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玉米矮花叶病种子传播与病害发生初步研究 被引量:1
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作者 周益军 程兆榜 +2 位作者 范永坚 章履孝 刘荆 《中国农业大学学报》 CAS CSCD 北大核心 1998年第S1期123-123,共1页
玉米矮花叶病(Maize Dwarf Mosaic Virus,MDMV)是世界上分布广泛、为害严重的玉米病毒病之一。自然情况下可由禾缢管蚜、麦二叉蚜、玉米蚜等20余种蚜虫以非持久性方式传播,有较广泛的禾本科寄主。近年来该病害在江苏及其他地区不断爆发... 玉米矮花叶病(Maize Dwarf Mosaic Virus,MDMV)是世界上分布广泛、为害严重的玉米病毒病之一。自然情况下可由禾缢管蚜、麦二叉蚜、玉米蚜等20余种蚜虫以非持久性方式传播,有较广泛的禾本科寄主。近年来该病害在江苏及其他地区不断爆发流行,给玉米生产造成了严重危害。导致病害流行的重要因素之一是目前生产上大面积种植的品种多数为感病品种,种子带毒和传播问题长期以来一直未受到足够的重视。1997年~1998年作者对江苏玉米生产上使用的品种以及部分种质资源。 展开更多
关键词 玉米矮花叶病 病害发生 种传率 玉米生产 初步研究 子带毒 爆发流行 感病品 玉米病毒病 严重危害
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大豆花叶病毒种子带毒及其检测技术研究 被引量:2
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作者 梅丽艳 《黑龙江农业科学》 1997年第3期17-19,共3页
采用生长试验、Top-crop枯斑反应、免疫电镜、A-蛋白包被微板酶联免疫法等4种方法对大豆不同品种种子带毒率进行检测,结果表明,4种检测方法结果基本吻合。检测种子带毒部位试验结果表明,大豆种子的胚部和子叶都带有病毒... 采用生长试验、Top-crop枯斑反应、免疫电镜、A-蛋白包被微板酶联免疫法等4种方法对大豆不同品种种子带毒率进行检测,结果表明,4种检测方法结果基本吻合。检测种子带毒部位试验结果表明,大豆种子的胚部和子叶都带有病毒。同品种内种传率与种皮斑驳程度无明显关系,而不同大豆品种种传率表现明显差异。 展开更多
关键词 大豆花叶病毒 种传率 免疫 检测
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Genetic Effects and Heterosis in Plant Height and Internode Traits of Japonica-Indica Hybrid Rice 被引量:2
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作者 林建荣 宋昕蔚 吴明国 《Agricultural Science & Technology》 CAS 2012年第4期746-750,共5页
[Objective] This study aimed to investigate the genetic effects and heterosis of plant height and internode traits of japonica-indica hybrid rice. [Methed] Incomplete diallel crosses were made between six japonica CMS... [Objective] This study aimed to investigate the genetic effects and heterosis of plant height and internode traits of japonica-indica hybrid rice. [Methed] Incomplete diallel crosses were made between six japonica CMS lines and nine indica widecompatibility restorer lines; the genetic effects of plant height and internode traits of japonica-indica hybrid rice were analyzed using the additive-dominance genetic model. [Result] The ple, nt height, panicle length and the length of internode 1 of japonica-in- dica hybrid rice were mainly controlled by the additive effects; but the length of in- ternode 3, internode 4 and internode 5 were mainly controlled by dominance effects. Both the narrow sense heritability and broad sense heritability of plant height, panicle length, number of elongated internodes and length of most internodes reached signifi- cance level. The positive phenotypic correlation, genetic correlation, additive correla- tion and dominance correlation between plant height and panicle length, number of e- longated internodes and internode length were significant; and most of the other paired traits were significantly positively correlated. Heterosis analysis showed that the positive heterosis value over mid-parent and positive heterosis value over better- parent of the length of internode 3, internode 4, internode 5 and internode 6 reached significant level, and the heterosis value over mid-parent of plant height reached extreme significance level. [Conclusion] This study will provide reliable theoretical basis for the genetic improvement and heterosis utilization of plant height and internode traits in japonica-indica hybrid rice. 展开更多
关键词 Japonica-indica hybrid rice Plant height Internode traits Genetic effects HERITABILITY Correlation HETEROSIS
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番茄溃疡病及其防治
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作者 务农 《农村科技》 1995年第5期9-9,共1页
番茄溃疡病是一种由细菌引起的维管束病害。病株从幼苗到座果期都可发生萎蔫和死亡。病害发展后期茎叶上出现狭长的条斑,上下扩展,髓部变褐变空,病部增粗,茎秆上产生大量气生根。病原细菌通过维管束侵染果实、胎座和果肉,在暴风雨多或... 番茄溃疡病是一种由细菌引起的维管束病害。病株从幼苗到座果期都可发生萎蔫和死亡。病害发展后期茎叶上出现狭长的条斑,上下扩展,髓部变褐变空,病部增粗,茎秆上产生大量气生根。病原细菌通过维管束侵染果实、胎座和果肉,在暴风雨多或有喷灌条件的地方,果实上常出现"鸟眼斑",即中心有褐色不规则形小点,外围呈白色晕圈,十分明显可辨。病原细菌从伤口入侵,叶片的毛状体也是侵染的通道,可借整枝、打权或中耕伤根而蔓延,除侵染番茄外,还可侵染一些茄科植物。种子内外均可带菌,一般种传率为1%-5%,但从病果上采收的种子种传率高达53%。种子带菌是此病远距离传播扩散的重要途径。防治方法:1.加强植物检疫。禁止非病区到病区调种。 展开更多
关键词 病原细菌 维管束 番茄 种传率 侵染 病害发展 植物检疫 防治方法 溃疡病 非病区
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A delayed SEIRS epidemic model with impulsive vaccination and nonlinear incidence rate
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作者 Jiancheng Zhang and Jitao Sun 《International Journal of Biomathematics》 2014年第3期149-162,共14页
In this paper, a delayed SEIRS epidemic model with nonlinear incidence rate and impul- sive vaccination is investigated. In vaccination strategy, we perform impulsive vaccina- tion of newborn infants. Using the discre... In this paper, a delayed SEIRS epidemic model with nonlinear incidence rate and impul- sive vaccination is investigated. In vaccination strategy, we perform impulsive vaccina- tion of newborn infants. Using the discrete dynamic system determined by stroboscopic map, we obtain an infection-free periodic solution and establish conditions, on which the solution is globally attractive. We also conclude that the disease is permanent if the parameters of the model satisfy appropriate conditions. Finally, we illustrate the effec- tiveness of our theorems with numerical simulation. The results obtained in this paper are a good extension of the results obtained in [J. Hou and Z. Teng, Continuous and impulsive vaccination of SEIR epidemic models with saturation incidence rate, Math. Comput, Simulat. 79 (2009) 3038 3054] to the corresponding delayed SEIRS epidemic model with nonlinear incidence rate and impulsive vaccination. 展开更多
关键词 SEIRS impulsive vaccination DELAY globally attractive permanence.
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A fast face detection architecture for auto-focus in smart-phones and digital cameras 被引量:1
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作者 Peng OUYANG Shouyi YIN +2 位作者 Chenchen DENG Leibo LIU Shaojun WEI 《Science China Earth Sciences》 SCIE EI CAS CSCD 2016年第12期175-187,共13页
Auto-focus is very important for capturing sharp human face centered images in digital and smart phone cameras. With the development of image sensor technology, these cameras support more and more highresolution image... Auto-focus is very important for capturing sharp human face centered images in digital and smart phone cameras. With the development of image sensor technology, these cameras support more and more highresolution images to be processed. Currently it is difficult to support fast auto-focus at low power consumption on high-resolution images. This work proposes an efficient architecture for an Ada Boost-based face-priority auto-focus. The architecture supports block-based integral image computation to improve the processing speed on high-resolution images; meanwhile, it is reconfigurable so that it enables the sub-window adaptive cascade classification, which greatly improves the processing speed and reduces power consumption. Experimental results show that 96% detection rate in average and 58 fps(frame per second) detection speed are achieved for the1080p(1920×1080) images. Compared with the state-of-the-art work, the detection speed is greatly improved and power consumption is largely reduced. 展开更多
关键词 auto-focus ADABOOST face-priority ARCHITECTURE RECONFIGURABLE
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Small-time sampling behavior of a Fleming-Viot process
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作者 ZHOU YouZhou 《Science China Mathematics》 SCIE CSCD 2017年第3期529-550,共22页
The Fleming-Viot process with parent-independent mutation process is one particular neutral pop- ulation genetic model. As time goes by, some initial species are replaced by mutated ones gradually. Once the population... The Fleming-Viot process with parent-independent mutation process is one particular neutral pop- ulation genetic model. As time goes by, some initial species are replaced by mutated ones gradually. Once the population mutation rate is high, mutated species will elbow out all the initial species very quickly. Small-time behavior in thls case seems to be the key to understand this fast transition. The small-time asymptotic results related to time scale t and a(O)t, where lim0→∞θ θa(θ) = O, are obtained by Dawson and Shni (1998, 2001), Shui and Xiong (2002), and Xiang and Zhang (2005), respectively. Only the behavior under the scale t(θ), where limθ→∞θt(θ) = 0 and limθ→∞(O) =∞ was left untouched. In this paper, the weak limits under various small-time scales are obtained. Of particular interest is the large deviations for the small-time transient sam- pling distributions, which reveal interesting phase transition. Interestingly, such a phase transition is uniquely determined by some species diversity indices. 展开更多
关键词 Fleming-Viot process transient sampling distributions large deviations phase transition
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