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灰色关联分析是对系统发展态势的分析。通过灰色关联分析 ,发现产量与产量性状的关联度为穗长 (y2 ) >每穗粒数 (y3) >千粒重 (y6) >不孕小穗数(y4) >每株穗数 (y3) >植株高度 (y1 ) ,以穗长、每穗粒数对产量影响最大。经模糊综合评判分析发现藏青 3 2 0 >WB0 7— 97>WB1 9— 97>WBQ64— 97,以比较品种WB0 7— 97综合性状表现最好。这说明 ,在西藏冬青稞育种及大田栽培中应选择穗长、每穗粒数多、千粒重高的品种为宜 相似文献
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１０年前利用春小麦的杂交Ｆ３－Ｆ７代材料数据进行和能径分析表明：在产量构成因素中，单穗粒数对单穗粒重、单株产量的影响最大，其次为千粒重，其它性状相对不重要。分析同时证实，西藏春小麦穗粒数与千粒重的相互制约程度不大，相关系数仅为－０．２９６７，未达显著水平，因而较易获得大穗大粒目的。１０年的选育实践证实这一点，选择的藏春１０号，８７０６６７等已开始大面积生产应用。 相似文献
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春玉米种植密度对产量的影响分析 总被引：1，自引：0，他引：1
研究了两个品种吉单209（JD209）、郑单958（ZD958）不同密度群体各生育期LAI动态变化特征,并分析了主要动态特征参数与产量及产量构成的关系,探讨春玉米高密度高产群体叶面积系数（Leaf area index,LAI）动态变化特征对产量的效应。结果表明：各密度群体LAI动态变化呈单峰曲线趋势,随密度增加峰值增大,相同密度下ZD958群体LAI大于ID209,表现较强的耐密性。两个品种高产的适宜密度范围是6万～9万株／hm^2,群体最大LAI在5～7;各生育期的群体LAI与密度呈显著线性正相关,其中抽雄吐丝期LAI对密度的增长率最大,分别为0．583和0．679;灌浆期群体LAI对产量的影响最大,表明此时期是产量形成的关键期。大喇叭口期LAI对穗数、穗粒数影响最大。密度是通过调控群体的LAI和穗数来影响产量构成和最终产量。 相似文献
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《科技风》2017,(25)
为深入了解滇中地区旱地小麦品种农艺性状与产量形成关系,在现有育种和栽培水平的基础上充分挖掘旱地小麦品种生产潜力,提高区域小麦产量,对2006—2016年云南省地麦新品种区域试验中海拔楚雄点147份参试品种进行农艺性状比较分析、相关分析和主成分分析。结果表明:单位面积产量变异系数最大,其次是成穗率有效穗数穗粒数茎蘖数基本苗株高千粒重生育期;单位面积产量与穗粒数极显著正相关,与株高、有效穗显著正相关,与基本苗、茎蘖数不显著负相关;通过主成分分析将9个农艺性状简化为4个主成分,即产量因子、千粒重因子、茎蘖数因子和生育期因子,所提供的信息占总信息量的86.38%。 相似文献
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2007年-2008年,成都农业科技职业学院农场,以LB1768为对照,研究了川麦107、川麦44、川麦36、川农培、SN14951等6个小麦育种材料的穗数,小穗数、千柱重等相关的产量因子,旨在通过比较这三个产量因子,得出该材料的产量构成,从而可作为合适的育种亲本,应用到育种中去。其结果如下：川粳18穗数最多;川麦44小穗数最多,川麦36千粒重最高;产量评比结果是川麦44为最优,这为我们在育种时,根据产量构成的不同来选择合适的育种材料提供了一定的依据。 相似文献
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通过对冬、春青稞、冬、青小麦代表品种的分蘖成穗，幼穗分化，籽粒灌浆规律和产量因于构成特点连续四年的系统观察、比较，分析明确了冬青稞的增产机理。证实：（１）苗期持续时间工，生长缓慢极有利于分蘖发生成穗。（２）幼穗分货物别单棱期比春青稞长１４０和６０多天，从而使三联小穗基分化数猛增。典定了粒多大穗的基础，这是冬稞增产的内在原因。 相似文献
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华北春旱年型对冬小麦影响的模拟试验 总被引：17，自引：1，他引：16
利用大型活动式遮雨棚遮档自然降水,采用人工控制定量喷灌模拟冬小麦生产中3、5、7、10、14a-遇的春旱年型,研究不同春旱年型对冬小麦不同生长发育阶段和产量的影响。试验结果表明：随着春旱年型的增加,冬小麦根、茎、叶、的生长速度明显降低,总生物量减少;春季干旱使冬小麦春生分蘖减少,单位面积总穗数减少,穗长变短,穗粒数减少,千粒重降低,不孕小穗数增加;3、5、7、10、14a－遇春旱处理的冬小麦产量分别比CK减少2.6%、14.6%、22.1%、43.0%、47.2%。春季干旱程度与冬小麦产量呈指数曲线相关。 相似文献
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《西藏科技》2016,(9)
目的探讨拉萨地区气候变暖和青稞黄矮病、条纹病多发情况下,适合主要青稞种植品种藏青2000的播期和种衣剂。方法通过播期、包衣二因素随机区组试验比较研究其对分蘖、产量构成因素、株高、穗长、生育期和倒伏的的影响。结果播期方面:播期一(3月25日)和播期三(4月24日)的产量都显著较高,播期一以穗部要素表现优势,播期三则以茎数和株高表现优势;包衣方面:除株高外,包衣的处理显著高于没有包衣的处理,且P1的千粒重显著高于P2,P2的最高茎数显著高于P1;互作方面:S1P2、S3P1产量较高,S1P2千粒重优势显著、S3P1的茎数和株高优势显著;生长发育方面:S1延长了其生育期,尤其是抽穗-成熟这一生长阶段;倒伏方面:播期越晚倒伏面积越大,倒伏级别越高。结论综合考虑播期、包衣、互作、倒伏等因素,推荐采用3月25日播种且用20%吡虫啉缓释种衣剂包衣(S1P2)的组合。该组合有生育期长、穗粒数和千粒重显著较高、倒伏危害较轻等优点,可以有效保证青稞的高产稳产。 相似文献
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论公共产品类科研资金投入的拟成果购买制 总被引：28，自引：2，他引：28
讨论了目前在中国科研投入上占主导地位的立项拨款制存在的诸多弊端 ;针对这些弊端 ,提出了在公共产品类科研领域将立项拨款制改为以成果决定资金投入的拟成果购买制的制度创新构想 ,该体制使政府对公共产品类科研的管理被简化 ,具有诸多优越性 相似文献
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《Journal of The Franklin Institute》2022,359(5):1795-1820
For a class of large-scale nonlinear time-delay systems with uncertain output equations, the problem of global state asymptotic regulation is addressed by output feedback. The class of systems under consideration are subject to feedforward growth conditions with unknown growth rate and time delays in inputs and outputs. To deal with the system uncertainties and the unknown delays, a novel low-gain observer with adaptive gain is firstly proposed; next, an adaptive output feedback delay-free controller is constructed by combining Lyapunov-Krasovskii functional with backstepping algorithm. Compared with the existing results, the controllers proposed are capable of handling both the uncertain output functions and the unknown time delays in inputs and outputs. With the help of dynamic scaling technique, it is shown that the closed-loop states converge asymptotically to zero, while the adaptive gain is bounded globally. Finally, the effectiveness of our control schemes are illustrated by three examples. 相似文献
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Ningning Wang Tianping Zhang Yang Yi Qin Wang 《Journal of The Franklin Institute》2017,354(13):5176-5200
This paper is concerned with the adaptive control problem of a class of output feedback nonlinear systems with unmodeled dynamics and output constraint. Two dynamic surface control design approaches based on integral barrier Lyapunov function are proposed to design controller ensuring both desired tracking performance and constraint satisfaction. The radial basis function neural networks are utilized to approximate unknown nonlinear continuous functions. K-filters and dynamic signal are introduced to estimate the unmeasured states and deal with the dynamic uncertainties, respectively. By theoretical analysis, the closed-loop control system is proved to be semi-globally uniformly ultimately bounded, while the output constraint is never violated. Simulation results demonstrate the effectiveness of the proposed approaches. 相似文献
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R.E. Faust 《Research Policy》1974,3(2):156-170
As research organizations are asked to assess output and respond to environmental forces demanding productivity and responsiveness to established goals, research managers increasingly seek new approaches to improve overall R & D efficiency. Within pharmaceutical firms research planners and administrators have experimented with several means to generate new insights and techniques aimed at improving the intricate research process. These include such diverse approaches as programs for developing manager-scientists, arranging for technical audits, emphasizing forecasting perspectives, improving government/academic research interactions, seeking extramural new products and promising leads and revising organization and communication patterns. 相似文献
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The paper begins by noting some of the recent proposals for restructuring research activity in British universities, mainly through a process of concentration of research resources. We then review the available evidence, which shows that there is little support for such concentration except in the most resource-intensive disciplines. Since there is little firm information about the shape of “research production functions’, either for institutions or for the system as a whole, the core of the paper studies the factors likely to be important in such functions and investigates the consequences of particular functional forms. Finally, it is concluded that more research is needed to gain a better understanding of the research process in universities, and that in the meantime it would be unwise to embark on a wholesale restructuring of the system. 相似文献