implications of these results are many. Policy wise, the study provides an evidence-based empirical study that supports the need for better urban planning to improve communities, which in turn is associated with house price appreciations. Homeowners, investors and creditors, particularly mortgage lenders could be the immediate beneficiaries. Drawing on this, improved urban planning could mitigate strategic defaults that results from house prices falling below mortgage loan balances. This is important for financial market stability. Originality/value The paper provides a comprehensive and unique understanding of the hedonic determinants of house prices in Ghana. Future studies could examine the effect of location upon mortgage lending in Ghana

Agronomic potentials of quality protein maize hybrids developed in Ghana

A quality protein maize (QPM) hybrid programme was started in 1991 to develop and promote high and stableyielding QPM hybrids to increase production of nutritionally superior maize varieties in Ghana. Six 3- way QPM hybrids developed from inbred lines originating from germplasm of the International Centre for Maize and Wheat Improvement (CIMMYT) were evaluated on research stations and in farmers\' fields in Ghana from 1995 to 1996. In the on-station evaluations, grain yields across 10 sites in both years averaged 6.0 ton ha-1 for the three hybrids (GH132-28, GH110-5 and GH2328-88), 5.22 ton ha-1 for Obatanpa, and 3.60 ton ha-1 for the local maize variety. In farmers\' fields, data from over 50 farm sites in 1995 and 1996 showed mean yields of 4.95 ton ha-1 for the three hybrids, and 4.28 ton ha-1 for Obatanpa compared to 3.59 ton ha-1 for farmers\' varieties. On the average, the hybrids were similar to Obatanpa in days to 50 per cent silking, but were shorter in plant height and ear placement. Consumer preference tests showed that the three hybrids were rated similar to the local variety in popular traditional food preparations such as ‘kenkey\' and ‘tuo zafi\'. In 1997, the National Variety Release Committee approved the release of GH132-28, GH110-5, and GH2328-88 under the local names Dadaba, Mamaba, and CIDA-ba, respectively. These hybrids are recommended for planting in all the major agro-ecologies to boost maize production in Ghana.Les variétés de maïs hybride (Zea mays L.) dont les plus sésirées que les variétés de pollinisation libre à cause de leur uniformté et leurs potentiels de rendement plus élevés. Pour augmenter la production de variétés de maïs nutritionnellement supérieures au Ghana, I\'Institut de Recherche de Cultures a mis en place un programme hybrid de maïs protéique de qualité (MPQ) en 1991 pour développer et promouvoir des hybrides de MPQ de rendement élevés et stable. Six hybrids en trois de MPQ développés d\'issu de la même souch provenant de germeplasmes de CIMMYT (Centre International pour I\'amélioration de maïs et de blé) étaient évalués aux stations de recherches et aux champs d\'agriculteurs au Ghana de 1995 à 1996. Dans les évaluations sur place, les rendements de grain à travers 10 sites dans les deux années ont atteint la moyenne de 6.0 ton ha-1 pour les trois hybrids (GH132-28, GH110-5 et GH2328-88), 5.22 ton ha-1 pour \'Obatanpa\' et 3.60 ton ha-1 pour la variétés de maïs local. Sur les champs d\'agriculteurs des données de plus que 50 sites de champs en 1995 et 1996 montraient les rendements moyens de 4.95 ton ha-1 pour les trois hybrids et 4.28 ton ha-1 pour les \'Obatanpa\' comparées à 3.59 ton ha-1 pour les variétés d\'agriculteurs. En moyenne, les hybrides étaient semblables à \'Obatanpa\' en jours jusqu à 50% d\'apparition de soie maïs étaient plus courtes en taille de plante et en placement d\'épi. Les essais de préférence de consommateur montraient que les trios hybrides étaient évalués semblables à la variété locale dans les préparations de nouriture traditionnelle populaire telle que \'kenkey\' et \'tuo zafi\'. En 1997, le comité pour la mise en vente de Variété Nationale a approuvé la mise en vente de GH132-28, GH110-5 et GH2328-88 sous les noms locaux respectifs de Dadaba, Mamaba, et CIDA-ba. Ce hybrides sont recommandés pour la popultion dans toutes les agroéclogies majeures pour stimuler la production de maïs au Ghana. Ghana Journal of Agricultural Science Vol. 40 (1) 2007: pp. 81-8

Yam improvement for income and food security in West Africa: Effectiveness of a multi-disciplinary and multi-institutional team-work

The overall goal of the five year project “Yam Improvement for Income and Food Security in West Africa” (YIIFSWA) funded by the Bill and Melinda Gates Foundation and led by the International Institute of Tropical Agriculture, Ibadan, Nigeria was to: (a) increase yam productivity by 40% for 2,00,000 smallholder yam farmers in Ghana and Nigeria and (b) deliver key global good research products that will contribute to the 10-year overall vision to sustainably double incomes from yams for 3 million smallholder yam farming families and contribute to ensuring food security for producers and consumers. Implemented by scientists of twenty partner specialized organizations, comprising research institutes, Universities, governmental and non-governmental organizations, YIIFSWA has impacted yam value chain stakeholders through research and development interventions. The significant contributions made in the project during the past 18 months’ period are discussed in this paper. These include: a baseline survey conducted in key yam growing areas in Ghana and Nigeria, training of yam producers on adapted yam minisett technique and production of seed yam, undertaking in depth value chain assessments, developing the capacity of Farmers Organizations (FOs) by linking them to service providers (SPs), participatory evaluation of new yam genotypes, successful development of yam virus diseases diagnostics and development of novel techniques for high ratio yam propagation such as aeroponics and bioreactors