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991.
G. A. Owusu D. Nyadanu K. Obeng-Antwi R. Adu Amoah F. C. Danso S. Amissah 《Euphytica》2017,213(12):287
Maize (Zea mays L.) is the most important cereal crop produced in Ghana. However, yield of the crop is generally low, producing just about 1.7 t/ha. The low yield is attributed to continuous use of local/unimproved varieties. Generally, hybrid varieties have proven to out-yield the local/unimproved varieties due to improved vigour. Development of hybrid varieties depend on good understanding of combining ability and inheritance of important quantitative traits such as grain yield (GY). 45 half-diallel crosses generated from 10 extra-early maturing yellow inbred lines were evaluated in 2015 under rain-fed conditions. The objectives were to determine the genetic control, breeding value and estimate heritability for GY and agronomic traits of the inbred lines under contrasting growing environments in Ghana. General combining ability (GCA) and specific combining ability (SCA) were important in the inheritance of GY and agronomic traits of the inbred lines. However, GCA was more important than SCA across environments to suggest that additive gene action was more important than non-additive gene action in the inheritance of GY and agronomic traits in the inbred lines. High broad-sense heritability, for GY and other agronomic traits indicated preponderance of additive gene action in trait expression, thus, selection based on phenotypic expression could be feasible. Inbred lines P1, P4 and P8 were good combiners for high GY. The genotype, P4 × P8, was identified as the ideal and most yielding single-cross hybrid across research environments and should be further tested on-farm before commercialization. 相似文献
992.
Vittorio Rossi Elisabetta Pattori Riccardo Bugiani 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(2):147-159
The dynamics of the production of Stemphylium vesicarium conidia and Pleospora allii ascospores from different inoculum sources on the ground were compared in a model system of a wildflower meadow mainly composed
of yellow foxtail, creeping cinquefoil and white clover. The meadow was either inoculated (each October) or not inoculated
with a virulent strain of S. vesicarium, and either covered or not covered with a litter of inoculated pear leaves. Spore traps positioned a few centimetres above
the ground were exposed for 170 7-day periods between October 2003 and December 2006. Ascospores and conidia were trapped
in 46 and 25% of samples, respectively. Ascospore numbers trapped from the pear leaf litter were about five times higher than
those from the meadow, while conidial numbers were similar from the different inoculum sources. The ascosporic season was
very long, with two main trapping periods: December–April, and August–October; the former was most important for the leaf
litter, the latter for the meadow. The conidial season lasted from April to November, with 92% of conidia caught between July
and September. The fungus persistently colonized the meadow: the meadow inoculated in early October 2003 produced spores until
autumn 2006. The present work demonstrates that orchard ground is an important source of inoculum for brown spot of pear.
Thus, it is important to reduce inoculum by managing the orchard ground all year long. 相似文献
993.
Levente Kiss Alexandra Pintye Györgyi Zséli Tünde Jankovics Orsolya Szentiványi Yaser M. Hafez Roger T. A. Cook 《European journal of plant pathology / European Foundation for Plant Pathology》2010,126(4):445-451
Microcyclic conidiogenesis (MC), a process defined as the production of conidia on a spore without any, or only a minimal,
involvement of hyphal growth, has recently been reported in a little known powdery mildew species, Oidium longipes. To investigate whether this was an isolated case or it is a more general phenomenon in powdery mildew fungi, germinating
conidia of eight species of the Erysiphales were examined using light microscopy. The following species were included in this work: Erysiphe necator on grapevine, Blumeria graminis f. sp. hordei on barley, Podosphaera xanthii on cucumber, Erysiphe sp. on Ligustrum vulgare, O. longipes on Petunia x grandiflora, O. neolycopersici on tomato, Golovinomyces cichoracearum on Rudbeckia laciniata and Sawadaea sp. on Acer negundo. In all these species, up to 4% of the germinated conidia exhibited MC. Moreover, when colonies of E. necator and O. neolycopersici, on detached grapevine and tomato leaves, respectively, were treated with a conidial suspension of Ampelomyces, the intracellular pycnidia of these mycoparasites appeared in microcyclic conidiophores. This represents a yet undescribed
method of accelerating asexual reproduction in this mycoparasite. In the life cycle of powdery mildews, the importance of
MC is still not clear but it should be taken into consideration when conidial germination is studied on the host surface for
purposes such as epidemiology or species identification. 相似文献
994.
Responses of the endemic leguminous shrub Bauhinia faberi var. microphylla, to various soil water supply regimes were studied in order to assess water stress tolerance of seedlings. Two-month-old
seedlings were grown under water supply regimes of 100, 80, 60, 40, and 20% water field capacity (FC), respectively, in a
temperature and light-controlled greenhouse. Plant height and leaf number were measured monthly over a 4-month period, while
water use (WU), water-use efficiency (WUE), leaf relative water content (RWC), biomass production and its partitioning were
recorded at the end of the experiment. Seedlings exhibited the greatest biomass production, height, basal diameter, branch
number, leaf number, and leaf area when soil content was at 100% FC, and slightly declined at 80% FC. These parameters declined
significantly under 60% FC water supply, and severely reduced under 40 and 20% FC. RWC, WU and WUE decreased, while the ratio
of root mass to stem mass (R:S) increased in response to decreasing water supply. Water stress caused leaf shedding, but not
plant death. The results demonstrated that B. faberi var. microphylla seedlings could tolerate drought by reducing branching and leaf area while maintaining a high R:S ratio. However, low dry
mass and WUE at 40 and 20% FC suggested that the seedlings did not produce significant biomass under prolonged severe water
deficit. Therefore, before introducing B. faberi var. microphylla in vegetation restoration efforts, water supply above 40% FC is recommended for seedlings to maintain growth. 相似文献
995.
Blandine Marie Ivette Nacoulma Anne Mette Lykke Salifou Traoré Brice Sinsin Adjima Thiombiano 《Agroforestry Systems》2017,91(3):565-576
In sub-Saharan Africa, extraction for daily livelihood needs often results in uncontrolled exploitation of bark and leaves of valuable medicinal and fodder trees. However, overharvesting of bark and foliage can reduce fruit production and threaten reproduction. This study evaluates the impact of combined bark and foliage harvesting on the performance of fruit production of Afzelia africana in Burkina Faso. We compared fruit and seed production at different harvesting intensities. Data on fruit yields were collected by stratified random sampling of 91 trees with no, low, severe, and very severe harvesting intensities. The fruit production varied with harvesting intensity, tree size and number of branches. Fruit and seed quantity and quality decreased with increasing harvesting intensity. However, no significant difference was detected between trees without and trees under low harvesting. Trees of all size classes under very severe harvesting intensity had no fruits. Under low harvesting impact, large trees had twice as many fruits as the control, whereas fruits were reduced by half to 95 % for the small trees. High harvesting intensity is an unsustainable practice that should be completely prohibited in order to ensure longterm persistence of Afzelia africana. Low harvesting intensity should be allowed, but only on large reproductive individuals. 相似文献
996.
Aparicio-Fernández X Reynoso-Camacho R Castaño-Tostado E García-Gasca T González de Mejía E Guzmán-Maldonado SH Elizondo G Yousef GG Lila MA Loarca-Pina G 《Plant foods for human nutrition (Dordrecht, Netherlands)》2008,63(1):35-40
Jamapa bean is a black Phaseolus vulgaris variety rich in condensed tannins, anthocyanins and flavonols with interesting biological activities. The objective of this
work was to evaluate the antiradical capacity (ARC) of a Jamapa bean methanolic extract (BME) and some of the proanthocyanidin-rich
fractions derived from it, using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The effect of the BME on some proteins involved
in apoptosis on HeLa cells was also evaluated. A strong correlation between proanthocyanidin concentration in BME and antiradical
capacity was found, suggesting that these compounds contribute significantly to antiradical activity. BME was a better radical
scavenger than butylated hydroxytoluene (45.6 and 33.9% ARC at 400 μM, respectively). Two proanthocyanidin-rich fractions
obtained after a preliminary separation of the BME using Toyopearl (TP4 and TP6) exhibited a higher antiradical activity than
the parent extract. The treatment of HeLa cells with 35 μg BME/ml/24 h increased the expression of Bax and Caspase-3, pro-apoptotic
proteins (6.13 and 1.2 times for Caspase-3 and Bax, respectively). The mechanism of action of some proteins involved in apoptosis
was also evaluated, and the results suggest that black Jamapa bean could be an important source of polyphenolic compounds
with potential biological use as antioxidant and anticancer agents. 相似文献
997.
Hiromitsu Furuya Tsutomu Matsumoto Shin-ichi Fuji Hideki Naito 《Journal of General Plant Pathology》2003,69(2):115-119
Rice seedling growth, estimated by plant height and root development and discoloration, was better in pasteurized soil than
in unpasteurized soil obtained from a flooded rice field. Rice seedlings also grew better in sterilized soil modified by adding
roots harvested from the pasteurized soil than in soil modified by adding roots harvested from the unpasteurized soil. The
results demonstrate that seedling growth in the rice field soil was inhibited by soil microorganisms, even though no typical
symptoms such as seedling blight or damping-off appeared. Pythium aristosporum is suggested to be involved in the inhibition. Thus, it appears that inconspicuous restraint of rice seedling growth could
occur in soils of rice paddy fields.
Received: May 20, 2002 / Accepted: October 16, 2002
Acknowledgments The authors thank Dr. T. Ichitani, former professor at Osaka Prefectural University, for providing an isolate of Pythium aristosporum for comparison, and Mr. Mitsuaki Sato of Akita Prefectural College of Agriculture for technical assistance. 相似文献
998.
Ademola O. Olaniran Adhika Balgobind Ajit Kumar Balakrishna Pillay 《Journal of Soils and Sediments》2017,17(8):2019-2029
Purpose
Bioremediation of co-contaminated environments is difficult because of the mixed nature of the contaminants and the fact that the two components often must be treated differently. This study investigated the use of inorganic treatment additives, namely calcium carbonate (CaCO3), gypsum (CaSO4·2H2O), and disodium phosphate (Na2HPO4) to improve remediation of soil co-contaminated with 1,2-dichloroethane (1,2-DCA) and arsenic or cadmium.Materials and methods
The soil samples were collected from a specific site in the Westville area in Durban, KwaZulu-Natal, South Africa. Microcosms were set up by artificially co-contaminating the soil sample (100 g mixed with 75 ml of synthetic groundwater in sterile screw-capped 250-ml serum bottles) with 1,2-DCA + risk elements; As3+ (150 mg/kg); or Cd2+ (170 mg/kg). Thereafter, each microcosm was amended with either 5 g CaCO3, 2 g CaSO4·2H2O, or 1.12 g Na2HPO4 + 0.046 g NaCl, separately. The samples were analyzed for the degradation of 1,2-DCA using GC–MS, while total 1,2-DCA degrading bacterial populations were determined at different sampling times using a standard spread plate technique. Soil dehydrogenase and urease activities were also monitored during the experimental period using standard enzyme assays.Results and discussion
Addition of CaCO3 resulted in an approximately 2-fold increase in 1,2-DCA degradation in both the As3+ and the Cd2+ co-contaminated soil as compared to the co-contaminated soil without CaCO3. All the treatment additives were more effective in the As3+ co-contaminated soil resulting in 11.19, 9.25, and 5.63% increase in 1,2-DCA degradation in the presence of CaCO3, Na2HPO4 + NaCl, and CaSO4·2H2O, respectively, compared to the Cd2+ co-contaminated soil. The total 1,2-DCA degrading bacterial population increased in treated soils over time. Overall, soil dehydrogenase and urease activities were lower in the heavy metal co-contaminated samples compared to the treated soil. The inhibitory effect of heavy metal was less in As3+ co-contaminated soil for both CaCO3- and Na2HPO4 + NaCl-treated soil, with up to 7.92% increase in dehydrogenase activity obtained compared to soil co-contaminated with Cd2+.Conclusions
Results from this study indicate that treatment additives can be used to reduce bioavailable fractions of risk elements in the soil matrices, thereby limiting the toxicity of these risk elements to 1,2-DCA degrading microorganisms. Thus, this approach can be applied to enhance organic compound degradation in co-contaminated soil environments.999.
Yohei Nakamura Masahiro Horinouchi Mitsuhiko Sano Takuro Shibuno 《Fisheries Science》2009,75(6):1401-1408
Whilst the importance of seagrass beds as nurseries for coral reef fishes has been clearly recognized, the vast majority of
early studies on fish nursery habitats emphasized the close proximity of the latter to coral reefs. To determine the potential
nursery role of isolated seagrass beds, we investigated the degree to which juvenile emperor fishes (Lethrinidae) utilized
seagrass beds in the presence/absence of adjacent coral habitats at Ishigaki Island (southern Japan), such fishes being known
to use seagrass beds as nurseries. Seagrass beds in close proximity to coral habitats (distance between the two habitats of
50–200 m) had greater densities of lethrinid juveniles than those without adjacent coral habitats (2.5–4 km) for 3 different
sites investigated, although a significant difference was obtained only for 1 site. Juveniles of Lethrinus atkinsoni, L. obsoletus, L. harak, and L. nebulosus were observed in seagrass beds with and without adjacent coral habitats, whereas L. ornatus occurred only in the former. Overall, most lethrinid juveniles utilize seagrass beds irrespective of the presence of adjacent
adult coral habitat, suggesting that both types of seagrass beds would contribute to lethrinid adult populations. Therefore,
management efforts for lethrinid populations should be applied not only to contiguous coral-seagrass habitat systems but also
to isolated habitats. 相似文献
1000.