Showing papers in "African Journal of Plant Science in 2011"

Heritability and correlation coefficient analysis for yield and its components in rice (Oryza sativa L.)

Abstract: The objectives of this study were to estimate the phenotypic and genotypic coefficients of variation, broad sense heritability, genetic gain and correlations in rice (Oryza sativa L.). The experiment was laid out in a randomized complete block design (RCBD) with three replications in the International Institute of Tropical Agriculture, Ibadan, Nigeria during 2008/2009 cropping season. Genotypes differed significantly at (p>0.001) for all the traits studied, which implies that the genotypes constitute a pool of germplasm with adequate genetic variability. Genotypic coefficients of variation were lower than the corresponding phenotypic coefficients in all the traits studied, indicating considerable influence of the environment on the expression of the traits. High to medium broad sense heritability estimates observed on days to heading, days to maturity, plant height, grain yield and number of grains per panicle, panicle weight, number of panicles per m2 and panicle length suggests high component of heritable portion of variation, which is the portion exploited by breeder and that selection for these traits can be achieved directly based on their phenotypic performance. The low broad sense heritability observed for the number of tillers per plant and 1000 grain weight is indicative of the influence of the environment on these traits. Low heritability of these traits indicates the ineffectiveness of direct selection for these traits. High to medium heritability and genetic advance were recorded for the number of grains per panicle, grain yield, panicle weight and the number of panicles per plant. This suggests that these traits are primarily under genetic control and selection for them can be achieved through their phenotypic performance. Grain yield exhibited significantly positive correlation with the number of tillers per plant (r = 0.58**), panicle weight (r =0.60*) and number of grains per panicle (r= 0.52*). Therefore, the results suggest that these traits can be used for grain yield selection. Key words: Broad sense heritability, rice, genotypic coefficient of variation, phenotypic coefficient of variation, genetic gain, rice yield, yield components.

An overview of Citrus aurantium used in treatment of various diseases

Abstract: Citrus aurantium (bitter orange) is a plant belonging to the family Rutaceae, The most important biologically active constituents of the C. aurantium fruits are phenethylamine alkaloids octopamine, synephrine, tyramine, N-methyltyramine and hordenine. It is rich in vitamin C, flavonoids and volatile oil. Synephrine is a primary synthesis compound with pharmacological activities such as vasoconstriction, elevation of blood pressure and relaxation of bronchial muscle. whose fruit extracts have been used for the treatment of various diseases such as gastrointestinal disorders, insomnia, head aches, cardiovascular diseases, cancer, antiseptic, anti-oxidant, antispasmodic, aromatic, astringent, carminative, digestive, sedative, stimulant, stomachic and tonic and by research novel use is found in obesity and related risks even life threatening are continuously increasing through out world in all age groups. Many marketed formulations claim to possess antiobesity actions, but still many herbs which have claims to this need to be investigated and their claims to be authenticated. In recent era there is a great thrust on screening of herbal extracts and formulations for antiobesity action. In this article efforts have been taken to discuss the photochemistry, constituents, ethnobotany, pharmacology safety and toxicity of citrus plant. The motto is to discuss C. aurantium here more research attention should be given on this that would increase its use in various chronic and acute diseases Key words: Bitter orange, synephrine, obesity, thermogenesis, ethnobotany.

Multivariate assessment of the agromorphological variability and yield components among sweet potato (Ipomoea batatas (L.) Lam) landraces

Abstract: Understanding the nature and magnitude of variability existing among sweetpotato genetic materials for important traits is vital for the effective utilization of such materials for breeding purposes. Eighteen landraces from diverse origins, plus three released cultivars as checks, were evaluated in two contrasting locations, using nine agronomic and eight morphological traits of the crop, to estimate the nature and magnitude of the variability among the genetic materials, to determine the relationships among the traits, and to identify the important yield-related traits among the collections using multivariate tools. The principal component analysis identified number of marketable and unmarketable roots, total number of roots, weight of marketable and unmarketable roots, total root weights, incidence and severity of rootCylas spp., length of biggest, medium and smallest marketable roots, number of branches, as well as stand count at harvest as important traits that could be used to differentiate the landraces. The canonical variate analysis showed that the observed variation among the traits occurred mostly between-groups than within-groups, and that it was largely influenced by total root weight, weight of marketable roots, number of marketable roots, and total number of roots. Generally, all the traits, except stand count at harvest, exhibited positive and significant (P<0.01 and P<0.001) correlation with total root weight (yield). Most of the traits also exhibited significant relationships among them. However, the use of forward selection multiple regression analysis revealed weight of marketable and unmarketable roots, as well as total number of roots as the most important yield component traits that could be used to improve sweetpotato. Thus, our work identified the existence of inherent variability in the local germplasm collections, and the traits that could be used to exploit the observed variability, eliciting important relationships among the traits in the process. Key words: Sweetpotato, genetic variability, multivariate analyses, yield components.

Micronutrients (Fe, Mn, Zn) foliar spray for increasing salinity tolerance in wheat Triticum aestivum L.

Abstract: A pot experiment was carried out to investigate the effect of foliar application of micronutrient compound on improving wheat (var. Gemiza 3) for salt tolerance. Two concentrations (0.10 and 0.15%) of suspension micronutrient compound containing Fe, Mn, Zn in ratios 1:1:1 in concentration 2.8:2.8:2.8% were sprayed. Levels of NaCl (0-1000-2000-5000 ppm) were applied to irrigation water. Results revealed that growth and nutrients uptake were reduced with increasing NaCl concentration ,Na was increased, while K, Ca, P, N as well as K/Na, Mg/Na ratios, Fe, Mn, Zn and Cu also were decreased as salinity levels increased. Foliar spraying with suspension micronutrient induced stimulatory effects on growth parameters and nutrients uptake either before or after the salinization treatments.The results of this study suggest that foliar spray with micronutrient may have a potential role for increasing wheat tolerance to salinity stress. Key words: salinity stress, foliar spray, Fe, Mn, Zn, salinity tolerance, wheat.

Grain legume impacts on soil biological processes in sub-Saharan Africa

Abstract: Grain legumes occupy about 20 million hectares in Africa. The major crops are cowpea (Vigna unguiculata L.), which is grown on about 11 million hectares mostly in West Africa, and common bean (Phaseolus vulgaris L.), grown on about 5 million hectares mostly in eastern and southern Africa. These grain legumes have impacted soil organisms, including nitrogen fixers, mycorrhizae, fauna, and the processes that they perform. The legume-Rhizobium symbiosis results in dinitrogen (N2) fixation that adds plant-available nitrogen to the soil system. Some of the fixed N2 is recycled when legume crop residues decompose for the benefit of non-legume crops grown with or after grain legumes. This N recycled by grain legumes is minimal because most of the N in these legumes is in the grain that is removed from the farm at harvest. Non-legume crops grown in rotation with legumes may also benefit from endophytic rhizobia. Mycorrhizal associations that improve plant nutrient and water uptake also benefit from the legume in a cropping system. Besides breaking pest cycles, grain legume crops also reduce disease infestation of non-legume crops by enhancing biological pest control through increased microbial diversity and activity. Legumes may contribute to greenhouse gas (nitrous oxide and carbon dioxide) emissions during nitrification and denitrification of fixed N2. However, because less fertilizer N is used in legume-based cropping systems, overall greenhouse gas emissions are usually less than those in fertilized monoculture cereals. Through their effects on soil biology, legume crops also improve soil structure by enhancing the formation and maintenance of soil aggregates. Therefore, grain legumes in Sub-Saharan Africa have positive effects on agriculture by adding and recycling biologically fixed N2, enhancing nutrient uptake, reducing greenhouse gas emissions, and improving soil structure and breaking non-legume crop pest cycles.

Salt effects on seed germination and seedling emergence of two Acacia species

Abstract: Germination is the first stage in plant life cycle confronted with soil salinity and because of expanded saline areas around the world it is important to determine salt effects on this stage. In this study, we report an in vitro procedure for studying germination of Acacia spp. under salt stress with different NaCl and KCl concentrations. Seeds of Acacia tortilis (Forssk.) Hayne and Acacia oerfota(Forssk) Schweinf after subjected to sulphuric acid and boiling water, were grown inL2 medium under eight salinity levels (0, 50, 100, 150, 200, 250 and 300 mM) in a complete randomized design under laboratory conditions. Germination of both species decreased by increasing salinity. Both Acacia species showed higher tolerance to increased level of NaCl than to KCl. Key words: In vitro culture, Acacia spp., NaCl, KCl, germination percentage, germination speed.

Comprehensive investigation into the nutritional composition of dehulled and defatted African locust bean seed (Parkia biglobosa )

Abstract: The nutritional and anti-nutritional composition of the African locust bean (ALB) was evaluated, with the aim of providing data that will guide the effective utilization of it under exploited tropical legume in food applications. Seeds of the African locust bean were depulped, dehulled, dehydrated and defatted. Chemical analyses were carried out using standard methods. Anti-nutritional factors, mineral analysis, fatty acid composition and free amino acid composition were also determined. The results obtained showed it to be a good source of potassium and phosphorus. A high unsaturated-saturated fatty acid ratio was observed, with linoleic acid having the highest level. Unlike most other legumes, it has appreciable quantity of sulphur-containing amino acids and thus ideal for the fortification applications with various food formulations.

Nitric oxide: A ubiquitous signaling molecule with diverse role in plants

Abstract: Nitric oxide (NO) is a gaseous di-atomic radical, readily diffusible through biological membranes and readily soluble in water is having a wide array of physiological, biochemical and molecular events in animals, plants and microbes. NO reacts directly with metal complexes and other radicals and indirectly as a reactive nitrogen oxide species with DNA, proteins, and lipids. In animals, NO is well established as a signaling molecule and is synthesized by multiple forms of nitric oxide synthase (NOS) enzyme from L-arginine. NO functions in almost all tissues and interacts with multiple target compounds in neurotransmission, vascular smooth muscle relaxation, and platelet inhibition. In plants, NO is synthesized through different enzymatic and non-enzymatic pathways, and play a diverse role in maintaining the functional homeostasis in normal (unstressed) systems as well in the protection against biotic and abiotic stresses. The present knowledge on the biochemistry of evolution, localization, mode of action and signaling of NO in plants shows that NO is one of the versatile molecule which can be transported easily to any compartment in the plant cell and elucidate its impact through various signal transduction pathways. The literature available is vast. This review deals with the biosynthesis, detection and estimation methods used in plants, translocation and detoxification, and role of NO in plants. Emphasis is given to the role of NO as a signal regulating molecule in plants. Key words: Nitric oxide (NO), nitric oxide synthase (NOS), gene regulation, senescence, synthesis, signal transduction, plant growth, development, stress, programmed cell death, localization, detoxification, movement.

Soil physicochemical properties under Acacia senegal varieties in the dryland areas of Kenya

Abstract: Acacia senegal is a multipurpose drought-tolerant tree or shrub legume and is commonly used in agroforestry systems in sub-Saharan Africa for gum arabic production and soil fertility improvement. Despite its wide distribution in Kenya, there has not been exhaustive evaluation on the effects of the extant varieties (kerensis, leiorhachis and senegal) on soil properties under their canopies for sustainable utilization of the species. Three sites in the drylands of Kenya representing the three varieties were selected for assessment. Soil samples were collected under tree canopies at a depth of 0 to 25 cm and were compared with the soils from the open canopies. There were significant differences in soil physicochemical properties among the three varieties (P<0.05 and P< 0.01). Soil nutrients under the canopies were higher than in the open canopies mainly due to effects of litter accumulation. The three varieties have beneficial effects on soil nutrient status in their natural ecosystems and would most likely improve crop productivity in agroforestry systems as well as enhance herbage productivity in the rangelands. The varieties growing under different soil types may have an effect on their gum Arabic production and quality. Key words: Acacia senegal varieties, soil nutrients accumulation, sustainable utilization.

Seedbed preparation influence on morphometric characteristics of perennial grasses of a semi-arid rangeland in Kenya

Abstract: Semi-arid rangelands in Kenya are an important source of forage for both domestic and wild animals. However, indigenous perennial grasses notably Cenchrus ciliaris (African foxtail grass), Eragrostis superba (Maasai love grass) and Enteropogon macrostachyus (Bush rye grass) are disappearing at an alarming rate. Efforts to re-introduce them through restoration programs have often yielded little success. This can partly be attributed to failure of topsoil to capture and store scarce water to meet germination and plant growth requirements. A study was undertaken in the semi-arid environment of eastern Kenya to determine the effects of land treatment on morphometric characteristics of E. superba, C. ciliaris and E. macrostachyus. Seed viability of the grasses was estimated by germination tests. Land treatments involved soil ripping using a tractor and hand-clearing. Thirty-five plants were randomly selected per sub-plot and tagged for sampling. Morphometric characteristics of the grass species were measured weekly. Aboveground biomass was estimated by harvesting standing biomass three months after establishment. Seed viability tests showed significant differences (p<0.05) among the three grass species. This was attributed to intrinsic properties of the grass seeds such as dormancy and tegumental hardness. Seedling survival, foliage cover, plant height, leaf and tiller numbers, and aboveground biomass were significantly higher in ripped plots than hand-cleared plots. It was concluded that soil disturbance influences plant morphometric characteristics and plays an important role in the success rate of restoration attempts in semi-arid rangelands.

Ethnobotanical survey of some Cameroonian plants used for treatment of viral diseases

Abstract: In this study, five species (Enantia cholorantha Oliv., Pteleopsis hylodendron Mildbr.and Spathodea campanulata P. Beauv., Costus afer Ker-Gawler and Mormodica charantia L.) belonging to five families were used for treatment of viral diseases including chicken pox, measles, influenza, shingles and viral hepatitis. The ethnobotanical survey of plant medicine was conducted in the Centre and South regions of Cameroon. The study aim was to obtain information on the use of plants in the treatment of viral diseases, the plant organs used, method of preparing herbal antiviral remedies and how it is administered, with a view to contribute to the search of new natural antiviral medicines. Results showed that traditional prescription of viral diseases generally included drinking, purging and steam bathing of the aqueous herbal preparations until symptoms of the disease disappear. This study shows the need for the enlightenment of traditional healers and the public in general on selective use of plants for the treatment of viral diseases. Key words: Ethnobotanical survey, viral diseases, medicinal plant, traditional healers.

Investigations on the phytochemical activities and wound healing properties of Adhatoda vasica leave in Swiss albino mice

Abstract: Adhatoda vasica has been used in many ayurvedic formulations. In order to evaluate the wound healing activity of A. vasica, five different solvent extracts were prepared from the leaves of the plant. Methanol, ethanol, ethyl acetate, chloroform and hexane were used for the extraction of the active ingredients. Excision wound model on Swiss albino mice was used to assess the wound healing activity of the leaves. Remarkable wound healing activity was observed with the ointment formulation of the methanol extract at 1% concentration. Wound contraction was calculated as percentage of the reduction in wound area. A specimen sample of tissue was isolated from the healed skin of each group of mice for the histopathological examination. The results of histopathological examination also supported the outcome of excision wound models. Hematoxylin and Eosin stained sections andVan Gieson’s stained sections were checked for collagen deposition. Toluidine blue stained sections were checked for metachromatic staining of mast cells. The present study demonstrated that the aerial parts of A. vasica promote wound healing activity in mice as a preclinical study. Key words: Adhatoda vasica, phytochemical analysis, excision wound model, wound healing activity, histopathological examination.

Phytochemical screening on four edible legumes ( Vigna subterranean, Glycine max, Arachis hypogea, and Vigna uniguiculata ) found in eastern Nigeria

Abstract: The results of the phytochemical screening carried out on the seeds of Vigna subterranea (Bambara groundnut), Glycine max (Soya beans), Arachis hypogea (Groundnut) and Vigna uniguiculata (Black eyed peas) showed the presence of useful phytonutrients. The results showed that V. subterranea contained the highest percentage of alkaloids (0.41%) while A. hypogea showed the lowest yield of alkaloid (0.25%). V. uniguiculata had the highest saponin content with (0.44%) while A. hypogea with the lowest (0.25%). The highest yield of flavonoids was found in V. uniguiculata with 0.33% while the lowest yield was obtained in A. hypogea with 0.18%. The highest phenols yield were obtained from V. subterranea with 0.36% while G. max showed the lowest with 0.26%. The percentage of tannins was highest in V. uniguiculata but lowest in A. hypogea . The results of the phytochemical screening on the four species of legumes were discussed in relations to their usefulness to mankind.

Optimization of optimum condition for phytic acid extraction from rice bran

Abstract: Phytic acid is one of the bioactive compounds that are being intensively studied to evaluate their effects on health. This study was carried out to determine the optimum condition for phytic acid extraction from rice bran. Three main parameters were considered to optimize the condition for phytic acid extraction; different types of extracting solvent, length of extraction time and influence of different pH adjustment. Three acidic solutions were selected and were trichloroacetic acid (TCA), hydrochloric acid (HCl) and sulphuric acid (H2SO4). The results showed that 5% of H2SO4 in pH 0.6 and after 30 min of extraction time gave the highest amount of phytic acid compared to 10% of TCA and 3% of HCl. The content of phytic acid in rice bran ranged from 0.22 to 2.22% for the different parameters optimized. Different methods produced different content of phytic acid from rice bran. Therefore, 5% of H2SO4 in pH 0.6 and 30 min of extraction time was the best condition for the optimum production of phytic acid. Key words: Phytic acid, rice bran, extraction, optimization, purification, HPLC.

Studies on cellulose degrading bacteria in tea garden soils.

Abstract: Cellulose degrading bacteria of tea garden soil were isolated, screened in vitro and its characterization, in relation to cellulase activity, was studied. Among the 25 isolates, the five strains showed higher enzyme activity when compared to other strains. Cellulase activity was expressed at a higher level by strain CDB 12 when blotting paper was used as a cellulose source in comparison with the other two substrate sources incorporated with minimal salt medium and followed by CDB 13 and CDB 21 in blotting paper. Maximum growth of cellulose degradation bacteria (CDB) was recorded at 30°C and pH 7.0. Among the carbon sources tested, maximum growth was observed in glucose amended mineral salts medium followed by fructose and maltose. Ammonium sulphate, ammonium nitrate and potassium nitrate were good nitrogen sources for better survival of CDB isolates. The biomass were continuously removed and placed as such into the tea field, then native and proven CDB strains were applied and they played an important role on the degradation of harvested biomass, which required replenishment to maintain the sustainable productivity of tea. Key words: Cellulase, cellulose degrading bacteria, tea.

Evaluation of tomato ( Lycopersicon esculentum L.) variety tolerance to foliar diseases at Kenya Agricultural Research Institute Centre-Kitale in North west Kenya

Abstract: Most vegetable cultivar evaluation trials focus on yield and quality attributes. However, disease tolerance is not routinely evaluated along with other parameters. The objective of this study was to evaluate new tomato cultivar for yield, quality and tolerance to foliar diseases. The most ubiquitous and devastating pathogen that infects tomatoes in the North rift Kenya is Phytophthora infestans that causes late blight and Alternaria solanithat causes early blight. There are several disease management practices that can be implemented to manage this disease including rotation, mulching, spacing, fungicide applications, and use of tolerant varieties. This study aimed at testing different varieties. Six new tomato cultivars, TKA143-33, TKA158-6, TKA193-28, TKA155-18, TKA193-2, TKA195-43 alongside a local check, CALJ were evaluated. The trial was laid out in completely randomized Block design (RCBD) layout replicated four times. The results showed that there were significant differences among varieties during the long season but not short rain season on yield. The local check CAL-J gave the least yield. There was low incidence of foliar diseases on the newly introduced varieties. This suggests that some of the new varieties could be good candidates for long and short season production seasons. Key words: Tomato, variety, on-station trial, disease tolerance, evaluation Kenya.

Influence of rooting media and indole-3-butyric acid (IBA) concentration on rooting and shoot formation of Warburgia ugandensis stem cuttings

Abstract: This study investigated the influence of different rooting media and indolebutryic acid (IBA) hormone concentration on root and shoot development in stem cuttings ofWarburgia ugandensis. Stem cuttings were treated with three different levels (0.3, 0.6 and 0.8% w/w) of IBA concentration (including a control- no IBA hormone) and propagated in three rooting media (milled pine bark, top forest soil and sand) under non-misting propagators. Data on root and shoot development, callusing, number and length of roots and shoots were analyzed using analysis of variance (ANOVA) and Chi square test. Callusing, root and shoot development were significantly (p<0.05) influenced by rooting media and IBA concentration. Milled pine bark and 0.8% w/w IBA concentration gave the highest percentages of stem cuttings that callused, rooted and shooted (38, 37, 41% and 57, 41, 59%), respectively. Similarly, milled pine bark and 0.8% w/w IBA concentration gave the greatest number and longest roots and shoots per stem cutting. Vegetative propagation of W. ugandensis through stem cuttings can be appropriately achieved by treating the cuttings with 0.8% w/w IBA hormone using milled pine bark as a growth medium. Key words: Warburgia ugandensis, indolebutryic acid (IBA), vegetative propagation, callusing, rooting, milled pine bark.

Distribution, Biology and Ecology of Parthenium hysterophorus L. (Congress Grass) an invasive species in the North-Western Indian Himalaya (Himachal Pradesh)

Abstract: Parthenium hysterophorus L. is a native plant of sub-tropical America and it is rapidly invading in the North-Western Indian Himalaya (Himachal Pradesh), from last two decades onwards. Here, it invaded up-to 2000 m altitude from mean sea level and drastically effecting native plant resources in the invaded habitats. The density and dominance of the P. hsterophorus has been higher in the summer and was nearly absent during the winter season in the NW Himalaya. The average height of the plants of P. hysterophorus was recorded up-to 2.09 ± 0.27 m and its root system deep up-to 17.32 ± 4.03 cm below the ground level. It produced an enormous number of seeds which will help in its invasion in to various habitats. It was measured that one single plant of Parthenium produced more than 7397 ± 81.42 seeds during one season. The seeds were lighter in weight and were 2.31 ± 0.02 mm in length and 1.03 ± 0.01 mm in width. In the NW Himalaya P. hysterophorus completed its two life cycles in one year, that is, from March to June and from July to November. Key words: Invasive species, North-Western Himalaya, Parthenium hysterophorus

Effect of calcium, magnesium, sodium and potassium on farm plantations of various agroeclogical zones of Punjab, Pakistan

Abstract: The immense impact of trees in the development of a country cannot be denied and over-emphasized Pakistan has a narrow forest resource base extending over only about 48% (459% excluding farmland plantations) of its area, which is insufficient to provide the material needs for the growing population, expanding and to retard and arrest the ongoing environmental and ecological degradation process Based on physiographic, climate and ecology, Pakistan is divided into nine major ecological or vegetative zones, which are further sub-divided into 18 habitat types, an arrangement for the development of protected areas system in terms of representative ecotypes During the survey of farm plantations, about 400 soil samples were collected and their physical and chemical analysis was conducted for the comparison of the four agro ecological zones of the Punjab Province of Pakistan with regards to agroforestry A comparison of the characteristics of soils taken from various farm plantations necessitated a prior evaluation of their calcium magnesium, sodium and potassium in order to ascertain whether the soils were similar or not In case of agroforestry, the type of soil is one of the major factors for the classification of different suitable species of plants The results of the soil analysis of various agro ecological zones and the consequent recommendation of the associated suitable species, aids the agrofarmers to pick out the best possible option Key words: Soil analysis, agro-ecological zones, agroforestry, calcium magnesium,sodium, potassium

Seasonal variation of fixed and volatile oil percentage of four Eucalyptus spp. related to lamina anatomy

Abstract: This experiment was conducted during the four seasons: Spring, summer, autumn and winter of two successive annual cycles; 2008/2009 and 2009/2010 (starting from May 2008). Four Eucalyptus species were under investigation; Eucalyptus camaldulensis Dehnh., Eucalyptus cinerea F. Muell. ex Bentham, Eucalyptus citriodora Hook. and Eucalyptus globulus Labill. Seasonal variations in the amount of fixed and volatile oils in Eucalyptus spp. matured leaves were investigated. It was determined that the amount of total lipids and essential oils significantly varied by the seasons (P < 0.01). The amount of total lipids in Eucalyptus spp. reached its peak mostly in spring. But the amounts of essential oils in different species were determined to be higher in summer, autumn and spring seasons, than in winter. Furthermore, the amount of total lipids and essential oils was higher in E. camaldulensis and E. cinerea than in other species. The anatomical investigation in the four studied Eucalyptus species, in relation to lipids percentage indicated that, the best lipids percentage amounts in this study were exhibited in E. cinerea and E. camaldulensis, for spring and winter; and were in agreement with these species highest lamina thickness. In general, fluctuation in lipids percentage is more correlated to the internal structure of lamina (duct average diameter, ducts total numbers, and open ducts numbers) in the same season; whereas, among seasons, it is thought that metabolism contributed more greatly. Cuticle thickness is true correspondence to seasonal environmental fluctuation, since it increases in all species, by shifting up from spring to summer then decrease to winter. Essential oils secretion which coincided with lipids percentage may be due to environmental stress influence over metabolism rather than structural adaptation. Key words: Eucalyptus, seasons, fixed and volatile oils, lamina, anatomy, glands.

Diversity of landraces, agricultural practises and traditional uses of watermelon (Citrullus lanatus) in Mozambique

Abstract: ��������� � �� ���������� A survey was carried out in three provinces of Mozambique with different agroecological conditions to document traditional knowledge related to cultivation and use of indigenous watermelons, and to describe the diversity of landraces within the country. Semi-structured interviews were used to collect information at the household level or in farmers’ watermelon fields. Watermelons were intercropped with the main cereals, mainly sorghum in the driest areas and maize in the more humid areas. Three main types were found: A dessert type with sweet, white to red, spongy flesh, a seed type with white either firm or spongy flesh, and a cooking type with yellow, firm flesh. Watermelon was an important food item consumed before harvest of cereals in the surveyed areas. Sweet dessert types were marketed in both local and urban areas. Only local landraces were cultivated, mostly from farmer-saved seed. Primary in-situ description of fruit and seed characters revealed a considerable variation. Significant differences were found among provinces for rind thickness, flesh colour, and seed size. This study highlighted that traditional knowledge related to the cultivation and use of watermelons, and that indigenous landraces persist in Mozambique.

Introgression of Pythium root rot resistance gene into Rwandan susceptible common bean cultivars

Abstract: A breeding scheme was carried out to introgress resistance genes to bean Pythiumroot rot in various commercial varieties grown in Rwanda. The achieved crosses were performed between three selected susceptible varieties (R617-97A, RWR 1668 and Urugezi) which are adapted to the various ecological production zones of Rwanda and two known sources of resistance to Pythium root rot(RWR719 and AND 1062). Following each inter varietal hybridization generation, a series of 4 successive back-crosses was achieved by using the susceptible parents as the initial parent lines to be improved for their respective behavior to Pythium root rot disease. At each back-cross generation, the PYAA 19800 SCAR marker linked toPythium root rot resistance in the two sources of resistance (varieties RWR 719 and AND 1062) was used to identify and to proceed to early selection of progenies possessing the gene of interest. The target materials serving for the molecular analyses were prepared from young trifoliate leaves of 2-weeks bean plantlets. It was observed that at each back-cross generation, there were variable proportions of plants exhibiting presence of the resistance gene according to the SCAR marker profiles. In addition to that observation mainly based to molecular profile, it was also revealed that the proportion of bean seeds having the same color as the susceptible parent line was increasing progressively. Finally, to assess if the individual plants exhibiting the SCAR marker are effectively resistant to the Pythium root rot disease, inoculation tests were carried out with a Pythium ultimum strain on each of them. This ultimate biological evaluation revealed that all the plants showing the SCAR marker were resistant to development of Pythium root rot symptoms after inoculation, confirming thus real introgression of the resistance characteristics through the breeding scheme adopted in our work. Key words: Phaseolus, vulgaris, Pythium, molecular, root rot, bean, genotype, resistance.

Effect of heavy metal pollutants on sunflower

Abstract: The aim of this present study was to assess the tolerance of pollutant elements (Co, Ni, Cd, Cr and Pb) on visible foliar symptoms, tissue concentration and some biochemical parameters in sunflower plants grown at 0.25 mM in soil pot culture. At equimolar concentrations (0.25 mM), Cd induced the most severe visual toxicity effects and exhibited maximum oxidative damage as observed by accumulation of ThioBarbituric Acid Reactive Substances (TBARS) and lower antioxidant capacity than the plants is exposed to Co, Cd, Cr and Pb. The study suggests that the degree of oxidative damage assessed by the manifestation of external visual toxicity effects, tissue concentration and alteration in biochemical parameters were found to be in the order Cd>Cr>Ni>Co>Pb. Key words: Sunflower, visible symptoms, TBARS, antioxidant, tissue concentration.

Kolanut production, processing and marketing in the South-eastern states of Nigeria

Abstract: Kola nut is an important economic crop in the South Eastern region of Nigeria. However, there were no contiguous kola farms in the South East, rather each homestead has about 2 to 15 kola trees scattered around the backyard. The land tenure system was observed to be the major constraint to kola production in large scale in the South East. Other limiting factors were poor nutrient status of the South Eastern soils, which have been heavily leached; the long gestation period of kola tree; the characteristic low yield of the crop; various pests, diseases and weeds (epiphytes) ravaging the plant. The non-inclusion of kolanut in the list of graded items for exportation by the Federal Government of Nigeria also contributes to its low production and marketing. Traditional methods of production, processing, storage and marketing peculiar to the South East are discussed.

Ethnobotanical survey of the uses of Annonaceae around mount Cameroon

Abstract: An ethnobotanical survey was carried out in eight villages around Mount Cameroon in the South West Region of Cameroon. It was focused on determining the uses of the members of the family Annonaceae in this region. Show and Tell Semi-structured Interviews employing a checklist of questions and direct observations were used. The results obtained enable the presentation of the rate of utilization of the members of that family in the study area. At least 70% of the 41 species recorded during field trips from the research area were found to be widely used in traditional medicine by local populations. Some 29 diseases were cured using 24 species. The bark and the wood of these species were the most commonly used plant parts. The check list and ethnomedicinal inventory was developed alphabetically by botanical name, followed by local name, part used, ethnomedicinal uses, mode of usage and information on species availability. Plant specimens were collected, identified, preserved, mounted and voucher was deposited in the Limbe Botanic Garden (SCA) for future references.

Cytogenetic and biochemical investigations to study the response of Vigna radiata to cadmium stress

Abstract: A study was carried out on root tips and leaves of Vigna radiata, 15 days old plantlets grown in nutrient Hoagland media were exposed to various levels of cadmium chloride (0.05, 0.10 and 0.50 mM) for 48 and 72 h. The plant tissues were analyzed for mitotic index, chromosomal variations, root-shoot ratio, leaf area, chlorophyll estimation, and the activity of nitrate content, nitrate reductase (NR), soluble protein and proline content. A number of chromosomal variations such as laggard chromosomes, anaphasic bridges, and unidistribution of chromatin material were observed in root tips. A reduction in mitotic index, root-shoot ratio, area of leaf and chlorophyll estimation was observed at all concentrations of cadmium. Moreover, activity of nitrate reductase (NR), nitrate content and soluble protein content was also found to be decreased. However, rate of proline content was found to be increased on increasing the concentration of cadmium. An increase in the levels of proline suggests its possible incorporation in synthesis of the phytochelatins and metallothioneins to sequester and combat Cd-stress. Key words: Vigna radiata, phytochelatins, cytogenetics, cadmium.

Chemical composition and antifungal activity of volatile components from woody terminal branches and roots of Tetraclinis articulate (Vahl.) Masters growing in Tunisia

Abstract: The chemical composition of the volatile fractions obtained from distilled woody terminal branches and roots of Tetraclinis articulata (Vahl.) Masters was identified by Gas Chromatography- Flame ionization detectors (GC-FID) and Gas Chromatography-Coupled with Mass Spectrometry (GC-MS). Twenty compounds represented 83.7% of the essential oil from woody terminal branches and 29.2% from the roots. Nonan-1-ol was the main constituent present in the second fraction of the essential oil from woody terminal branches with the highest percentage of 75.22. Monoterpene hydrocarbons viz: α-terpinene (3.04), δ-carene (1.17) and β-ocimene (1.09) were the main compounds. In the fourth fraction of the essential oil from roots, the major compounds detected were Bornyl acetate (16.63), Camphene (1.59) and γ-cadinene (2.86). This fraction was mainly rich in oxygenate compounds (20.25) and sesquiterpene hydrocarbons (6.84). Furthermore, the oils were tested for their antifungal activity against five phytopathogenic fungi. These oils from woody terminal branches and roots of T. articulata (Vahl.) Masters were found to possess antifungal activity. Key words: Antifungal activity, Cupressaceae, essential oil, Nonan-1-ol, Tetraclinis articulata (Vahl.) Masters.

Effects of gibberellic acid on sugarcane plants exposed to salinity under a hydroponic system

Abstract: A hydroponical experiment was conducted to evaluate the possible interaction of salinity (EC 0 and 9 dSm-1) and occurrence of exogenous gibberellic acid (GA3) (100 ppm) on imbalance and partitioning of nutrients in a popular sugarcane genotype (var. CP48-103) and its somaclonal tolerant variant. The results revealed that the uptake and partitioning of N, K+, Na+ and Cl- content were affected as a result of salinity, so salt stress induced the accumulation of toxic elements, namely: Na+ and CI-, and particularly in CP48-103. The tolerant variant performed better by maintaining higher N and K+. Some important parameters, namely shoot/root dry matter ratio and chlorophyll content decreased, while soluble sugars and protein content increased due to salt stress. Irrespective of the genotypes, supplementing GA3 (100 ppm) as foliar application play important role on imparting salt tolerance in terms of enhancing nutrient uptake, as well as the morphological and physiological aspects. The result of this study showed that inhibition of the growth of sugarcane plantlets by salt stress was removed by GA3. Key words: Sugarcane, salt stress, somaclonal variant, gibberellic acid.

A new strategy for complete identification of 69 grapevine cultivars using random amplified polymorphic DNA (RAPD) markers

Abstract: DNA marker is a useful technique that has immense power in plant cultivar identification, which used to be the first preferential utility of any newly developed DNA marker technique. However, DNA markers have not been utilized well in the practice of plant identification, for which the bottleneck is no analysis methods available that can make the identification of plants with DNA marker easy, efficient and practical. We developed a novel approach called cultivar-identification-diagram (CID) strategy that can facilitate the utilization of DNA marker in the separation of plant individuals in a much better, efficient, practical, and referable manner. A CID was manually constructed with an intention of providing the polymorphic maker generated from each polymerase chain reaction (PCR) for sample separation. In this study, a total of 69 important grape cultivars cultivated in China were successfully separated with random amplified polymorphic DNA (RAPD) marker through the CID analysis strategy, with only seven 11nt primers being employed. The utilization of the CID of these 69 grapevine cultivars was also verified by identification of two randomly chosen groups of cultivars among the 69. The main advantages of this identification strategy include fewer primers used, and separation of all the cultivars from each other by the corresponding primers marked in the right position on the CID. This grapevine CID can provide information to separate any grapevine cultivars among the 69 studied, which can definitely be of great help in grapevine cultivar identification for cultivar-right-protection and to the grapevine nursery industry in China. Key words: Grapevine, cultivar identification, new strategy.