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Pt-Ga和Ga-Mo双金属催化剂的丙烷脱氢反应性能研究 被引量:3
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作者 王凯琪 muhammad zeeshan +4 位作者 韩金明 胡平 朱贻安 隋志军 周兴贵 《天然气化工—C1化学与化工》 CAS CSCD 北大核心 2020年第2期5-10,共6页
Pt金属催化剂的高成本和结焦失活是制约其在丙烷脱氢(PDH)工艺中应用的重要因素。因此,对Pt催化剂进行改性以及开发廉价的非贵金属催化剂是目前PDH的主流研究方向。本文对Pt/γ-Al2O3催化剂以添加助剂的手段进行性能优化,借助H2-TPR、TG... Pt金属催化剂的高成本和结焦失活是制约其在丙烷脱氢(PDH)工艺中应用的重要因素。因此,对Pt催化剂进行改性以及开发廉价的非贵金属催化剂是目前PDH的主流研究方向。本文对Pt/γ-Al2O3催化剂以添加助剂的手段进行性能优化,借助H2-TPR、TG、Raman、TEM等表征技术进行研究,发现Pt-Ga催化剂较Pt-Sn催化剂具有更好的催化性能,表明适量引入Ga元素能够与Pt发生很好的协同作用。此外,制备了Ga-Mo非贵金属催化剂,降低了催化剂失活的速率,获得了良好的脱氢性能。 展开更多
关键词 丙烷脱氢 丙烯 Pt-Ga Ga-Mo 双金属催化剂 协同作用 结焦
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Influence of Seedling Age and Nitrogen Rates on Productivity of Rice (<i>Oryza sativa</i>L.): A Review 被引量:7
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作者 muhammad Mahran Aslam muhammad zeeshan +5 位作者 Ayesha Irum muhammad Umair Hassan Saif Ali Rashid Hussain Pia muhammad Adnan Ramzani muhammad Farhan Rashid 《American Journal of Plant Sciences》 2015年第9期1361-1369,共9页
Rice is an important crop and the food security of the world is strongly associated with it as it is the staple food of half of the world’s population. Among various agro-management practices seedling age and nitroge... Rice is an important crop and the food security of the world is strongly associated with it as it is the staple food of half of the world’s population. Among various agro-management practices seedling age and nitrogen rates significantly affected its growth, development and yield components. Rice cultivars performed differently when transplanted in field at varying seedling ages depending upon their genetic makeup and adoptability to certain environmental conditions. Seedling age plays an important role in yield contributing parameters like number of productive tillers, panicle length, filled grains panicle-1 and 1000-kernel weight leading to higher paddy yield in different rice cultivars and hybrids. Nitrogen is required in huge quantity in rice production as it is an important constituent of plant parts and processes. Paddy yield increases significantly with the increase in nitrogen rate but after a certain limit yield starts decreasing. Keeping in view the significance of seedling age and nitrogen rates in different rice cultivars and hybrids, an effort has been made to review some research work already conducted and will be helpful to the researchers and scientists to plan future strategies. 展开更多
关键词 Hybrid RICE SEEDLING Age Nitrogen Rates PADDY Yield
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Outcomes after stenting for malignant large bowel obstruction without radiologist support 被引量:1
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作者 Rao Khalid Mehmood Jody Parker +5 位作者 Patricia Kirkbride Shakil Ahmed Fayyaz Akbar Eays Qasem muhammad zeeshan Ernest Jehangir 《World Journal of Gastroenterology》 SCIE CAS 2014年第20期6309-6313,共5页
AIM: To assess outcomes after colonic stent insertion for obstructing colorectal malignancies performed by an endoscopist without radiologist support.
关键词 Self-expanding colonic stents Colorectal cancer PALLIATION Interventional radiology ENDOSCOPY
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Assessment of Rock Mass Quality and Deformation Modulus by Empirical Methods along Kandiah River, KPK, Pakistan 被引量:1
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作者 Mian Sohail Akram Kamran Mirza +1 位作者 muhammad zeeshan muhammad Asad Jabbar 《Open Journal of Geology》 2018年第10期947-964,共18页
The pivotal aim of this study is to evaluate the rock mass characterization and deformation modulus. It is vital for rock mass classification to investigate important parameters of discontinuities. Therefore, Rock Mas... The pivotal aim of this study is to evaluate the rock mass characterization and deformation modulus. It is vital for rock mass classification to investigate important parameters of discontinuities. Therefore, Rock Mass Rating (RMR) and Tunneling quality index (Q) classification systems are applied to analyze 22 segments along proposed tunnel routes for hydropower in Kandiah valley, Khyber Pakhtunkhwa, Pakistan. RMR revealed the range of fair to good quality rocks, whereas Q yielded poor to fair quality rocks for investigated segments of the rock mass. Besides, Em values were acquired by empirical equations and computer-aided program RocLab, and both methods presented almost similar variation trend of their results. Hence, the correlations of Em with Q and RMR were carried out with higher values of the regression coefficient. This study has scientific significance to initially understand the rock mass conditions of Kandiah valley. 展开更多
关键词 ROCK Mass Classification RMR and Q Deformation MODULUS (Em) Empirical EQUATIONS RocLab TUNNEL
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Geotechnical Investigation and Prediction of Rock Burst, Squeezing with Remediation Design by Numerical Analyses along Headrace Tunnel in Swat Valley, Khyber Pakhtunkhwa, Pakistan 被引量:1
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作者 Mian Sohail Akram Kamran Mirza +2 位作者 muhammad zeeshan muhammad Ali Luqman Ahmed 《Open Journal of Geology》 2018年第10期965-986,共22页
This study illustrates the classification of the rock mass and evaluation of rock squeezing, rock burst potential, deformation modulus along the proposed tunnel alignment of small hydropower in Swat Valley, Khyber Pak... This study illustrates the classification of the rock mass and evaluation of rock squeezing, rock burst potential, deformation modulus along the proposed tunnel alignment of small hydropower in Swat Valley, Khyber Pakhtunkhwa (KP), Pakistan. The field and laboratory studies were conducted to classify the rock mass by using geomechanical classification systems i.e. Rock Mass Rating (RMR), tunneling quality index (Q), Rock Mass Index (RMi). The empirical relations classified the ground as non-squeezing and minor to non-squeezing conditions, respectively. Whereas, other methods depict minor to medium bursting potential along chainage 1+000 to 4+000 m, while results along chainage 2+400 - 2+800 m present medium to high bursting potential. Furthermore, numerical analyses were carried out by RS3 for elastic and plastic conditions in order to assess the total displacement of each section in unsupported and supported conditions. The results gave maximum displacement along chainage 2+400 - 2+800 m (19.2 mm in unsupported and 16mm in supported condition) and minimum displacement along chainage 0+876 - 1+000 m (1.4 mm in unsupported and 1.3 mm in supported condition). Hence, the estimated support by empirical methods has been optimized by using numerical analyses for the stability of rock mass along the tunnel. 展开更多
关键词 TUNNEL ROCK SQUEEZING ROCK BURST ROCK Mass Characterization Numerical Analyses
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Block-Wise Neural Network for Brain Tumor Identification in Magnetic Resonance Images
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作者 Abdullah A.Asiri muhammad Aamir +7 位作者 Ahmad Shaf Tariq Ali muhammad zeeshan muhammad Irfan Khalaf A.Alshamrani Hassan A.Alshamrani Fawaz F.Alqahtani Ali H.D.Alshehri 《Computers, Materials & Continua》 SCIE EI 2022年第12期5735-5753,共19页
The precise brain tumor diagnosis is critical and shows a vital role in the medical support for treating tumor patients.Manual brain tumor segmentation for cancer analysis from many Magnetic Resonance Images(MRIs)crea... The precise brain tumor diagnosis is critical and shows a vital role in the medical support for treating tumor patients.Manual brain tumor segmentation for cancer analysis from many Magnetic Resonance Images(MRIs)created in medical practice is a problematic and timewasting task for experts.As a result,there is a critical necessity for more accurate computeraided methods for early tumor detection.To remove this gap,we enhanced the computational power of a computer-aided system by proposing a finetuned Block-Wise Visual Geometry Group19(BW-VGG19)architecture.In this method,a pre-trained VGG19 is fine-tuned with CNN architecture in the block-wise mechanism to enhance the system`s accuracy.The publicly accessible Contrast-Enhanced Magnetic Resonance Imaging(CE-MRI)dataset collected from 2005 to 2020 from different hospitals in China has been used in this research.Our proposed method is simple and achieved an accuracy of 0.98%.We compare our technique results with the existing Convolutional Neural network(CNN),VGG16,and VGG19 approaches.The results indicate that our proposed technique outperforms the best results associated with the existing methods. 展开更多
关键词 CNN brain tumor block-wise structure VGG19 VGG16
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R-IDPS: Real Time SDN-Based IDPS System for IoT Security
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作者 Noman Mazhar Rosli Saleh +3 位作者 Reza Zaba muhammad zeeshan M.Muzaffar Hameed Nauman Khan 《Computers, Materials & Continua》 SCIE EI 2022年第11期3099-3118,共20页
The advent of the latest technologies like the Internet of things(IoT)transforms the world from a manual to an automated way of lifestyle.Meanwhile,IoT sector open numerous security challenges.In traditional networks,... The advent of the latest technologies like the Internet of things(IoT)transforms the world from a manual to an automated way of lifestyle.Meanwhile,IoT sector open numerous security challenges.In traditional networks,intrusion detection and prevention systems(IDPS)have been the key player in the market to ensure security.The challenges to the conventional IDPS are implementation cost,computing power,processing delay,and scalability.Further,online machine learning model training has been an issue.All these challenges still question the IoT network security.There has been a lot of research for IoT based detection systems to secure the IoT devices such as centralized and distributed architecture-based detection systems.The centralized system has issues like a single point of failure and load balancing while distributed system design has scalability and heterogeneity hassles.In this study,we design and develop an agent-based hybrid prevention system based on software-defined networking(SDN)technology.The system uses lite weight agents with the ability to scaleup for bigger networks and is feasible for heterogeneous IoT devices.The baseline profile for the IoT devices has been developed by analyzing network flows from all the IoT devices.This profile helps in extracting IoT device features.These features help in the development of our dataset that we use for anomaly detection.For anomaly detection,support vector machine has been used to detect internet control message protocol(ICMP)flood and transmission control protocol synchronize(TCP SYN)flood attacks.The proposed system based on machine learning model is fully capable of online and offline training.Other than detection accuracy,the system can fully mitigate the attacks using the software-defined technology SDN technology.The major goal of the research is to analyze the accuracy of the hybrid agent-based intrusion detection systems as compared to conventional centralized only solutions,especially under the flood attack conditions generated by the distributed denial of service(DDoS)attacks.The system shows 97%to 99%accuracy in simulated results with no false-positive alarm.Also,the system shows notable improvement in terms of resource utilization and performance under attack scenarios. The R-IDPS is scalable, and thesystem is suitable for heterogeneous IoT devices and networks. 展开更多
关键词 Machine learning Internet of things software defined networking distributed denial of service attacks
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Assessment of Rock Mass Quality and Support Estimation along Headrace Tunnel of a Small Hydropower in District Mansehra, Khyber Pakhtunkhwa, Pakistan
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作者 Mian Sohail Akram muhammad zeeshan +1 位作者 muhammad Haroon Kamran Mirza 《Open Journal of Geology》 2019年第11期809-828,共20页
The main purpose of this study is to classify the rock mass quality by using rock mass quality (Q) and Rock Mass Rating (RMR) systems along headrace tunnel of small hydropower in Mansehra District, Khyber Pakhtunkhwa.... The main purpose of this study is to classify the rock mass quality by using rock mass quality (Q) and Rock Mass Rating (RMR) systems along headrace tunnel of small hydropower in Mansehra District, Khyber Pakhtunkhwa. Geological field work was carried out to determine the orientation, spacing, aperture, roughness and alteration of discontinuities of rock mass. The quality of rock mass along the tunnel route is classified as good to very poor quality by Q system, while very good to very poor by RMR classification system. The relatively good rock conditions are acquired via RMR values that are attributed to ground water conditions, joint spacing, RQD and favorable orientation of discontinuities with respect to the tunnel drive. The petrographic studies revealed that study area is mainly comprised of five major geological rock units namely quartz mica schist (QMS), garnet mica schist (GMS), garnet bearing quartz mica schist (G-QMS), calcareous schist (CS), marble (M). The collected samples of quartz mica schist, marble and garnet bearing quartz mica schist are fine to medium grained, compact and are cross cut by few discontinuities having greater spacing. Therefore, these rocks have greater average RQD, Q values, RMR ratings as compared to garnet mica schist and calcareous schist. 展开更多
关键词 TUNNEL PETROGRAPHY Rock Mass Rating (RMR) Tunneling Quality Index (Q System) SUPPORT ESTIMATION
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Geotechnical and Hydrological Characterization of Subsurface for Metallic Minerals Mining Operations in Punjab, Pakistan
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作者 Mian Sohail Akram Kamran Mirza +1 位作者 Usman Ali muhammad zeeshan 《Open Journal of Geology》 2019年第11期752-767,共16页
The study area is covered by alluvium having average thickness of about 200 m that is underlain by the Precambrian basement rock units including iron ore to be mined in future. In this regards, necessary campaign of s... The study area is covered by alluvium having average thickness of about 200 m that is underlain by the Precambrian basement rock units including iron ore to be mined in future. In this regards, necessary campaign of subsurface investigations including both geotechnical and hydrogeological has been carried. In geotechnical investigations, disturbed and undisturbed samples were collected from five (5) boreholes and hydrological investigations by using water pump out test were conducted to determine the characteristics of aquifer. Rock samples were also collected from already drilled boreholes for iron ore estimation from a depth of more than 200 m. The laboratory testing has classified alluvium as silty sand/sandy silt (SP-SM/SM) and clayey silt/non-plastic silt (CL-ML/ML) as per soil classification criteria having angel of friction of 31.4 - 38.5 degree with bulk density of 1.461 - 1.853 g/cc. The initial void ratio (eo) varies from 0.412 to 0.952 with no swell potential in consolidation tests. The chemical analyses of the soil have indicated values of 0.003% - 0.006%, 0.0012% - 0.0057%, 0.013% - 0.030% sulphate, chloride and organic matter contents respectively with pH-value of 6.92 - 7.56. The strength of the underlying rock was found to be medium strong to very strong corresponding to values of 25 - 140 MPa in uniaxial compression and indirect tensile strength of 15.66 MPa. Hydrological study reveals that aquifer is unconfined and generally isotropic in nature. The average transmissivity, hydraulic conductivity and storage coefficient are 6038 m2/day, 4.0 × 101 m/day and 0.016, respectively that presented aquifer is quite permeable. The cone of influence covered area of 65 m from main production well. For the open pit mining operation, stability analysis is performed by assuming a 4V:1H slope in the bedrock while 1V:1H in the overlying sediments cover using Limit-Equilibrium (LE) analysis in Slide computer program. However, overburden slope was concluded to be unstable with the analyzed slope angle. The deformation analysis for mine slopes by finite element method was performed using Phase 2 (RS) software. The results show maximum deformation is likely to be in order of as high as 700 mm for individual slope riser whereas in the range of 300 to 400 mm for the overall slope. 展开更多
关键词 SUBSURFACE Investigation Rock and Soil SAMPLES Laboratory Tests SLOPE Analyses
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Seasonal variations in dissolved organic matter concentration and composition in an outdoor system for bank filtration simulation 被引量:1
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作者 muhammad zeeshan Omamah Ali +1 位作者 Shamas Tabraiz Aki Sebastian Ruhl 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2024年第1期252-261,共10页
Dissolved organic matter(DOM)in surface waters can vary markedly in character depending on seasonal variations such as rainfall intensity,UV radiations and temperature.Changes in DOM as well as temperature and rainfal... Dissolved organic matter(DOM)in surface waters can vary markedly in character depending on seasonal variations such as rainfall intensity,UV radiations and temperature.Changes in DOM as well as temperature and rainfall intensity over the year can affect the biochemical processes occurring in bank filtration(BF).Identification and characterization of DOM in the surface water could help to optimize the water treatment and provide stable and safe drinking water.This study investigated year-long variations of DOM concentrations and compositions in a surface water of a circulated outdoor pond(research facility)connected to a BF passage.DOM was dominated by humic substances and a changing pattern of DOM in surface water was observed throughout the year.A significant increase of DOM(~38%)in surface water was noted in August compared to November.The fluorescent DOM showed that DOM in summer was enriched with the degradable fraction whilst non-degradable fraction was dominated in winter.A constant(1.7±0.1 mg/L)effluent DOM was recirculated in the system throughout the year.DOM removal through BF varied between 4%to 39%and was achieved within a few meters after infiltration and significantly correlated with influent DOM concentration(R^(2)=0.82,p<0.05).However,no significant(p>0.05)change in the removal of DOM was observed in two subsurface layers(upper and lower).This study highlights the presence of a constant non-degradable DOM in the bank filtrate,which was not affected by temperature,redox conditions and UV radiations. 展开更多
关键词 Bank filtration Dissolved organic matter Dissolved oxygen Fluorescence spectroscopy Excitation-emission matrix
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Effects of spray adjuvants and operation modes on droplet deposition and elm aphid control using an unmanned aerial vehicle
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作者 Zechen Dou Zhihao Fang +3 位作者 Xiaoqiang Han muhammad zeeshan Yapeng Liu Yubin Lan 《International Journal of Agricultural and Biological Engineering》 SCIE 2023年第2期1-9,共9页
A conventional spraying mode and a fully autonomous fruit tree operation mode using a model DJ T30 unmanned aerial vehicle(UAV)were used to control aphids control on elm trees and to clarify the distribution of drople... A conventional spraying mode and a fully autonomous fruit tree operation mode using a model DJ T30 unmanned aerial vehicle(UAV)were used to control aphids control on elm trees and to clarify the distribution of droplets in elm trees sprayed by a UAV.The effects of six aviation spray adjuvants on elm canopy droplet deposition and aphid control were evaluated.ImageJ software was used to analyze and measure the droplet density and deposition of water sensitive paper in two modes;this was done to calculate the droplet uniformity,depositional penetration,and droplet penetration,and to verify the aphid control effect.The results showed that the droplet density increased by 79.7%-100.7% in the upper canopy and 0-394.1%in the lower canopy without adjuvants in the fully autonomous fruit tree operation mode.The upper canopy deposits increased by 65.7%-179.3%,and the lower canopy increased by 0-152.8%.When adjuvants were added,the droplet density in the upper canopy increased by 49.7-56.1%using Jiexiaofeng(JXF),and the lower canopy increased by 138.2%-177.8% using JXF,45.8%-141.3%using Beidatong(BDT),45.5%-92.9% using Gongbei(GB),0-93.5% using Maisi(MS),and 0-95.2%using Manniu(MN).The deposits of the upper canopy increased by 888.1-1154.2% using JXF,0-1298.3% using MN,0-343.9%using BDT,0-422.5% using GB,0-580.3% using MS.The lower canopy increased by 746.4%-1426.0%using JXF,226.2%-231.0% using BDT,435.8%-644.0% using GB,255.0%-322.4%using MS,and 249.3%-360.0%using MN.When JXF was added,the droplet uniformity,droplet penetration and depositional penetration were better than when using other adjuvants.The effects of JXF,BDT and GB in controlling aphids was significantly better than other adjuvants(p<0.05).The following control effects were observed;94.1% with JXF,93.1% with BDT,and 93.3% with GB after 3 d of application,and 97.9% with JXF,95.6% with BDT,and 97.1% with GB after 7 d of application.At the same time,the application of the fully autonomous fruit tree operation mode and JXF can effectively improve the density and deposits,which will produce a superposition optimization effect.Our study focuses on the prevention and control of elm aphid infestations based on the operation mode of a UAV and aviation spray adjuvants,which can provide a baseline for the control of diseases and insect pests using UAVs in agriculture and forestry. 展开更多
关键词 ADJUVANTS UAV operation mode droplet deposition APHID
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Effects of Oxygen Vacancy and Pt Doping on the Catalytic Performance of CeO_(2) in Propane Dehydrogenation:A First-Principles Study 被引量:2
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作者 muhammad zeeshan Qing-Yu Chang +5 位作者 Jun Zhang Ping Hu Zhi-Jun Sui Xing-Gui Zhou De Chen Yi-An Zhu 《Chinese Journal of Chemistry》 SCIE CAS CSCD 2021年第9期2391-2402,共12页
The catalytic properties of the CeO_(2) catalyst for propane dehydrogenation(PDH)are examined by employing the density functional theory calculations.Surface modifications and their effects on the surface reactivity a... The catalytic properties of the CeO_(2) catalyst for propane dehydrogenation(PDH)are examined by employing the density functional theory calculations.Surface modifications and their effects on the surface reactivity are explored by creating the oxygen vacancy and single Pt atom doping.A comparative study between the binding energies of the different PDH reaction species reveals a considerable Lewis acid-base interaction over the pristine and defective surfaces,which dominantly strengthens the bond formation between the adsorbates and the catalyst surface,resulting in the enhancement of surface reactivity.The creation of oxygen vacancy and doping the CeO_(2)(111)surface with single Ptatoms changes the charge distribution over the surface on account of excess 4f electrons.This electronic change in creases the bond formation abilities of the in active Ceatom and hence increases the adsorption stre ngth.Oxygen vacancy in the defective CeO_(2)(111)surface migrates over the surface with the addition of an appropriate adsorbate.Moreover,it is revealed that the propylene is more strongly adsorbed on the single-Pt-atom-doped CeO_(2)(111)surface than the pristine and defective surfaces,which decreases the deep dehydrogenation energy barrier and ultimately results in the lowering of the selectivity. 展开更多
关键词 DEHYDROGENATION ADSORPTION DOPING Heterogeneous catalysis Ab initio calculations
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Breeding for pre-harvest sprouting resistance in bread wheat under rainfed conditions 被引量:1
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作者 muhammad zeeshan Waheed ARSHAD +6 位作者 muhammad Imran KHAN Shiraz ALI Ali NAWAZ Amina BATOOL muhammad TARIQ muhammad Imran AKRAM muhammad Amjad ALI 《Frontiers of Agricultural Science and Engineering》 2018年第2期253-261,共9页
Pre-harvest sprouting in wheat is the germination of seeds within the spikes when rains occur after or during grain ripening, which occurs commonly in the barani tract of Pakistan. Therefore, 10 cultivars and five adv... Pre-harvest sprouting in wheat is the germination of seeds within the spikes when rains occur after or during grain ripening, which occurs commonly in the barani tract of Pakistan. Therefore, 10 cultivars and five advanced lines of spring bread wheat were evaluated for pre-harvest sprouting resistance. After natural rainfall,seeds were immediately collected from the wet spikes and tested for germinating ability. Three different germination tests were applied to hand-threshed seed:(1) spikes threshed on the day of sampling and germination tested immediately,(2) spikes threshed on the day of sampling and germination tested 1 week later, and(3) spikes threshed 1 week after sampling and germination test immediately after threshing. Seeds and spikes kept for 1 week were place on blotting paper at room temperature.Cultivars BARS-09, 09 FJ17, Doukkala-12, NARC-09 and Ouassou-20 exhibited higher sprouting resistance while other genotypes were susceptible to pre-harvest sprouting in each of the three tests. A diallel crossing was conducted with six susceptible and two resistant genotypes to assess the genetic behavior of pre-harvest sprouting resistance.The combining ability(CA) demonstrated a higher proportion of additive genetic effects for sprouting resistance, because of higher variance of general and specific CA for both parameters under study. Doukkala-12 and BARS-09 showed increased pre-harvest sprouting resistance in their F1 descendants. 展开更多
关键词 bread wheat germination index general combining ability pre-harvest sprouting specific combining ability
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