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Development of New Submergence Tolerant Rice Variety for Bangladesh Using Marker-Assisted Backcrossing

Rice science 2015年第1期22卷 16-26页

作者： khandakar md.iftekharuddaula Helal Uddin AHMED Sharmistha GHOSAL Zakiah Rahman MONI Al AMIN md Shamsher ALI Plant Breeding Division Bangladesh Rice Research Institute

Submergence tolerant high yielding rice variety was developed using BR11 as a recipient parent applying foreground, phenotypic and background selection approaches. Recombinant selection was found essential to minimize linkage drag by BC2F2 generation. Without recombinant selection, the introgression size in the backcross recombinant lines （BRLs） was approximately 15 Mb on the carrier chromosome. The BRLs were found submergence tolerance compared to the check varieties under complete submergence for two weeks at Bangladesh Rice Research Institute, and produced higher yield compared to the isogenic Subl-line under controlled submerged condition. The BRL IR85260-66-654-Gaz2 was released as BRRI dhan52 in 2010, which was the first high yielding submergence tolerant variety in Bangladesh. BRRI dhan52 produced grain yield ranging from 4.2 to 5.2 t/hm2 under different flash flood prone areas of Bangladesh in three consecutive seasons. The study demonstrated the efficiency of recombinant selection and better adaptability of the newly released submergence tolerant high yielding variety in flash flood prone different areas of the country with respect to submergence tolerance and yield potential.

关键词： backcross recombinant line marker-assisted backcrossing recombinant selection rice submergence tolerance

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Morphological and Genetical Variability among Rhizoctonia solani Isolates Causing Sheath Blight Disease of Rice

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Rice science 2016年第1期23卷 42-50页

作者： Zakiah Rahman MONI md Ansar ALI md Shahidul ALAM md Asif RAHMAN md Rejwan BHUIYAN md Salim MIAN khandakar md.iftekharuddaula md Abdul LATIF Mohammad Ashik Iqbal KHAN Plant Breeding Division Bangladesh Rice Research Institute Director Research Bangladesh Rice Research Institute Department of Botany Rajshahi University Department of Genetics and Plant Breeding Bangabandhu Sheikh Mujibur Rahman Agricultural University Plant Pathology Division Bangladesh Rice Research Institute

Eighteen isolates of Rhizoctonia solani collected from infected rice plants in four different locations of Bangladesh were studied by using morphological characters and molecular markers. Anastomosis study with a reference isolate confirmed that all the isolates belonged to R. solani. Significant variation was observed in sclerotial size, shape and distribution. Un-weighted pair group method with arithmetic mean dendrogram constructed based on the Gower＇s general similarity coefficient showed that these isolates were grouped into four clusters at the 0.68 similarity coefficent according to morphological characters. Cluster I was a major cluster consisting of 13 isolates, while clusters Ⅱ to Ⅳ consisted of 1 or 2 isolates. Analyses by variable number of tandem repeat and amplified fragment length polymorphism markers showed that the isolates were grouped into five and three clusters at a similarity coefficient of 0.64 and 0.69, respectively. Although most of the variability was found between isolates from different regions as expected, significant variation was observed within the isolates collected from similar agro-ecological regions. Our results suggest the presence of different races of R. solani within the same local geographic regions.

关键词： rice Rhizoctonia solani fungal variability molecular marker morphological character

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Impact of Nitrogen, Phosphorus and Potassium on Brown Planthopper and Tolerance of Its Host Rice Plants

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Rice science 2016年第3期23卷 119-131页

作者： md Mamunur RASHID Mahbuba JAHAN khandakar Shariful ISLAM Plant Physiology Division Bangladesh Rice Research Institute Department of Entomology Bangladesh Agricultural University

The brown planthopper(BPH),Nilaparvata lugens(St?l),appeared as a devastating pest of rice in Asia. Experiments were conducted to study the effects of three nutrients,nitrogen(N),phosphorus(P) and potassium(K),on BPH and its host rice plants. Biochemical constituents of BPH and rice plants with varying nutrient levels at different growth stages,and changes in relative water content(RWC) of rice plants were determined in the laboratory. Feeding of BPH and the tolerance of rice plants to BPH with different nutrient levels were determined in the nethouse. Concentrations of N and P were found much higher in the BPH body than in its host rice plants,and this elemental mismatch is an inherent constraint on meeting nutritional requirements of BPH. Nitrogen was found as a more limiting element for BPH than other nutrients in rice plants. Application of N fertilizers to the rice plants increased the N concentrations both in rice plants and BPH while application of P and K fertilizers increased their concentrations in plant tissues only but not in BPH. Nitrogen application also increased the level of soluble proteins and decreased silicon content in rice plants,which resulted in increased feeding of BPH with sharp reduction of RWC in rice plants ultimately caused susceptible to the pest. P fertilization increased the concentration of P in rice plant tissues but not changed N,K,Si,free sugar and soluble protein contents,which indicated little importance of P to the feeding of BPH and tolerance of plant against BPH. K fertilization increased K content but reduced N,Si,free sugar and soluble protein contents in the plant tissues which resulted in the minimum reduction of RWC in rice plants after BPH feeding,thereby contributed to higher tolerance of rice plants to brown planthopper.

关键词： Nilaparvata lugens relative water content host tolerance nitrogen phosphorus potassium rice nutrient subsidy

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Flexural Strength and Load-Deflection Behaviour of Hybrid Thermoset Composites of Wood and Canola Biopolymers

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Advanced Fiber Materials 2021年第5期3卷 331-346页

作者： Ikra Iftekhar Shuvo md.Saiful Hoque md.Shadhin Lovely K.M.khandakar University of Alberta EdmontonCanada University of Manitoba WinnipegCanada

The study aims to incorporate cellulosic canola(Brassica napus L.)biopolymers with wood biomass to increase flexural strength more than wood fraction alone.A facile fabrication process-at ambient temperature-is employed for ease of producing two different sets of bio-composites utilizing unsaturated polyester resin:pristine composite structures of 100%wood and hybrid composite structures of a canola-wood *** curing process is accompanied by methyl ethyl ketone peroxide(MEKP).Besides the lightweight feature,the hybrid composite structures exhibit maximum flexural strength up to 59.6 and 89.58 MPa at 2.5 and 5%fibre polymer fraction,outperforming the pristine wood composites(49.25 MPa).Also,the bending behaviours of the composite structures are illustrated by the load-deflection curves and the associated SEM micrographs display their fractured and debonded surface at the *** novel canola fibre benefits from its inherent hollow architecture,facilitating an excellent strength to weight ratio for the thermoset ***,canola displays a fibre diameter and density of 79.80(±41.31)μm and 1.34(±0.0014)g/cc,contributing effectively towards the flexure performance and high packing *** breaking tenacity(13.31±4.59 g-force/tex)and tensile strength(174.93±60.29)of canola fibres are comparable to other bast *** synergy among fibre diameters,density and break-ing tenacity creates a good interphase to successfully transfer the external compressive load from the resin matrix to the ***,the two-parameter Weibull distribution model is applied for predicting the failure and reliability probability of composite specimens against a wide range of compressive ***,prioritized SWOT factors have been summa-rized associated with the prospects and key challenges of canola biopolymers-an attempt to strategize the planning and decision-making process for a potential business *** introduction of canola into the pla

关键词： Flexural strength Load-deflection Fibre Composite Weibull distribution

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Ecological fitness of brown planthopper, Nilaparvata lugens (Stål), to rice nutrient management

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Ecological Processes 2017年第1期6卷 149-158页

作者： md.Mamunur Rashid Mahbuba Jahan khandakar S.Islam md.Abdul Latif Plant Physiology Division Bangladesh Rice Research Institute(BRRI)Gazipur 1701Bangladesh Department of Entomology Bangladesh Agricultural UniversityMymensingh 2202Bangladesh Plant Pathology Division Bangladesh Rice Research Institute(BRRI)Gazipur 1701Bangladesh

Introduction:The brown planthopper(BPH),Nilaparvata lugens(Stål)(Hemiptera:Delphacidae),is a notorious insect pest of *** supplementation can alter plant biochemical compositions which may indirectly affect on ecological fitness parameters of its insect ***,few findings are available on nutrient-induced ecological fitness of BPH and relationship of BPH fitness parameters with its host rice plant biochemical ***:We studied the main and interaction effects of nitrogen(N),phosphorus(P),and potassium(K)inputs on BPH fitness,as measured by the following variables:nymph survival,nymphal duration,adult body weight,and its *** planthopper fitness parameters were regressed as function of rice plant(Oryza sativa)biochemical composition.A completely randomized design with four replications in a factorial scheme was used considering N,P,and K levels as ***:Nitrogen application to the host rice plants provided greater survival and enhanced body weight of *** nymphal duration was found to decrease with N subsidy that caused shorter generation time of *** compounds N and soluble protein(SP),total free sugar(TFS),and silicon(Si)content in rice plant tissue correlated strongly with all fitness traits of ***,SP,and TFS associated positively with BPH survival and body weight,while negatively with nymphal *** contrast,Si had negative correlation with BPH survival and body weight,but positive with nymphal *** supplementation to host plant contributed to increase BPH body *** of P with all parameters of BPH were weak except body weight which was highly significant and *** between N and P inputs demonstrated significant effect on BPH body *** of K had no significant effect on BPH survival and *** analysis did not detect significant relationship of BPH fitness parameters with plant tissue content of ***:The res

关键词： Nilaparvata lugens Nutrient management Survival Nymphal duration Body weight

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Recognition of Bangla Handwritten Number Using Combination of PCA and FIS with the Aid of DWT

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Journal of Computer and Communications 2020年第9期8卷 109-125页

作者： Samsunnahar khandakar md. Imdadul Islam Fahima Tabassum Risala T. Khan Department of Computer Science & Engineering Jahangirnagar University Dhaka Bangladesh Institute of Information Technology Jahangirnagar University Dhaka Bangladesh

The structure of any Bangla numerical character is more complex compared to English numerical character. Two pairs of numerical character in Bangla resembles to be closed and they are: “one and nine” and “five and six”. We found that, handwritten Bangla numerical character cannot be recognized using single machine learning algorithm or discrete wavelet transform (DWT). Above phenomenon motivated us to use combination of DWT, Fuzzy Inference System (FIS) and Principal Component Analysis (PCA) to recognize numerical characters of Bangla in handwritten format. The four lowest spectral components of a preprocessed image are taken using DWT, which is considered as the feature vector to recognize the digits in first phase. The feature vector is then applied to FIS and PCA separately. The combined method provides recognition accuracy of 95.8% whereas application of individual method gives less rate of accuracy. Instead of storing the images itself in a folder, if we can store the feature vector of images achieved from DWT in tabular form. The records of table can be applied in FIS, PCA or other object detection algorithm. Although the technique used in the paper can detect objects with moderate rate of accuracy but can save huge storage against a benchmark database of images. If a tradeoff is made between storage requirements and accuracy of recognition, the model of the paper is preferable compared to other present state-of-art. Another finding of the paper is that, the spectral components of images acquired by DWT only matched with FIS and PCA for classification but do not match properly with unsupervised (K-mean clustering) and supervised (support vector machine) learning.

关键词： Spectral Components Recognition Accuracy De-Noising Thinning Scheme Principal Components

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Focused Web Crawling: A Framework for Crawling of Country Based Financial Data

Focused Web Crawling: A Framework for Crawling of Country Ba...

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2010 2nd IEEE International Conference on Information and Financial Engineering(ICIFE2010)

作者： Manas Kanti Dey Hasan md Suhag Chowdhury Debakar Shamanta khandakar Entenam Unayes Ahmed Department of Computer Science ＆ Engineering Shahjalal University of Science and Technology Sylhet Bangladesh

Crawling the Web quickly and entirely is an expensive, unrealistic goal because of the required enormous amounts of hardware and network resources. But when only information about a predefined topic set is desired, a specialization of the aforementioned process called "focused crawling" is used. A focused crawler is an agent that targets a particular topic and visits and gathers only a relevant, narrow Web segment while trying not to waste resources on irrelevant material. Compared to the standard web search engines, focused crawlers yield good recall as well as good precision by restricting themselves to a limited domain. In this paper we will introduce the technique of focused crawling of country based financial data.

关键词： Crawler Focused Crawler Information retrieval Financial data

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