African Crop Science Journal <p>The <em>African Crop Science Journal,</em> a quarterly publication, publishes original research papers dealing with all aspects of crop agronomy, production, genetics and breeding, germplasm, crop protection, post harvest systems and utilisation, agro-forestry, crop-animal interactions, information science, environmental science and soil science. It also publishes authoritative reviews on crop science and environmental issues by invitation. It is bilingual, publishing in either English or French. </p><p>Other websites related to the journal include: <a title="" href="" target="_blank"></a></p> en-US Copyright for articles published in this journal is retained by the journal. (Dr. J.S. Tenywa) (Editor) Fri, 26 Feb 2021 08:08:10 +0000 OJS 60 Olfactory responses of Sitophilus zeamais L. to bushmint leaf powder and methanol extract on stored maize <p>Bushmint (<em>Hyptis suaveolens</em> Poit) is a weed with pesticidal properties that have been explored in managing pests of agricultural and medicinal importance. The objective of this study was to evaluate the repellence ability of Hyptis suaveolens to prevent infestation of stored maize grain seed. The study involved evaluation of the olfactory responses of adult weevil to maize (<em>Zea mays</em> L.) grains treated with 5, 10, 15 and 20% concentrations of leaf powder (LP) and methanol extract (ME) of<em> Hyptis suaveolens</em> in the laboratory, with a static air four-chamber olfactometer. Also, the insecticidal effects of the substances on adult mortality and oviposition on maize grains treated with LP and ME were determined in a completely randomised design, with four replicates. The number of weevils in ME chambers decreased with increase in concentration of extracts; while the LP chambers had consistently fewer weevils with numbers, ranging from 2.5 to 3.75. Adult mortality in maize treated with LP was the least and varied between 0.00 (15% concentration) and 2.54% (20% concentration). Maize grains with ME caused significant mortalities that ranged from 65.50% at 15% concentration to 94.92% at 10% concentration. More eggs (3.5 to 5.75) were laid on maize with LP compared with ME treated maize. Generally, ME was richer in phytochemicals than LP. Hyptis suaveolens repellence manifested more in the form of LP than as ME; though ME caused more adult mortality and reduced oviposition than LP.</p> A.M. Noudegbessi, O.Y. Alabi, R. Sikirou Copyright (c) Effets de la fumure minerale et des predateurs sur le niveau d’infestation du cotonnier par le puceron (Homoptera : Aphididae) au Togo <p>Dans la perspective de contribuer à l’élaboration d’une stratégie de gestion intégrée du puceron de cotonnier <em>Aphis gossypii,</em> les tests de l’effet de la fumure minérale et des prédateurs sur la variation des niveaux de population de ce dernier ont été étudiés. La collecte des données a été réalisée par un suivi à chaque trois jour sur plants de cotonnier (<em>Gossypium hirsutum </em>L.) installé en parcelles expérimentales à la Station d’ Expérimentation Agronomique de l’Université de Lomé. Les résultats de la fluctuation de population d’Aphis gossypii ont révélé deux pics de pullulation durant le cycle du cotonnier. Le premier pic de la petite période de pullulation au 46ème jour après semis (jas) est moins important numériquement. Le second pic de la grande période de pullulation au 86ème jas est numériquement plus important et cause des dégâts considérables aux cotonniers. Les infestations et les niveaux de variation de populations au cours du cycle de la culture cotonnière sont très dépendants de la dose de fumure minérale appliquée La présence et le développement des prédateurs ont corrélé positivement avec le niveau d’infestation des plants par le puceron sans avoir un effet régulateur remarquable de la population de ce dernier.</p> P.K. Akantetou, P. Tozoou, M.E. Bokobana, N.A. Nadio, P. Kilimou, K. Koba, W. Poutouli , K. Sanda Copyright (c) Evaluation of tigernut accessions in Ghana for proximate and mineral composition <p>Tigernut (<em>Cyperus esculentus</em> L.) is a nutritious, yet underutilised crop in Ghana. The objective of this study was to characterise Ghanaian tigernut accessions for proximate and mineral composition, as a guide for breeders for varietal development. Field and laboratory studies were conducted on 24 tigernut accessions from major growing areas of Ghana. The accessions were cultivated during the minor the growing season (September - November), at the Multipurpose Nursery of the University of Education, Winneba, Asante Mampong in Ghana. The nuts were analysed for proximate (carbohydrate, energy, moisture, ether extract, crude fiber, crude protein and ash) and mineral (potassium, phosphorus and calcium) composition. There were significant (P&lt;0.05) differences among accessions for all traits studied. Accessions were clustered in a dendrogram by colour and geographical origin and PC1 and PC2 explained more than 80% of the total variations among the accessions, with carbohydrate and energy being the major contributors to the total variation. Accessions DY, BKB, KAB, TPY, CCY, WY2 and WY1, which recorded high levels of proximate and mineral compositions, may be considered for breeding programmes to provide high nutrient varieties of tigernut in Ghana.</p> E.F. Donkor, D. Nyadanu, H.K. Dapaah Copyright (c) Protocol optimisation for micropropagation of Ethiopian yam <p>Yam (<em>Dioscorea</em> spp.) is a monocotyledonous tuber forming tropical vine, which belongs to the family Dioscoreaceae, and genus Dioscorea. Yam is well known for medicinal properties, as well as nutritional values. Conventional propagation of yam is limited by low propagation rates; hence,<em> in vitro</em> propagation provides the best alternative to overcome such limitations. The objective of this study was to optimise a protocol for in vitro micro-propagation of Ethiopian yam (<em>D. alata</em>, bulcha variety). Explants were obtained from young leaves of bulcha variety, and sterilised using different concentrations of NaOCl, for different time exposures. Sodium hypochlorite (1%) at 15 minutes exposure time, showed 100% survival of explants. The combination of 0.5 BAP with 1mgl-1 NAA was the best concentration for shoot induction. For shoot multiplication, BAP at 1.5 mg l-1 gave the highest shoots per explants (7.28±0.07), with shoot length of 8.72±0.43 cm. MS medium with 2.0 mg l-1 NAA and 1.5 mg l-1 IBA gave the highest rooting percentage and root number (10.6±0.44), with a root length of 13.80±0.44. In vitro acclimatised plantlets,which were transferred to a greenhouse for hardening, had 90% survival rate on soil medium. Thus, for micropropagation of bulcha yam variety, MS + 1.5 mg l-1 and MS plus 2.0 mg l-1 NAA + 1.5 mg l-1 IBA is the best phytohormonal combination for shoot multiplication and invitro rooting, respectively.</p> D. Birhan, D. Obssi, K. Mulugeta Copyright (c) Morphological characteristics and genetic diversity of Ethiopian sesame genotypes <p>Sesame (<em>Sesamum indicum</em> L.) is produced worldwide, although more than 96% of the world sesame seed is produced in Africa and Asia. The objective of this study was to determine morphological properties and identify the genetic diversity of cultivated sesame genotypes grown in different parts of Ethiopia. Three hundred sesame genotypes collected from diverse ecologies of Ethiopia and introduced from different African and Asian countries, were used in this study. Genotypes showed wide variability for most morphological traits, except for plant growth type, leaf glands, anther filament colour, anther connective tip gland, and anthocyanin colouration of the capsule. Genetic divergence using Mahalanobis D2 statistics was computed, and the genotype lines were grouped into six different clusters. Clustering was not associated with the geographical distribution; instead genotypes were grouped mainly based on morphological differences. The lowest divergence was noticed between cluster I and V (10.06). Maximum inter-cluster distance was observed between clusters IV and VI (D2 =342.56, followed by clusters I and VI (D2 =217.9783), and III with IV (D2 =190.8707). Maximum genetic recombination and variation in the subsequent generation, is expected from crosses that involve parents from the clusters characterised by maximum distances. Thus, maximum distances or varation could maximise opportunities for transgressive segregation, since unrelated genotypes would contribute unique desirable alleles at different loci.</p> T. Tesfaye, K. Tesfaye, G. Keneni, T. Alemu Copyright (c) Distribution of potato viruses in Uganda <p>Viral diseases are among the major factors affecting potato (<em>Solanum tuberosum</em> L.) production in Uganda. Knowledge of the types of viruses and their distribution levels in the country is vital for targeting sound management strategies. The objective of this study was to assess the prevalence and distribution of potato viruses in different potato growing areas in Uganda. Virus diagnostic surveys were conducted across the main potato producing regions and virus detection was done using DAS-ELISA and RT-PCR techniques. The study showed that the most widely distributed and economically important potato viruses were: PVS (31-90.9%), PLRV (2.6-81.3%), PVY (7.1-54.5%) and PVX (8.3 -53.3%); while the least detected viruses were PVM (18.2%) and PVA (9%). The viruses were prevalent either singly or in mixtures. Up to 42.8% of the samples were infected with one virus, 20.9% with two viruses and 4.2% with three viruses; while no virus was detected in 31.3% of the samples. Of the double infections, the PVY+PVS combination was the most common and widely distributed (2.1-18.2%) in 12 districts; followed by PVY+PLRV (1.8-21.3%) occurring in six districts, PVM+PVS (7.9-16.7%), PLRV+PVX (2.4-14.3%) in 5 districts and PVY+PVX (2.4-4.4%) in 3 districts. Triple infections involving PVY+PLRV+PVS were recorded at prevalence levels of 2.2-18.6% in six district. Altitude, temperature, varieties and seed sources showed relationships with the variation in the prevalence of the viruses. There were high virus prevalence and disease severity levels in low altitude areas (1088-1334 m.a.s.l) of mid-western sub-region (Mbarara and Lwengo), Central (Kibaale, Mubende) and Mid Northern (Pader) sub region compared to high altitude areas (&gt;1600 m.a.s.l). The Virus risk Area Modeling results showed the largest area (48.6%; 1,308,160 ha) at moderate risk of virus infection; while 27.3% (732,305 ha) was at high risk of virus infection. Based on the distribution level of the viruses, potato production could be intensified in areas with less virus pressure mainly, in parts of West Nile and Rwenzori regions.</p> A.A. Byarugaba, S.B. Mukasa, A. Barekye, P.R. Rubaihayo Copyright (c) Differential and comparative screening of cowpea varieties to Striga gesnerioides (Willd.) Vatke for race specific identification in Burkina Faso <p>Significant efforts have been made to develop cowpea (Vigna unguiculata (L.) Walp.) varieties resistant to Striga gesnerioides in Burkina Faso. Despite these efforts, the resistant genotypes developed still express differential responses to Striga gesnerioides in different zones of the country. This suggests existence of intraspecific variability within the parasite. The objective of this study was to assess the intraspecific variability of cowpea genotypes to Striga gesnerioides infection in Burkina Faso. Ten cowpea varieties were screened over two consecutive years, under artificial infestation with 30 ecotypes of Striga seeds at Kamboinsé research station, in a screenhouse in Burkina Faso. Cowpea varieties used included Moussa local, Komsaré and KVx404-8-1, which are susceptible to all Striga ecotypes; and varieties B301, IT93K-693-2 and IT82D-849, which are free from all Striga ecotypes infestation. Cowpea varieties Tiligré, 524B, local Gorom and Niizwè had specific reactions depending on the ecotypes. The study highlights the existence of varietal specificities according to the geographical origin of Striga gesnerioides seeds. The structuring of the intraspecific diversity showed five biotypes, of which three were clearly identified as SG1, SG5 and SG Kp races; and two biotypes could not be identified. Although this study did not allow for a clear determination of the racial affiliation of the two new biotypes, it offers the possibility of developing new strategies to control Striga by focusing on the selection of resistant varieties based on regional specificities of Striga races in each agricultural zone.</p> P. Sawadogo, T.J. Ouedraogo, Z. Dieni, T.B.J. Batieno, N. Sawadogo, S.L. Poda, H. Zongo, K. Gnankambary, J.B.S. Tignegre, M. Sawadogo Copyright (c) Inheritance of seed quality traits and concentrations of zinc and iron in maize topcross hybrids <p>Information about the mode of inheritance of maize (Zea mays L.) seed quality traits is crucial in planning for improvement programmes for such traits. The objective study was to determine mode of inheritance and interrelationships between seed quality traits, and Fe and Zn contents in maize. Twenty-six maize genotypes were considered for evaluation in this study. Additive gene action was prevalent for most seed quality traits (&gt;50%); while non-additive gene action was preponderant for Fe and Zn concentrations. Inbreds TZEEI82 and TZEEI64 were outstanding in terms of GCA male effects for conductivity (-0.13** and -0.06*), root number (0.79** and 0.30*), and root fresh weight (0.90*). Genotypes TZEEI81, DTE-STR-Y-SYN-POP-C3, 2009-TZEEI-OR1-STR and 2009-TZEE-OR1-STR-QPM were identified as excellent pollen parents for Fe concentration; and TZEEI58 and TZEEI64 for Zn concentration. In addition, only germination index had a significant additive genetic relationship with Fe content (r=0.57*); while both shoot fresh and dry weights had significant positive correlations with Zn content (r=0.45*, 0.53*). Overall, it is clear that different modes of gene action control inheritance of seed quality traits and Fe and Zn concentrations. </p> R.O. Akinwale, A.O. Fadoju, B.H. Sulola, A. Oluwaranti , F.E. Awosanmi Copyright (c) Efficacy of spraying intervals of Ridomil Plus 66 WP for control of taro leaf blight disease <p>Taro leaf blight causes up to 100% yield loss in susceptible taro (<em>Colocasia esculenta</em> L. (Schott)) cultivars. The use of fungicides in disease management is fast and effective; however efficacy of fungicides could be affected by frequency of application. The objective of this study was to evaluate the efficacy of spraying intervals and economic benefits of Ridomil Plus 66 WP (12% Metalaxyl-M and 60% Copper (1) oxide) on taro leaf blight disease. The study consisted of four fungicide spraying intervals, viz at one, two and at four weekly intervals, all at the concentration of 3.3 g l-1 and no fungicide application as the control. Results showed no significant differences (P &gt; 00.5) between one and two weekly spraying intervals in terms of taro leaf blight disease incidence and severity. These were, however, significantly different (P &lt; 0.05) from four weekly and no fungicide applications. Taro corm yield was higher in weekly spraying interval, but not significantly different (P &gt; 0.05) from biweekly application intervals. Yields in weekly intervals were 2.9, 33.0 and 44.0% higher than biweekly, four weekly and no application intervals. Applying fungicide at a biweekly interval was found to be economically efficient as it recorded higher total revenue and net present values. Applying 66 WP (12% Metalaxyl-M and 60% Copper (1) oxide) at 2 weekly interval was the optimum period and most efficient to reduce the incidence and severity of Phytophthora leaf blight disease and increase yield of taro. </p> J. Adomako, N.E. Amengor, S. Larbi-Koranteng, F. Kankam Copyright (c) Mapping of soil nutrient deficiency in oil palm plantations of Southern Benin <p>Soil degradation poses a threat to sub-Saharan sustainability of agriculture namely because of chemical and physical degradation. The objective of this study was to characterise soil properties in oil palm plantation in the districts of Ouémé and Plateau and develop spatial maps for soil nutrients useful in agricultural land use as a basis for designing soil fertility management strategies. A survey carried out in oil palm (Elaeis guineensis Jacq.) plantations in the southern Benin, revealed mineral deficiency symptoms consequent to poor mineral nutrition of the plant. A total of 428 soil composite samples were collected under farmers’ adult oil palm trees, randomly selected. These oil palm plantations were located on four soil types: Acrisol, Plintics and luvisols, Hydromorphic soil and Vertisols. In total, 370 samples were collected on plantations under Acrisols, 22 samples under Plintics and luvisols, 26 samples under Hydromorphic soil and 10 samples under Vertisols. Geostatistic methods were used to determine the spatial variability; and semi-variogram methods were established using ordinary kriging. A strong spatial dependency for nitrogen, phosphorus, potassium and magnesium was observed; while spatial dependency of calcium was moderated. The map of nutrient deficiency revealed two large areas. The first, included the districts of Bonou, Adjohoun, Sakété, Adja-Ouèrè, and Pobè, where oil palm plants showed an acute nitrogen, phosphorus and potassium deficiency; and the second area of Dangbo, Missérété, Ifangni, Avrankou, Adjarra which presented nitrogen, potassium and slight phosphorus deficiency in the oil palm plantations. Most of the soils under the oil palm plantations showed nitrogen, phosphorus and potassium deficiency.</p> N.S. Kindohoundé, L. Nodichao, N.S.H. Aholoukpè , A. Saïdou Copyright (c) Farmers’ perceptions of climate change and adaptation strategies on sorghum productivity in the Sudanian and Sahelian zones of Mali <p>In Mali, climate change is a major threat to the productivity of food security crops such as sorghum (<em>Sorghum bicolor</em> (L.) Moench, 1794). The objective of this study was to analyse farmers’ perceptions of climate change effects, on sorghum productivity and the adaptation related strategies. A total of 352 sorghum farmers in the Sudanian and Sahelian zones of Mali were interviewed, using a semi-structured questionnaire. Data collected were related mainly to the farmers’ socio-economic profiles, indicators used to characterise climate change and strategies developed to cope with it. Irregular rainfall, marked rise in temperatures and early cessation of the rainy seasons were the main manifestations of climate change effects according to the respondents. These effects reportedly resulted in a drastic drop in sorghum yields. Use of meteorological information (19.89% of the respondents), use of early and drought-resistant varieties (13.35% of the respondents), and intercropping of sorghum with other crops (25.85% of the respondents) were the strategy options adapted by farmers. The choice of an adaptation strategies was largely dependent on the number of years of experience in sorghum production, and the number of labour providers available in the household. It is imperative to assess and refine the agronomic effectiveness of these coping strategies to improve sorghum productivity in the study areas.</p> L. Traoré, O.D. Bello, A. Togola, I. Balogoun, F. Chabi, I. Yabi, E.L. Ahoton , A. Saïdou Copyright (c)