This research aimed to evaluate the effect of salt and temperature stress on water uptake and respiration of watermelon seeds during germination process and to quantify changes in the activity of the antioxidant enzymes ascorbate peroxidase (APX), catalase (CAT) and glutathione-S transferase (GST) involved in protection against reactive oxygen species. The research was performed at the Seed Analysis Laboratory (LASESA) of Embrapa Semi-Arid, Petrolina, Pernambuco State, Brazil, from september to december 2011. The experimental design was completely randomized in a factorial 2x3 (cultivars x stress conditions) for respiration evaluation, 3x4 (cultivars x electrical conductivities) for salt stress assays and 3x3 (cultivars x temperature) for temperature stress assays. The data were submitted to the mean test and evaluated using the standard errors of means. Respiration was measured by CO2 releases by watermelon seeds cv. cv. Crimson Sweet and Charleston Gray evaluated by an infrared gas analyzer, from 0-120 hours of seed imbibition in different environmental conditions (0 dSm-1/25°C, 0 dSm-1/30°C, 4 dSm-1/25°C). The antioxidant enzymes ascorbate peroxidase (APX), catalase (CAT) and glutathione-S transferase (GST) were evaluated in cvs. Crimson Sweet, Charleston Gray and Fairfax seeds and seedlings after five days imbibition in different electrical conductivities (0, 4 and 6 dSm-1) or temperatures (20, 25, 30°C). Crimson Sweet seed respiration rate was increased with increasing temperature, salinity however did not influence the respiration of seeds until the radicle protrusion. The activities of APX and CAT enzymes were antagonistically influenced stresses. The activity of GST was not altered with increased electrical conductivity, however high temperatures led to increase of its activity in watermelon seedlings. The antioxidant detoxification system was activated when imposing temperature and salt stress in all studied watermelon cultivars. Different cultivars of watermelon show different adaptation to salt and temperature stress.
Aims: In the current study we try to clarify the mechanism that might be involved in the ameliorating effects of Nano-silicon (NSi) and Silicon (Si) on faba bean (Vicia faba) plants grown under different levels of salinity stress that we found in a previous study. Study Design: Factorial completely randomized design Pot experiments were used with NSi and Si applied at 4 concentrations each (0, 1, 2 and 3 mM) and NaCl (0, 50, 100 and 200 mM) were studied. Place and Duration of Study: Experiments were carried out in the greenhouse of the Experimental Station, Faculty of Science, Princess Nora Bint Abdulrahman University, Kingdom of Saudi Arabia during winter season of 2012/2013. Methodology: Effects of NSi and Si on membrane characteristics, photosynthetic pigments, sugar content, free proline, antioxidant enzymes and mineral elements were investigated in NaCl stressed and non-stressed faba bean plants. The experiment was arranged in a factorial design with 4 replications at NaCl levels of 0, 50, 100 and 200 mM. The tested NSi and Si concentrations were 0, 1, 2 and 3 mM for each. Results: NaCl treatments caused an increase in proline content and in some enzyme activities, Chl a, b and carotenoids were decreased. Application of NSi caused a significantly increase in the activity of ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POD) in plant leaves, but caused a decrease in the activity of superoxide dismutase (SOD) as compared to unstressed plants. Oxidative damage, produced by salinity stress, seemed to decrease in accordance with the increase in antioxidant enzymes activity under NSi and Si treatments, thus tolerance against salt stress was observed. The improvement of salt tolerance resulted from NSi and Si treatments was accompanied with improved membrane stability, chloroplast formation and sugar accumulation. Conclusion: Nano-silicon treatments can reduce the adverse effects of salinity on V. faba plants by enhancing the activity of antioxidant enzymes.
Study to evaluate the insecticidal efficacy of pyrethrum, Chrysanthemum cinerariifolium, relative to a synthetic insecticide (Cypermethrin 10 E. C) in the control of some field pests of groundnut was carried out at the Teaching and Research Farm, School of Agriculture and Agricultural Technology, Federal University of Technology, Owerri, southeastern Nigeria, from March to November, 2012. The experiment was laid out in a 2 x 4 factorial arrangement fitted into a Randomized Complete Block Design replicated three times. Groundnut seed variety, ICGV-IS 96894 (ICRISAT) was subjected to germination test to ensure viability. Seeds were planted at a spacing of 30 cm x 15 cm (220,000 plants/ha) on 24 (1 m2) beds with 1 m between furrows. Pyrethrum was extracted through a simple replicable procedure and tested at four rates (0.00, 0.25, 0.50, 0.75 g/100 ml of water). Cypermethrin 10 EC was tested at 0.00, 0.50, 1.00 and1.50 ml/100 ml of water. Insecticides application, pest sampling and leaf damage assessments were carried out at 4, 6 and 8 weeks after planting (WAP). Yield measurement parameters (seed weight, shell weights and pod density) were assessed. Major arthropod pests identified were; Macrotermes bellicosus Smeathman, Peridontopygespp., Helotrichia serrata Fabricius, and Oedaleus nigeriensis Uvarov. Cypermethrin and pyrethrum applications reduced pest incidence (3.25, 2.50, 2.10 insects) and (4.09, 3.62, 3.42 insects), respectively, when compared with unsprayed plots (6.35, 6.16, 6.20 insects) at 4, 6 and 8 WAP. Insecticide type had no significant effect on the population of majority of sampled pests. Sprayed plots had less damaged leaves - 2.80 (cypermethrin) and 2.83 (pyrethrum) as against 4.52 leaves in unsprayed plots at 8 WAP. Sprayed plots also had increased fresh pod weight (0.61, 0.52 kg in cypermethrin and pyrethrum sprayed plots, respectively) as against 0.14 kg in unsprayed plots. Seed weights (0.26, 0.22 kg in cypermethrin and pymethrum sprayed plots, respectively) were significantly distinct from the control (0.06 kg).There were no significant differences (P = .05) in the dry pod or shell weights based on insecticide types. The efficacy of the insecticides was dose related as higher rates gave better performances. Pyrethrum compared favourably with cypermethrin in controlling the field insect pests of groundnut and could serve as alternative to synthetic pesticides in the management of these pests in southeastern Nigeria.
Steeping of dormant jute mallow (Corchorus olitorius L.) seed in hot water at high temperature for enhanced germination, seems to be the most favoured of all other methods. Literature however, appears to be silent on the cooling protocol to adopt to ensure high quality after a seed lot may have been steeped in hot water. Seeds of two cultivars of this crop were subjected to nine hot water/cooling treatments and then dried back. They were then thinly spread and stored in open glass dishes at 83% relative humidity and 33°C. The moisture content of seeds steeped in water at 80 and 97°C increased from about 5-6% prior to storage to about 10-11% after 6-18 weeks after storage (WAS). Steeping of seeds at 80 and 97°C for 5 seconds significantly enhanced germination to about 88% and 77% in ‘Amugbadu’ and ‘Oniyaya’ respectively compared to about 8% in the control (unsteeped) seed. Cultivar ‘Amugbadu’ seeds steeped in cold water (ca 27°C) immediately after steeping in water at 97°C recorded higher germination percentage of 90% - 46% within 0-12 weeks of storage compared to the range of 88 to 29% recorded within the same period in seeds that were simply left to gradual cooling in ambient condition. ‘Oniyaya’ seeds exhibited no differential response to cooling protocol. Unsteeped (control) seed of both cultivars recorded higher germination of 82/85% at 20 WAS than seeds steeped at 97°C (irrespective of cooling protocol) and 80°C prior to storage. Furthermore, whereas seeds of the latter group germinated slower and less uniformly as storage progressed, a gradual increase in the values of these vigour indices were recorded in the former group of seeds. Across steeping treatments the germination percentage of ‘Oniyaya’ seed declined less rapidly than that of ‘Amugbadu’ seeds during storage from ca 61% to 32% in the former compared with about 62% to 3% in the latter.
A multivariate analysis was performed on some soil nutrient and Cone Index (CI) data from the research and demonstration farm of the Dept. of Agricultural Sciences, University of Juba in South Sudan. The main objective of the study was to characterize the spatial distribution of the soil nutrients: N, P, K, Fe and Mn as well as soil penetration resistance CI. A Principal Component Analysis (PCA), Gaussian Mixture Model (GMM) and Hierarchical Cluster Analysis (HCA) were performed on the analyzed samples. The Bayesian Information Criterion (BIC) was used for model selection between the Equal size, Equal shape and Equal orientation (EEE) and Equal size, Equal shape and Variable orientation (EEV) models which defined the size, shape and orientation of the ellipsoid with full covariance matrices. Eigenvalues of the three major principal components F1, F2 and F3 accounted for 75.67% of the total variance of the data. From hierarchical clustering, P was observed to cluster with Fe, Mn with N which at second level clustered with K then with CI. The results of the PCA showed that Nitrate-N, Mn and Kwere strongly influenced by CI and so determining their spatial distribution. This could be associated mainly to earlier anthropogenic activities on the soil. The results of this study also showed spatial relationships between individual soil nutrients with both K and P mutually antagonistic with Nitrate-N, whereas between K and P where mutually synergistic. While P was strongly adsorbed to Fe, this was associated to lithogenic soil materials and therefore interpreted as derived from natural sources of the Eutric Leptosol. The goodness-of-fit test using the Kolmogorov-Smirnov (KS) showed that the values of the variables: CI, K, P and Fe were significant at p ≤0.05 and that the data followed normal distribution, whereas Mn and Nitrate-N were not. The KS test also corroborated the results of strong spatial dependency of each variable at less than 25%. The multivariate GMM adequately described the spatial distribution of all measured variables than the unimodal Gaussian.
This study was conducted using 96 day old broiler chicks, to assess the most appropriate level of inclusion of whole millet meal as a substitute for maize. The inclusion levels of the whole millet were 0, 20, 40 and 60% of the maize content of the control diet. The birds were randomly assigned to four dietary treatments which were replicated four times using Completely Randomized Design (CRD). The study lasted for 56 days. Feed and water were provided ad libitum during the study. The weight of the birds, daily feed intake, feed cost per treatment and mortality records were kept. At the end of the experiment, one bird per replicate was randomly selected for carcass and organ evaluation. These were expressed as percentages of the body weight. Data collected were subjected to Statistical Analysis System (SAS) and errors were presented as standard errors of means (SEM). The inclusion of whole millet significantly influenced feed intake and feed conversion ratio. Significant differences were not observed in carcass, organ and other parameters measured. It was observed from this study that the performance, carcass and organ yield of broiler fed up to 60% whole millet in the diets as substitute for maize were equivalent to those fed the control diet. However, the 20% whole millet inclusion which gave the best feed conversion ratio and had similar final weight compared with the others was recommended for best broiler performance in a humid tropical environment.
Aim: This study was conducted to assess the influence of different water and rice straw management practices and rice genotypes on growth and yield of rice in Uganda. Study Design: Field experimental design was a Randomized Complete Block Design while the screen house study design was a Completely Randomized Design. Place and Duration of Study: The study was conducted in the field at National Crops Resources Research Institute (NaCRRI) Namulonge and in the screen house at Kyambogo University during the period of February-July 2013. Materials and Methods: Ten rice genotypes obtained from the cereals program at NaCRRI Namulonge were grown under different water management regimes, with and without rice straw incorporation both in the field and screen house. Water management regimes used were alternate wetting and drying (AWD), continuous flooding (CF) and continuous drying (CD). Results: A significant variation in grain yield was observed among rice genotypes and under different water management regimes (P<0.001). Use of rice straw influenced rice yield in the screen house (P<0.001) but not in the field (P=0.23); interactions of water management x genotype and water management x rice straw x genotype influenced rice yield in the field (P=0.003) but not in the screen house (P=0.5). Higher yield gain was observed under the water-saving technology alternate wetting and drying compared to continuous flooding or drying. Conclusion: This study has indicated significant variations in field performance of rice under different water management regimes and rice straw usage. These findings are therefore important because they suggest that efficient management of water resources and rice residues from rice fields coupled with the use of drought tolerant rice varieties could be an effective integrated approach to improve rice yield and an adaptation strategy to the observed climate variability.