二倍体与四倍体刺槐组培苗形态和生理性状比较

为了比较二倍体与四倍体刺槐组培苗不同无性系之间的差异,本研究分别测定二倍体刺槐组培苗和人工诱导四倍体刺槐组培苗的形态及生理指标,并进行相关分析。结果表明,多数四倍体刺槐无性系的长势、抗逆性优于二倍体;二倍体与四倍体刺槐不同无性系以及不同形态、生理指标之间存在丰富的变异,其中四倍体刺槐的变异更为丰富;各测定指标之间存在较为复杂的相关关系,在选择育种时,需综合考虑。根据试验结果,结合育种目标,可选育出优良四倍体刺槐无性系,丰富刺槐种质资源,增加遗传多样性。本研究为刺槐倍性育种工作提供了理论依据和科学参考。     

Effects of dwarfing genes on yield and yield components under irrigated and rainfed conditions in wheat (Triticum aestivum L.)

Summary Near-isogenic tall (no dwarfing gene), semidwarf (Rht1 or Rht2) and dwarf (Rht1 + Rht2 or Rht3) spring wheat lines were evaluated for yield and yield components under irrigated and rainfed conditions. Under irrigated conditions, the dwarf and the semidwarf lines exhibited a significant yield advantage over the tall lines. Under rainfed conditions, the semidwarf lines outyielded the tall as well as the dwarf lines. Percent yield reduction in response to drought stress was highest with the dwarfs and lowest with the tall lines. Dry matter production of the tall lines and that of the semidwarf lines did not differ significantly and both produced significantly more dry matter than the dwarf lines under irrigated as well as rainfed conditions. Plant height and kernel weight decreased with increasing degree of dwarfness while number of kernels per spikelet, harvest index and days to heading increased under both moisture regimes. The dwarfing genes did not have any significant influence on number of tillers/m² and spikelets per spike in either moisture regime.     

Nutrient Dynamics: Effect on Cropping Behavior,Nutrient Profile and Quality Attributes of Pomegranate (Punica Granatum L.) Under Rainfed Agroclimatic Conditions

The study was carried out between 2008 and 2010 on 8-year-old pomegranate (Punica granatum L.) trees cultivar ‘Kandhari Kabuli.’ The potential efficiency of bio-organics used along with chemical fertilizers on cropping behavior, quality attributes, nutrient availability, physico-chemical, and biological properties of soil were investigated. Bioorganic nutrient sources, namely, vermicompost (VC), biofertilizers (BF), farm yard manure (FYM), and green manure (GM), along with chemical fertilizers was evaluated in 13 different treatment combinations. Conjoint treatment application of VC at 20 kg tree^?1, BF at 80 g tree^?1, FYM at 20 kg tree^?1, GM as sun hemp (Crotalaria juncea L.) along with 75% of the recommended dose of nitrogen–phosphorus–potassium (N–P–K) chemical fertilizers significantly resulted in maximum fruit set (52.03%) and fruit yield (34.02 kg tree^?1). All of the fruit quality characteristics were also improved significantly when compared to nitrogen–phosphorus–potassium (N–P–K) chemical fertilizers. This superior combination also enhanced physical-chemical and biological properties of the rhizosphere soil. Microbial biomass of in terms of Pseudomonas, total culturable soil fungi, Azotobacter chroococcum, actinobacteria, and arbuscular mycorrhizal (AM) fungi improved 385.57, 60.26, 134.19, 168.02, and 39.87%, respectively, over control. This combination also resulted in considerable greater concentration of leaf macro-and micronutrients: N (2.63%), P (0.25%), K (1.57%), iron (Fe; 197.87 mg kg^?1), copper (Cu; 14.65 mg kg^?1), zinc (Zn; 59.36 mg kg^?1), and manganese (Mn; 200.45 mg kg^?1).     

Interaction of soil microbial communities and phosphorus fractions under long-term fertilization in paddy soil

Understanding the impact of biological activities on the soil phosphorus (P) distribution under long-term fertilizer application can facilitate better soil P fertility management. Therefore, the primary objectives of this study were to investigate the effect of long-term (since 1981) fertilizer application on the soil P fractions and microbial community and to evaluate correlations between the microbial community structure and P distribution. The following treatments were implemented in a long-term field trial: no fertilization (CK), inorganic N and K (NK), inorganic P and K (PK), inorganic N, P and K (NPK) and manure+NPK (MNPK) fertilization. The study showed that the soil pH, soil organic carbon and total and available N and P concentrations were considerably higher in the MNPK treatment than in the CK treatment. The soil microbial biomass C, N and P concentrations were also significantly higher in the MNPK treatment than in the CK treatment. Among fertilization treatments, the β-1,4-glucosidase, α-1,4-glucosidase, urease, acid phosphatase and phosphodiesterase activities were the highest in the MNPK treatment. Compared to inorganic fertilization, the MNPK treatment increased the labile soil P fractions and decreased the residual soil P concentration. Continuous fertilization significantly affected the soil microbial composition. The total phospholipid fatty acid (PLFA) concentrations in the NK, PK, NPK and MNPK treatments were 23.3, 43.1, 48.7 and 87.7% higher, respectively, than in the CK treatment. A significant correlation was observed between the microbial community and soil P fractions. Moreover, the aggregated boosted tree (ABT) model showed that among the various soil biochemical properties, the total PLFA concentration was the factor that most influenced the active P pool, accounting for 35.4% of the relative influence of all soil biochemical properties examined. These findings reveal that combined manure and inorganic fertilizer application is a better approach than applying inorganic fertilizer alone for sustaining long-term P fertility by mediating soil biological activity.     

人工诱发条件下玉米自交系对红蜘蛛的抗性鉴定及抗感性分类

在人为控制和创造有利于玉米红蜘蛛发生、又能基本满足玉米正常生长发育需要的条件下,以来自国内外的74个重要玉米自交系为材料,进行了玉米自交系对红蜘蛛抗性的人工诱发鉴定。结果表明:不同的玉米自交系对红蜘蛛的抗性差异很大,其受害指数为0.06~0.91;叶片平均受害面积百分率与受害指数呈极显著正相关(r=0.97,P0.000 01)。这些自交系以其受害指数为基础,通过聚类分析划分为高抗、抗、中感、感和高感5个类群;自交系受害指数在类群间[高抗(0.11±0.02),抗(0.22±0.04),中感(0.35±0.03),感(0.49±0.05),高感(0.75±0.10)]差异极显著(P0.01)。在参试自交系中,ZH4改-1、BSSSS53-B、Q381等20个高抗红蜘蛛,KS2564、B47、1028S等19个抗红蜘蛛,掖478、冀35、PH6WC等18个中感红蜘蛛,郑58、B73、丹340等12个感红蜘蛛,昌7-2、B107、SK59、GNS12059和Mo17-476等5个高感红蜘蛛,其中,Mo17-476对红蜘蛛表现为易感。     

玉米抗螨性的大棚人工诱发鉴定与评价分析

利用大棚条件,在人为控制和创造既能满足玉米正常生长发育,又能促使叶螨发生的条件下,进行了玉米抗螨性的鉴定,并以各自交系的受害指数(DMI)和受害面积比率(DMR)为基础采用聚类法和DMR-直观法划分玉米对叶螨的抗感性。结果表明:DMI、DMR和叶螨结网面积比率(SWR)分别为0.06~0.91、1.12%~93.98%和14.10%~99.50%间,其最高值分别是最低值的15.17、83.91和7.06倍;3者间呈极显著正相关(P0.01)。在2种聚类中,参试自交系均分为抗(占52.70%)和感(占47.30%)两大类群及高抗(占27.02%)、抗(占25.68%)、中感(占24.32%)、感(占16.22%)和高感(占6.76%)等5个亚类群;各类群间的DMI和DMR都存在极显著差异(P0.01)。基于DMI和DMR聚类分析划分的类群及亚类群中所包含的自交系种类及其数量都一致,自交系的抗感划分结果相同。与此相比,基于DMR值直观划分玉米对叶螨的抗感性,抗性自交系数量(占78.38%)偏多、抗性偏高。在参试自交系中,BSSSS53-B、9F592、K10-14-1和铁7922的DMI(0.10)、DMR(≤3.00%)和SWR(20.00%)都最小、抗螨性最强,而GNS12059和Mo17-476的DMI(0.75)、DMR(80.00%)和SWR(98.00%)都最大、抗螨性最弱;其中,Mo17-476对玉米叶螨最为敏感。     

Quantitative and qualitative studies on bacterial flora of hybrid tilapia (Oreochromis niloticus × O. aureus) cultured in earthen ponds in Saudi Arabia

The bacterial flora of the rearing pond water and sediment as well as the gills and intestine of healthy hybrid tilapia cultured in Saudi Arabia was estimated quantitatively and qualitatively, the isolates being identified at genus or species level. Total viable counts of bacteria (measured as colony‐forming units, cfu) were in the range 5.6 ± 0.8 × 10³ to 2.4 ± 1.2 × 10⁴ cfu mL^?1 in pond water; 9.3 ± 1.1 × 10⁶ to 1.9 ± 1.5 × 10⁸ cfu g^?1 in sediment; 7.1 ± 0.7 × 10⁵ to 8.7 ± 1.1 × 10⁶ cfu g^?1 in the gills of tilapia; and 3.4 ± 1.8 × 10⁶ to 5.8 ± 0.4 × 10⁷ cfu g^?1 in the intestine of tilapia. In total, 15 bacterial genera and 18 species were identified. Pond water and sediment bacteria reflected the bacterial composition in the gills and intestine of tilapia. In contrast to gill bacteria, more diversification was observed in intestinal bacteria. Corynebacterium urealyticum, Shewanella putrefaciens and Aeromonas hydrophila predominated in all samples. In pond water, C. urealyticurn, S. putrefaciens, A. hydrophila, Flavobacterium sp. and Pseudomonas sp. were the most predominant bacterial species (prevalence > 10%), whereas A. hydrophila, C. urealyticum, S. putrefaciens and Escherichia coli were predominant in pond sediment, and C. urealyticum, S. putrefaciens and A. hydrophila were predominant in both the gills and intestine of tilapia.     

Land cover mapping of deciduous forest regions using ETM+ data: a case study of Azerbaijan Province,Iran

Up to date information about the existing land cover patterns and changes in land cover over time is one of the prime prerequisites for the preparation of an integrated development plan and economic development program of a region. By using ETM+ image data from 2002, we provided a land cover map of deciduous forest regions in Azerbaijan Province, Iran. Initial qualitative evaluation of the data showed no significant radiometric errors. Image classification was carried out using a maximum likelihood-based supervised classification method. In the end, we determined five major land cover classes, i.e., grass lands, deciduous broad-leaf forest, cultivated land, river and land without vegetation cover. Accuracy, estimated by the use of criteria such as overall accuracy from a confusion matrix of classification was 86% with a 0.88 Kappa coefficient. Such high accuracy results demonstrate that the combined use of spectral and textural characteristics increased the number of classes in the field classification, also with excellent accuracy. The availability and use of time series of remote sensing data permit the detection and quantification of land cover changes and improve our understanding of the past and present status of forest ecosystems.     

High prevalence of antibiotic resistance in pathogenic Escherichia coli from large- and small-scale poultry farms in Bangladesh

Antibiotic resistance in avian bacterial pathogens is a common problem in the Bangladesh poultry industry. The aim of the present study was to provide information on the present status of antibiotic resistance patterns in avian pathogenic Escherichia coli in Bangladesh. Of 279 dead or sick poultry of different ages, 101 pathogenic E coli strains isolated from broilers and layer hens with colibacillosis infections were screened to determine phenotypic expression of antimicrobial resistance against 13 antibiotics used in both veterinary and human medicine in Bangladesh. Of 101 pathogenic E. coli isolates, more than 55% were resistant to at least one or more of the tested compounds, and 36.6% of the isolates showed multiple-drug-resistant phenotypes. The most common resistances observed were against tetracycline (45.5%), trimethoprim-sulphamethoxazole (26.7%), nalidixic acid (25.7%), ampicillin (25.7%), and streptomycin (20.8%). Resistance to ciprofloxacin (12.9%), chlormaphenicol (8.9%), nitrofurantoin (2%), and gentamicin (2%) was also observed, and none of the isolates were resistant to tigecycline as well as extended spectrum beta-lactamase (ESBL) producers. One isolate was resistant to cefuroxime (1%), cefadroxil (1%), and mecillinam (1%) but was not an ESBL producer. Resistance rates, although significant in Bangladeshi isolates, were found to be lower than those reported for avian isolates from the Republic of Korea and clinical, avian, and environmental isolates from Bangladesh. The high level of antibiotic resistance in avian pathogens from Bangladesh is worrisome and indicates that widespread use of antibiotics as feed additives for growth promotion and disease prevention could have negative implications for human and animal health and the environment.     

Questionnaire-based survey on the clinical management of canine leishmaniosis in the Madrid region (central Spain)

This paper describes a questionnaire designed to gain information on how veterinarians clinically manage canine leishmaniosis (CanL) in the Madrid region (central Spain). The present survey is one of the several similar questionnaire-based surveys conducted within the framework of the project EDEN (Emerging Diseases in a changing European eNvironment). The questionnaire sought to obtain data regarding the main clinical manifestations observed, the diagnostic methods used and the preventive measures recommended. Its Spanish version was sent by post to veterinary practitioners within the study area in two lots, one sent out in December 2006 and the other in March 2007. Only 174 of the 760 questionnaires sent were completed and returned (reply rate of 23%). Among the completed questionnaires, clinics differed widely in terms of features such as the habitats of the dogs (urban, peri-urban or rural) and patient volumes. Clinics attending dogs from peri-urban/rural habitats reported more suspected (p<0.001), confirmed (p=0.001) and newly diagnosed (p=0.001) cases/year than clinics providing service to a city clientele alone. According to the veterinary practitioners, skin lesions, lymphadenomegaly and weight loss were commonly observed, although these signs are not specific to CanL. Signs described to be of high diagnostic value were epistaxis and kidney disease. All the veterinarians polled reported that a suspicion of Leishmania infantum infection was confirmed by at least a serological method; the immunofluorescence antibody test (IFAT) being the technique most used. To prevent the disease, most vets recommended topical synthetic pyrethroids applied as impregnated collars or spot-ons. It is observed that despite considerable progress is being made in clinical management and controlling the disease, in Madrid Region its incidence continues to increase.