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1.
ABSTRACT

The present study was conducted to assess the ability of AquaCrop model in predicting of grain and biological yield of rice genotypes in water management. A two-year field experiment was conducted at the experimental farm of the Iranian Rice Research Institute in Rasht, Iran from 2016 to 2017. The experiment was established in a split-plot design with two irrigation management (continuous submergence and end season water stress) as the main plot, fourth rice genotypes as the sub-plot and three replications. The goodness-of-fit between observed and simulated grain yield and final biomass was assessed by means of the coefficient of determination (R 2), the absolute and normalized root mean square errors (RMSE). The RMSEn of predicting grain yield at calibration and evaluation stages was in the range of 6–12% and 6–8% for biological yield. The results indicated that AquaCrop model is suitable to predict grain yield and biological yield of rice genotypes in northern Iran. AquaCrop model can be used to determine optimization strategies to improve the water consumption of rice genotypes.  相似文献   
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The pathogenicity of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae against the tick fowl Argas persicargas persicus was studied. Bioassays revealed significant differences between the two fungi and the A. persicargas persicus stages exposed. The first nymphal instar was more highly susceptible to both fungi than the second nymphal instar. The unfed female of A. persicargas persicus was significantly less susceptible to both fungi than the engorged female. Application of M. anisopliae to sackcloth naturally infested with the tick fowl A. persicargas persicus induced mortality which reached 100?% three weeks after treatment under field conditions. The present study suggests that entomopathogenic fungi have good potential for tick fowl, A. persicargas persicus, control.  相似文献   
4.
The influence of assimilate supply, metabolism and dilution on sugar concentrations in the mesocarp of peach (Prunus persica (L.) Batsch) fruit during the main stage of fruit enlargement was analyzed with the SUGAR model of Génard and Souty (1996). The model predicts the partitioning of carbon into sucrose, sorbitol, glucose and fructose in the mesocarp of peach fruit. Based on measured data and the model, we determined values for the relative rates of sugar transformation. These rates were constant, varied with time or varied with relative fruit growth rate, depending on the type of sugar. Equations were derived to describe these rates and incorporated into the SUGAR model. The model simulated the effects of changing assimilate supply and fruit volume on sugar concentrations. The set of equations for the SUGAR model was rewritten to include the three components influencing sugar concentrations: assimilate supply, metabolism and dilution. The sugar types differed in sensitivity to these components. Sucrose was highly sensitive to changes in assimilate supply and to the dilution effect; it was not subject to intense metabolic transformation. Sorbitol was the most important carbohydrate in fruit metabolism, which explains why the sorbitol concentration was always low despite the strong positive effect of assimilate supply. The reducing sugars constituted a transitory storage pool and their concentrations were closely related to metabolism.  相似文献   
5.
Shoot development was studied for two consecutive years in peach trees fertilized with N either in the previous fall or in the middle of the growing season. During the first year, two additional treatments were studied: no N supply and nitrate supplied in the irrigation water throughout the growing season. The number of shoots that developed depended on nitrogen availability in the period following bud break. During shoot development, leaf emergence occurred in one, two, or three stages, which ended at about 500 to 600 degree days, 1,000 to 1,200 degree days, and 1,500 to 2,000 degree days after bloom, respectively. The proportion of shoots exhibiting a second or third developmental stage depended on nitrogen availability at the beginning of that stage. Increasing nitrogen availability during a developmental stage prolonged the stage and increased the number of leaves produced.  相似文献   
6.
【目的】研究枣实蝇在寄主植物果实不同发育期的危害程度对其最佳防治期。【方法】分析枣园对不同寄主枣树样枝套袋枣实蝇的蛀果率,调查虫口密度;室内饲养测定果实不同发育期对枣实蝇生长发育和繁殖的影响,分析和评价枣实蝇对不同发育期骏枣和酸枣果实的生物学响应变化。【结果】枣实蝇对骏枣果实的蛀果率均大于对酸枣的蛀果率,并且枣实蝇在骏枣果实成熟期蛀果率为最大;成熟期骏枣上的虫口密度也最大;骏枣上雌虫产卵痕数、幼虫数和卵的孵化率均大于酸枣上的枣实蝇。在枣果着色期和成熟期,蛹的各项生长指标均高于膨大期;果实不同发育期,骏枣上的蛹各项生长指标均显著大于(P<0.05)酸枣上的;骏枣上枣实蝇的蛹期、雌虫怀卵量、性成熟历期、交配时间以及雌雄成虫寿命均略大于酸枣,但无显著差异(P>0.05)。【结论】枣实蝇对骏枣的选择性强于酸枣,并且成熟期的骏枣果实更适宜枣实蝇生长发育。  相似文献   
7.
【目的】研究新疆盐碱环境中耐盐植物白刺的根际土壤和叶片内生微生物群落的结构丰富度和多样性。【方法】运用Novaseq测序平台对白刺根际土壤和叶片进行16SrDNA-V4区和ITS1区测序。经FLASH进行拼接,经过Qiim过滤叶绿体和线粒体序列,得到的序列在97%的序列相似性水平上聚类成为操作分类单元(OTUs)。对序列数据进行生物信息学分析,评价物种的Chao1指数、shannon指数以及Alpha多样性。【结果】白刺根际土壤细菌优势菌群为放线菌门(Actinobacteria)、变形菌门(Proteobacteria)、芽单胞菌门(Gemmatimonadetes);真菌优势菌群为子囊菌门(Ascomycota)。叶片内生细菌优势菌群为蓝细菌门(Cyanobacteria)和放线菌门(Actinobacteria);真菌优势菌群为子囊菌门(Ascomycota),白刺不同部位的微生物菌群数量和多样性有显著差异(P<0.05),白刺各样地之间微生物群落构成差异明显。【结论】白刺不同部位微生物群落的丰富度和多样性分布。  相似文献   
8.
Aquaculture International - A 56-day study was carried out to examine the addition of live foods a biofloc technology (BFT) system on Penaeus vannamei postlarvae performance (PL25, initial weight:...  相似文献   
9.
Zagros forests are mainly covered byQuercus brantii L. coppices and oak sprout clumps occupy the forest area like patches. We investigated post-fire herbaceous diversity in the first growing season after fire. For this purpose neighboring burned and unburned areas were selected with the same plant species and ecological conditions. The data were collected from areas subjected to different fire severities. Overall 6 treatments were considered with respect to fire severity and the mi-crosites of inside and outside of oak sprout clumps including: unburned inside and outside of sprout clumps (Ni and No), inside of sprout clumps that burned with high fire severity (H), inside of sprout clumps that burned with moderate fire severity (M), outside of sprout clumps that burned with low fire severity (OH and OM). Different herbaceous com-position was observed in the unburned inside and outside of oak sprout clumps. The species diversity and richness were increased in treatments burned with low and moderate fire severity. However, in treatment burned with high fire severity (H), herbaceous cover was reduced, even-ness was increased, and richness and diversity were not significantly changed. We concluded that besides the microsites conditions in forest, fire severity is an inseparable part of the ecological effect of fire on her-baceous composition.  相似文献   
10.
The interaction between particle size and resin content is one of the most important structural parameters that can influence the accuracy of predictions about wood-composite properties. We developed three kinds of equation (linear, quadratic, and exponential) for each mechanical property of particleboard based on slenderness ratio and resin content at a constant density (0.7g cm -3 ). Results from SHAZAM software (version 9) suggested that the quadratic function was not significant, but the linear and exponential functions were significant. The interaction between particle size and resin content was analyzed by Maple 9 software. The results indicated that an exponential function can better describe the simultaneous effect of slenderness and resin content than a linear equation. Under constant resin content, particles with higher slenderness ratios increased more in modulus of rupture (MOR) and modulus of elasticity (MOE) than did particles with lower slenderness ratios. Edge withdrawal resistance (SWRe) values did not increase with increasing slenderness ratio.  相似文献   
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