Participatory plant breeding approach for host plant resistance to bean fly in common bean under semi-arid Kenya conditions     

Pascal P. Okwiri Ojwang’  Rob Melis  Josephine M. Songa  Mwangi Githiri  Charles Bett 《Euphytica》2009,170(3):383-393

Common bean (Phaseolus vulgaris L.) is the most important legume crop in Kenya. It is cultivated across a wide range of agro-ecologies which include high potential and marginal areas. Eastern Kenya alone, largely semi-arid, accounts for 35% of the country’s total bean production. Bean farmers mainly small-scale have limited access to quality seed, chemical pesticides and fertilizer. Therefore, bean yield under on-farm conditions still remains below 500 kg ha⁻¹ while the potential is about 1,200 kg ha⁻¹ under semi-arid conditions. To asses the farmers’ views on bean varieties and a key insect pest and associated constraints contributing to yield loss, research was undertaken. The research included survey to quantify the yield loss and Participatory Rural Appraisal to determine the level of adoption and criteria for variety choice in semi-arid eastern Kenya (SAEK). The results show that farmers consider drought and insect pest problems as main causes for low yields. The adoption rate for improved varieties is high but self sufficiency in beans stands at 23% in the dry transitional (DT) agro-ecology and at 18% in the dry mid-altitude (DM) agro-ecology, respectively. This could be attributed to low adaptability since most of the improved varieties grown were selected for high potential areas but now found in marginal areas. Drought, earliness, yield stability, and insect pest resistance are the main reasons for choice of varieties by farmers. Bean fly (Ophiomyia sp.) was identified as one of the key crop pests of beans limiting yield. Besides, African bollworm (Helicoverpa armigera) and bean aphid (Aphis fabae) were ranked higher. Due to limitations of the conventional breeding approach, a participatory plant breeding approach is suggested so as to provide an opportunity to develop insect pest resistant varieties adapted to the SAEK region.  相似文献   

Antibacterial activity in microalgae cultures     

Foteini Kokou  Pavlos Makridis  Maroudio Kentouri  Pascal Divanach 《Aquaculture Research》2012,43(10):1520-1527

Five cultures of microalgae (Chlorella minutissima, Tetraselmis chui, Nannochloropsis sp., Arthrospira platensis and Isochrysis sp.) with no culturable bacteria were tested for their ability to inhibit the growth of six Vibrio bacterial strains (V. parahaemolyticus, V. anguillarum, V. splendidus, V. scophthalmi, V. alginolyticus and V. lentus). The influence of light on the antibacterial activity of the microalgae was investigated. All microalgae cultures inhibited the growth of bacteria compared with the control treatments (P < 0.05), and their antibacterial activity was not influenced by the presence or absence of light. In the control groups, the numbers of bacteria increased exponentially during the experimental period in the absence of microalgae cells demonstrating that the bacterial cells were able to utilize the growth medium of microalgae cultures. The present results may explain the low levels or absence of Vibrio strains in microalgae cultures, and the positive effect of addition of microalgae in rearing of fish larvae, and implicate the production of antibacterial compounds by microalgae cells.  相似文献   

The application of tannic acid to the elimination of egg stickiness at varied moments of the egg swelling process in pikeperch,Sander lucioperca (L.)          下载免费PDF全文

Daniel Żarski  Sławomir Krejszeff  Dariusz Kucharczyk  Katarzyna Palińska‐Żarska  Katarzyna Targońska  Krzysztof Kupren  Pascal Fontaine  Patrick Kestemont 《Aquaculture Research》2015,46(2):324-334

The aim of this article was to analyse the process of pikeperch, Sander lucioperca, egg swelling and to apply tannic acid to eliminate egg stickiness at different moments of the swelling process on artificially obtained eggs. The first experiment involved observation of egg swelling process and the second determined the effect of temperature (12, 14 and 16°C) on the egg swelling rate. The third experiment involved elimination of egg stickiness in a tannin solution (0.75 g L^?1) where eggs were submerged in a solution for 0.5, 1, 2 and 5 min – 5, 10, 15, 20, 25 and 30 min following gamete activation. The results indicate that the pikeperch egg swelling process lasts 30 min. It was found that the temperature did not affect the process duration. The results of the third experiment showed that the effectiveness of tannic acid application in egg stickiness elimination increases with time. The best result was obtained in groups of eggs submerged for 1 and 2 min (86.5% and 80.5% of larvae were obtained respectively) 30 min following the gamete activation. The results presented in this study for the first time indicate the possibility of highly effective procedure of egg stickiness elimination with tannic acid in pikeperch aquaculture.  相似文献   

PESO: a modelling framework to help improve management strategies for epidemics – application to sharka          下载免费PDF全文

Coralie Picard  Loup Rimbaud  Pascal Hendrikx  Samuel Soubeyrand  Emmanuel Jacquot  Gaël Thébaud 《EPPO Bulletin》2017,47(2):231-236

The optimization of management strategies for plant diseases is a difficult task because of the complexity and variability of epidemic dynamics. Thanks to their ability to numerically simulate many scenarios, models can be used to estimate epidemiological parameters, assess the effectiveness of different management strategies and optimize them. This article presents the PESO (parameter estimation–simulation–optimization) modelling framework to help improve plant disease management strategies. This framework is based on (i) the characterization of the epidemic dynamics to estimate key epidemiological parameters, (ii) the use of spatially explicit models to simulate epidemic dynamics and disease management, and (iii) the use of numerical optimization methods to identify better management strategies. This approach is generic and can be applied to many diseases. The work presented here focuses on sharka (caused by Plum pox virus), which has a worldwide impact on the Prunus industry, and is associated with huge disease management costs in many countries, especially in France.  相似文献   

Removal of Phenolic Compounds from Aqueous Solutions Using Sludge-Based Activated Carbons Prepared by Conventional Heating and Microwave-Assisted Pyrolysis     

Glaydson S. dos Reis  Matthew A. Adebayo  Carlos H. Sampaio  Eder C. Lima  Pascal S. Thue  Irineu A. S. de Brum  Silvio L. P. Dias  Flavio A. Pavan 《Water, air, and soil pollution》2017,228(1):33

Sludge-derived activated carbons (ACs) were prepared by conventional heating and microwave pyrolysis. The ACs were characterized using several analytical and functional techniques and used for removal of six phenolic compounds from aqueous solutions. The adsorbents exhibited similar features and possessed hydrophobic surfaces. The ACs were assigned mesoporous materials, with specific surface areas of up to 641 and 540 m² g^?1 for CAC-500 and MAC-980, respectively. The preliminary results indicated that phenol removal onto the ACs increased in the order: m-cresol?<?phenol?<?o-cresol?<?2-chrorophenol?<?2-nitrophenol?<?hydroquinone. Hydroquinone exhibited the highest adsorption capacity and was chosen to continue the remaining part of the experimental work—kinetic and isothermal studies. The adsorption kinetic and isotherm data were well described by the Avrami fractionary order and Redlich–Peterson models, respectively. The maximum amounts (Q _max) of hydroquinone adsorbed at 25 °C were too high, reaching 1218.3 and 1202.1 mg g^?1 for CAC-500 and MAC-980, respectively. The mechanism of adsorption was proposed in this work, and it was suggested that donor–acceptor complex and π–π interactions play major roles in the adsorption process. The adsorbents were also tested on simulated effluents. The two ACs displayed good efficiency for the treatment of industrial simulated effluents.  相似文献   

Morphology and foliar chemistry of containerized <Emphasis Type="Italic">Abies fraseri</Emphasis> (Pursh) Poir. seedlings as affected by water availability and nutrition     

Pascal Nzokou  Bert M. Cregg 《Annals of Forest Science》2010,67(6):602-602

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• We present the results of a two-year (2007–2008) greenhouse study investigating the effect of water availability and nitrogen fertilization on the growth, biomass partitioning, and foliar nutrient content of Abies fraseri (Pursh) Poir.  相似文献    57. The Advantages of Combining Low‐Density Lipoproteins with Glutamine for Cryopreservation of Canine Semen      D Bencharif  L Amirat  O Pascal  M Anton  E Schmitt  S Desherces  G Delhomme  M‐L Langlois  P Barrière  M Larrat  D Tainturier 《Reproduction in domestic animals》2010,45(2):189-200 Twenty sperm samples from five dogs were frozen in liquid nitrogen at ?196°C in 16 different media, two control media containing 20% egg yolk and 6% low‐density lipoproteins (LDL); 10 test media containing 6% LDL (the active cryoprotective ingredient of chicken egg yolk) combined with 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mmol of glutamine respectively at 4%, 5%, 7%, and 8% LDL. Following thawing, sperm mobility was assessed using an image analyser, HAMILTON THORN CERROS 12. The percentage of mobile spermatozoa was 62.05% in the 6% LDL + 20 mmol glutamine medium compared with 48.90% in the egg yolk‐based medium (p < 0.05) or 57.55% for the 6% LDL medium (p < 0.05). Furthermore, in most cases, the motility parameters (average path velocity, curvilinear velocity, straight line velocity) in the 6% LDL + 20 mmol glutamine medium, were superior, to a statistically significant extent, to those in the control media. Finally, the 6% LDL + 20 mmol glutamine combination provides spermatozoa with better protection during freezing than egg yolk or the 6% LDL medium alone in terms of acrosome integrity (fluorescein isothiocyanate–Pisum sativum agglutinin test: p < 0.05), the flagellar plasma membrane (hypo‐osmotic test: p < 0.05 for 6% LDL), the DNA (acridine orange test; no significant difference) and the integrity of the acrosome (Spermac® test: no significant difference).  相似文献    58. 矮小型肉种鸡的新看法      孙华 《国外畜牧学(猪与禽)》2010,30(4):22-24 "矮小型"肉种鸡进入市场已几乎有40年的历史,并且一直以来在家禽行业内存有争论,一些人表示支持利用这一鸡种,但也有些人表示对其不感兴趣。两者往往都夸大其有利或不利的一面,或者更倾向于考虑市场行情和环境条件的不同。让我们以实事求是的态度看待此鸡种!  相似文献    59. 橡胶树品种热研88-13易碎胚性愈伤组织的诱导及其植株再生   总被引：1，自引：0，他引：1   李哲  孙爱花  黄天带  周权男  戴雪梅  黄华孙  林位夫  Ludovic Lardet  Pascal Montoro 《热带作物学报》2010,31(12):2166-2173 以高产优质橡胶品种热研88-13的幼嫩种子内珠被为外植体材料,对愈伤组织诱导培养基和继代培养基中的影响因素如植物生长调节剂的种类和浓度、钙离子浓度等进行了研究。经过连续6个月的继代选择培养,逐渐诱导出易碎的胚性愈伤组织,适宜的易碎胚性愈伤组织诱导培养基为:MH基本成分,添加0.5 mg/L KT,2.0 mg/L 2,4-D,11.0 mmol/L CaCl2,80.0 g/L蔗糖和2.0 g/L Phytagel。组织学切片证明长期继代培养的易碎胚性愈伤组织维持了胚性的状态。取继代培养2 a多的易碎胚性愈伤组织诱导体细胞胚的形成,得到了16 000多个体细胞胚。将这些胚进行进一步的转移培养,得到了115株再生植株。  相似文献    60. Inter-laboratory comparison of four RT-PCR based methods for the generic detection of pospiviroids in tomato leaves and seeds      Thibaut Olivier  Vaidevutis Šveikauskas  Elisabeth Demonty  Kris De Jonghe  Pascal Gentit  Mojca Viršček-Marn  Sabine Grausgruber-Gröger  Sébastien Morio  Francesco Faggioli  Michèle Visage  Frédéric Fauche  Maria Gusina  Marta Luigi  Helena Lasner  Irena Mavrič-Pleško 《European journal of plant pathology / European Foundation for Plant Pathology》2016,144(3):645-654   相似文献    [首页] « 上一页 [1] [2] [3] [4] [5] 6 [7] [8] [9] [10] [11] 下一页 » 末  页»