Characterisation and control of Curvularia lunata infecting farmer-saved rice seeds in Ghana

Curvularia species are increasingly important seed-borne fungi, whose identification has been done based solely on cultural and morphological features in Ghana. To confirm the identity of the fungus in Ghana, isolates of the fungus obtained from farmer-saved rice seeds were identified using cultural and morphological features, complemented with phylogenetic analysis of the internal transcribed spacer regions of isolates. The susceptibility of isolates to three plant based fungicides, Levo, Kobe and Ex-icute was determined with in-vitro and in-vivo. All isolates produced curved shaped spores with several septations. In the phylogram, they all clustered in the C. lunata clade, confirming their C. lunata species status. All isolates were susceptible to the three organic fungicides and seeds treated with the three fungicides reduced fungal infection percentage. For safer environmental practices, these plant based fungicides are recommended for rice seed treatment

Mycofloral Diversity and Molecular Characterization of Species Isolated from Farmer-Saved Rice Seeds in the Irrigated Rice Production Districts of the Coastal Savannah Zones of Ghana

Irrigated rice production is the major type of rice production in the Coastal Savannah Zone of Ghana, where farmers rely on their saved seeds for production. A study was carried out to determine the types of storage fungi resident on farmer saved seeds and their distribution in five major rice production areas of the Coastal Savannah Zone. The blotter method was used to isolate fungal species after which they were identified using cultural and morphological features complemented by sequence analysis of the entire Internal Transcribed Spacer (18S-ITS1-5.8S-ITS2) region of isolates. Eleven fungal species namely, Alternaria alternata, Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Colletotrichum gloeosporioides, Curvularia lunata, Curvularia geniculata, Fusarium equiseti, Lasiodiplodia theobromae, Rhizopus oryzae and Trichoderma sp. belonging to 8 different genera were isolated and identified on the rice seeds. Curvularia lunata, with a percentage occurrence of 63.9% was the most prevalent fungal species, while Trichoderma sp. (1.3%) was the least prevalent fungal species from the study area. The high infection rate of seeds by Curvularia species may lead to high incidence and severity of Curvularia leaf spot disease in the study area. &nbsp

Performance of rice under different water regimes and plant nutrient sources

Field experiment was carried out at the Soil and Irrigation Research Centre, University of Ghana, Kpong in 2015 and 2016 cropping seasons to evaluate the effect of different soil water condition and plant nutrient sources on the growth and yield of rice. The experiment was laid out in a split plot design with three replications. Water regime and nutrient source were the main and sub-plot factors, respectively. Water regimes included; continuous flooding (CS), alternate wetting and drying (AWD) and moist soil condition between field capacity and permanent wilting point (MC) while the nutrient fertilizer treatments included no fertilizer (N0), 90 kg N/ha mainly from urea fertilizer (N1), 90 kg N/ha from 12.8 tons of compost (N2) and 45 kg N/ha from urea fertilizer + 45 kg N/ha from 6.4 tons of compost (N3). Results from the study revealed that keeping the soil periodically in aerobic and anaerobic condition through AWD method of water management recorded similar growth and grain yield of rice as with complete submergence of paddy field. Combination of inorganic fertilizer and compost for each to supply 45 kg N/ha under AWD produced the highest rice growth and grain yield. There was a positive and significant correlation between grain yield and growth parameters (plant height, chlorophyll content and above ground biomass accumulation).

Evaluation of the nutritional composition ofthe seeds of some selected African yam bean (Sphenostylis stenocarpa Hochst Ex. A. Rich (Harms)) accessions

African yam bean (AYB) is an important but neglected and underutilized crop producing edible seeds and tubers. The poor awareness of the nutritional values of AYB constitutes one of the major problems limiting its utilization. This study was, therefore, carried out to determine the nutritional potentials of five accessions of African yam bean (TSs 125, TSs 116, TSs 86, TSs 69 and TSs 60) by analyzing their proximate composition and micronutrients (Iron (Fe), Zinc (Zn) and Selenium (Se)). The experiment was laid out in completely randomized design (CRD) with three replications. The results obtained showed significant (p < 0.05) variations in the proximate composition of the AYB accession. The crude protein was in the range of 21.84-23.41 %, crude fat 3.40-3.86 %, fibre 6.17- 6.76 %, carbohydrate 52.8-54.48 %, dry matter 90.42 - 90.6 %, ash 4.22 - 4.35 %, and moisture 9.4 - 9.58 %.The Se concentration varied from 312 mg/100 g in TSs 116 to 58 mg/100 g in TSs 60 while Fe ranged between 10.40 mg/100g in TSs 60 and 6.07mg/100gin TSs 86. Zinc varied between 8.83 mg/100g in TSs116 and 6.37 mg/100 g in TSs 69.TSs 116 was best accession in terms of crude protein, dry matter, ash, selenium and zinc, while TSs 60 was best in terms of iron. The study revealed AYB seeds as a food crop rich in protein, carbohydrate, fibre, selenium, iron and zinc. The genotypic variability can be exploited in developing African yam bean varieties with better qualities in terms of nutrient density.Keywords: Neglected, underutilized, nutrient-dense, micronutrient and protei

Use of Corn Cob and Rice Husk Biochar as Liming Materials in Acid Soils

Most soils in Ghana are acid with those of the Evergreen Rain Forest belt having Al toxicities. Unavailability, high cost and poor grade of conventional liming materials have led to poor yields of food crops grown on these acid soils. Preliminary works on biochar produced from agricultural waste in Ghana have shown that some types have high concentration of basic cations and contain CaCO3, an active ingredient in conventional lime. Biochar could, therefore, be exploited for use as liming material.  However, the biochar type that would be ideal for use as liming material in acid soils of Ghana has received little attention. Two typical acid soils viz., Typic Hapludox and Typic Hapludult were thus amended with corn cob and rice husk charred at 500 and 700 oC at a rate of 80 Mg/ha in a screen house experiment to evaluate their respective efficacies as substitutes for conventional agricultural lime. The Ca equivalent of the biochar types from CaCO3, the conventional lime, was amended to the soils to serve as realistic controls. The amended soils, in addition to their un-amended counterparts, were all kept at 80% field capacity in a completely randomized design in the screen house to allow for pH equilibration amidst weekly pH and bi-weekly exchangeable Al, Ca and Mg monitoring. Results showed that corn cob charred at 500 oC was able to raise pH from 4.2 to 5.2 in Hapludox and from 4.9 to 6.2 (an optimum pH for most food crops) in Hapludult within a six-week incubation period. All the biochar types reduced Al concentration from 0.4 cmolc /kg to undetectable levels in the Hapludult. The element was reduced from 1.3 cmolc /kg to 0.45 cmolc /kg in the rice husk and corn cob charred at 700 oC amended Hapludox

Nutritional and antioxidant composition of eggplant accessions in Ghana

Eggplants ( Solanum spp.) are important vegetable crops, well known for nutritional and medicinal values of their fruits and leaves. In order to select more nutritious varieties in Ghana, 33 eggplant accessions were investigated for nutritional, mineral and antioxidant content of their fruits. Proximate and antioxidant analysis were determined by AOAC and DPPH methods. The results showed significant differences (P<0.05) among nutritional, mineral and antioxidant traits. Most accessions contained high moisture content (above 70%). Nutrient concentrations ranged from 0.10 fat to 6.10 g 100 g-1 carbohydrate; and 0.107 magnesium to 11.271 mg 100 g-1 iron. Total phenolic content was highest in accession ST004-03 (210 mg GAE g-1 (gallic acid equivalent), and lowest in SA002-02 (171.10 mg GAE g-1). Accessions ST004-02 and ST004-03 displayed the highest DPPH (2, 2-diphenyl-1-picrylhydrazyl) radical scavenging activity (0.017 mg ml-1); while San 005-01 (1474 mg ml-1) showed the highest antioxidant content. Principal component analysis indicated that the first 3 components with Eigen value >1.5 contributed 68.68% of total variability. Dry matter, protein, moisture and carbohydrate contents showed maximum contributions to the total variability. Biplot analysis displayed strong and positive associations among ash, protein and moisture with dry matter; moisture and carbohydrate and; protein and ash. Accessions San 005-01, San 005-02, SA 002-07, SA 002-08 and ST004-03 were identified as good sources of nutrients, minerals and antioxidant properties among the others; and could be used as potential donors for hybridisation programme to develop varieties with higher concentration of these traits.Les aubergines ( Solanum spp.) Sont des cultures l\ue9gumi\ue8res importantes, bien connues pour les valeurs nutritionnelles et m\ue9dicinales de leurs fruits et de leurs feuilles. Pour s\ue9lectionner des vari\ue9t\ue9s plus nutritives au Ghana, 33 accessions d\u2019aubergines ont \ue9t\ue9 \ue9tudi\ue9es pour d\ue9terminer la teneur nutritionnelle, min\ue9rale et antioxydante de leurs fruits. Les analyses proximale et antioxydante ont \ue9t\ue9 d\ue9termin\ue9es par les m\ue9thodes AOAC et DPPH. Les r\ue9sultats ont montr\ue9 des diff\ue9rences significatives (P <0,05) entre les caract\ue9ristiques nutritionnelles, min\ue9rales et antioxydantes. La plupart des accessions avaient une teneur en eau \ue9lev\ue9e (sup\ue9rieure \ue0 70%). Les concentrations de nutriments allaient de 0,10 \ue0 6,10 g de glucides \ue0 100 g-1; et 0,107 magn\ue9sium \ue0 11,271 mg 100 g-1 de fer. La teneur totale en compos\ue9s ph\ue9noliques \ue9tait la plus \ue9lev\ue9e lors de l\u2019accession ST004-03 (210 mg GAE g-1 (\ue9quivalent d\u2019acide gallique) et la plus faible dans le SA002-02 (171,10 mg GAE g-1). Les accessions ST004-02 et ST004-03 ont pr\ue9sent\ue9 l\u2019activit\ue9 de pi\ue9geage de radicaux DPPH (2,2-diph\ue9nyl-1-picrylhydrazyle) la plus \ue9lev\ue9e (0,017 mg ml-1); tandis que San 005-01 (1474 mg ml-1) pr\ue9sentait la plus forte teneur en antioxydants. L\u2019analyse des composantes principales a montr\ue9 que les 3 premi\ue8res composantes avec une valeur propre sup\ue9rieure \ue0 1,5 ont contribu\ue9 \ue0 68,68% de la variabilit\ue9 totale. Les teneurs en mati\ue8re s\ue8che, en prot\ue9ines, en humidit\ue9 et en glucides ont contribu\ue9 au maximum \ue0 la variabilit\ue9 totale. L\u2019analyse bi-parcelle a montr\ue9 des associations fortes et positives entre les cendres, les prot\ue9ines et l\u2019humidit\ue9 avec la mati\ue8re s\ue8che, l\u2019humidit\ue9 et les glucides; prot\ue9ines et cendres. Les accessions San 005-01, San 005-02, SA 002-07, SA 002-08 et ST004-03 ont \ue9t\ue9 identifi\ue9es comme \ue9tant de bonnes sources d\u2019\ue9l\ue9ments nutritifs, de min\ue9raux et de propri\ue9t\ue9s antioxydantes; et pourrait \ueatre utilis\ue9 comme donneur potentiel pour le programme d\u2019hybridation visant \ue0 d\ue9velopper d\ue9velopper des vari\ue9t\ue9s avec une concentration plus \ue9lev\ue9e de ces caract\ue8res

Gene effect and heritability of yield and its components in eggplant

Eggplant ( Solanum melongena L.) is one of the most important fruit vegetables in the world, with several nutritional and medicinal benefits. However, little is known about the genetic divergence of yield and its related traits. The objective of this study was to explore gene action and heritability of traits to help direct and strengthen breeding programmes, geared towards improving yield of the crop. Six generations (P1, P2, F1, F2, BC1 and BC2) derived from two crosses (SM001-07 x ST004-03 and SM001 x San005-01) of eggplant accessions, were grown in pots in an open field, using Randomised Complete block Design (RCBD). Estimated data indicated that, the additive-dominance model was adequate to demonstrate the genetic variation and its significance in the inheritance of fruit weight, days to flowering and fruit yield traits. Although non-allelic interactions were found in plant height and number of seeds, additive effect was more pronounced in the genetic control of days to flowering and fruit weight; while dominance effect was more important in the control of plant branching and fruit length. Plant height and fruit yield were influenced by complementary gene action. Furthermore, the study revealed low magnitudes of dominance and environmental variances for most traits showing higher heritability values. In view of the diverse gene actions, with additive, dominant and epistasis, playing significant roles in the control of different traits, backcross, recurrent selection or bi parental could be appropriate for advancing the segregating populations to meet the need of yield improvement in both crosses.L\u2019aubergine ( Solanum melongena L.) est l\u2019un des legumes fruits les plus importants au monde, avec les plusieurs bienfaits nutritionnels et m\ue9dicinaux. Cependant, on sait peu de choses sur la divergence g\ue9n\ue9tique du rendement et ses traits li\ue9s. L\u2019objectif de cette \ue9tude \ue9tait d\u2019explorer l\u2019action des g\ue8nes et l\u2019h\ue9ritabilit\ue9 des traits pour aider \ue0 diriger et \ue0 renforcer les programmes de s\ue9lection visant \ue0 am\ue9liorer le rendement de la culture. Six g\ue9n\ue9rations (P1, P2, F1, F2, BC1 et BC2) d\ue9riv\ue9es de deux croisements (SM001-07 x ST004-03 et SM001 x San005-01) d\u2019accessions d\u2019aubergines ont \ue9t\ue9 cultiv\ue9es en pots dans un champ. Les donn\ue9es estim\ue9es indiquent que le mod\ue8le de dominance additive \ue9tait ad\ue9quat pour d\ue9montrer la variation g\ue9n\ue9tique et son importance dans l\u2019h\ue9r\ue9dit\ue9 du poids du fruit, des jours de floraison et des traits de rendement des fruits. Bien que des interactions non all\ue9liques aient \ue9t\ue9 trouv\ue9es dans la hauteur des plantes et le nombre de graines, l\u2019effet additif \ue9tait plus prononc\ue9 dans le contr\uf4le g\ue9n\ue9tique des jours de floraison et du poids des fruits; tandis que l\u2019effet de dominance \ue9tait plus important dans le contr\uf4le de la ramification des plantes et de la longueur des fruits. La hauteur des plantes et le rendement des fruits ont \ue9t\ue9 influenc\ue9s par l\u2019action compl\ue9mentaire des g\ue8nes. De plus, l\u2019\ue9tude a r\ue9v\ue9l\ue9 de faibles variation de dominance et des variances environnementales pour la plupart des traits pr\ue9sentant des valeurs d\u2019h\ue9ritabilit\ue9 plus \ue9lev\ue9es. Compte tenu des diverses actions des g\ue8nes, avec additif, dominant et \ue9pistase, jouant un r\uf4le important dans le contr\uf4le des diff\ue9rents traits, le r\ue9trocroisement, la s\ue9lection r\ue9currente ou biparentale pourrait \ueatre appropri\ue9 pour faire progresser les populations en s\ue9gr\ue9gation afin de r\ue9pondre au besoin d\u2019am\ue9liorer le rendement dans les deux croisements

Limited effects of shade on physiological performances of cocoa (Theobroma cacao L.) under elevated temperature

Open Access Article; Published online: 08 Jul 2022Shade is one of the recommended management solutions to mitigate the effects of heat stress, which is a major challenge for cocoa production globally. Nevertheless, there are limited studies to verify this hypothesis. Here, we evaluate the effects of heat and shade on cocoa physiology using experimental plots with six-month old potted seedlings in a randomized complete block design. Infrared heaters were applied for one month to increase leaf temperatures by an average of 5–7 ºC (heat treatment) compared with no heat (unheated treatments), and shaded plants were placed under a shade net removing 60% of the light compared with no shade (sun treatments). Plants under heat treatments in sun and in shade showed severe reduction in photosynthesis. Measurements of chlorophyll fluorescence and photosynthetic light response curves indicated that heat caused damages at photosystem II and additionally resulted in lower rates of maximal photosynthesis. Temperature optima for photosynthesis were at 31–33 ºC with only small differences between treatments, and as light saturation was reached at low PAR levels of 325 – 380 µmol m−2 s−1 in shade and 427 – 521 µmol m−2 s−1 in sun, ambient rates of photosynthesis were comparable between sun and shade treatments. Heat treatments resulted in decreased concentrations of chlorophyll and changed pigment composition, reduced specific leaf areas, and plant biomass. While shade may benefit cocoa seedlings, our results indicate that the positive effects may not be sufficient to counteract the negative effects of increased temperatures on cocoa physiology

Combined effects of shade and drought on physiology, growth, and yield of mature cocoa trees

Open Access ArticleClimate models predict decreasing precipitation and increasing air temperature, causing concern for the future of cocoa in the major producing regions worldwide. It has been suggested that shade could alleviate stress by reducing radiation intensity and conserving soil moisture, but few on-farm cocoa studies are testing this hypothesis. Here, for 33 months, we subjected twelve-year cocoa plants in Ghana to three levels of rainwater suppression (full rainwater, 1/3 rainwater suppression and 2/3 rainwater suppression) under full sun or 40 % uniform shade in a split plot design, monitoring soil moisture, physiological parameters, growth, and yield. Volumetric soil moisture (ϴw) contents in the treatments ranged between 0.20 and 0.45 m3m−3 and increased under shade. Rainwater suppression decreased leaf water potentials (ѱw), reaching −1.5 MPa in full sun conditions indicating severe drought. Stomatal conductance (gs) was decreased under the full sun but was not affected by rainwater suppression, illustrating the limited control of water loss in cocoa plants. Although pre-dawn chlorophyll fluorescence (Fv/Fm) indicated photoinhibition, rates of photosynthesis (Pn) were highest in full sun. On the other hand, litter fall was highest in the full sun and under water stress, while diameter growth and carbon accumulation increased in the shade but was negatively affected by rainwater suppression. Abortion of fruits and damage to pods were high under shade, but dry bean yield was higher compared to under the full sun. The absence of interactions between shade treatments and rainwater suppression suggests that shade may improve the performance of cocoa, but not sufficiently to counteract the negative effects of water stress under field conditions

Effect of shade and level of fertilizer application on nutrient uptake and dry matter partitioning in cocoyam (Xanthosoma sagittifolium L.)

Published online: 04 Oct 2017The effect of shade and fertilizer application on nutrient uptake and dry matter (DM) partitioning in cocoyam was evaluated by growing the plant under different levels of shade and fertilizer application at Forest and Horticultural Crops Research Centre, Kade, within a period of 9 months. The shade levels used were 80%, 70%, and 50% shade, and full sunlight exposure. The fertilizer rates used were 112 kg/ha nitrogen, phosphorus and potassium (NPK) (15-15-15 120 kg/ha NPK (15-15-15) in a form) of mineral fertilizer, 112 kg/ha NPK organic fertilizer and no fertilizer (control). The split-plot design was used with shade levels as the main plot factor and fertilizer levels as the sub plot factor. The interaction effect of shade and fertilizer had a significant effect (p ≤ 0.05) on DM of cocoyam leaves, petioles, corm, and cormels as well as nutrient accumulation in plant parts. Cocoyam leaves of plants grown under 50–70% shade stored significantly higher (p ≤ 0.05) quantities of nutrients (1.51 ppm of N, 6.61 ppm of P, and 53.10 ppm of K) and accumulated more DM (71.30 g) than leaves of plants grown under full sunlight exposure which accumulated 1.37 ppm of N, 4.31 ppm of P, 26.06 ppm of K, and 30.7 g DM, at the two rates of the chemical fertilizer application. Under full sunlight exposure, significantly higher amounts of DM were accumulated in the corms and cormels at mineral fertilizer level of 112 kg/ha. At mineral fertilizer rate of 120 kg/ha, nutrient accumulation was significantly higher (p ≤ 0.05) in the corm and cormels (1.72 ppm of N and 7.72 ppm of P) of plants grown under full sunlight exposure than those grown under 70% shade level (0.6 ppm of N and 2.94 ppm of P). Nitrogen and phosphorus accumulation was significant in the petioles of plants grown under the 70% shade level at fertilizer rate of 120 kg/ha. It is recommended that cocoyam be grown under 50–70% shade at a fertilizer rate of 112–120 kg/ha for leaf production and under full sunlight exposure at 112 kg/ha (NPK) for cormel production