Simulating the Production of Rice Genotypes by Flood Management and End-Season Water Stress Conditions Using AquaCrop Model

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 RMSE_n 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.     

Nutrients management strategies to improve yield and quality of sugar beet in semi-arid regions

The objective of this study was to evaluate the effects of organic and inorganic fertilizers on the yield and quality of sugar beet genotypes (Beta vulgaris L.). Therefore, a field trial was carried out in Peshawar, Pakistan, during the winters in 2012–2013. The field experiment was conducted in a randomized complete block design with split plots, having three replications. Fertilizer treatments (control, composted manure Higo Organic Plus at 5 t ha^?1, Maxicrop Sea Gold seaweed extract at 5 L ha^?1, farm yard manure at 10 t ha^?1, inorganic nitrogen–phosphorus (NP) at 90:60 kg ha^?1, NP at 120:90 kg ha^?1 and NP at 150:120 kg ha^?1) were allotted to main plots, while genotypes (Sandrina, Serenada and Kawe Terma) were allotted to the sub-plots. Plots treated with the application of NP at 120:90 kg ha^?1 produced the highest beet yield (76.4 t ha^?1) and sugar yield (11.1 t ha^?1), and had the second highest polarizable sugar content (14.52%) and more economic return (Rs. 553,000 per hectare) as compared to control plots. Sugar beet genotype Serenada had significantly higher beet yield (55.5 t ha^?1) and sugar yield (7.9 t ha^?1) and a higher economic return (Rs. 380,000 per hectare) than the other genotypes. Sugar beet genotype Serenada supplied with NP at 120:90 kg ha^?1is recommended for the general cultivation in the agro-climatic conditions of Peshawar valley.     

Effects of ambient gaseous pollutants on photosynthesis,growth, yield and grain quality of selected crops grown at different sites varying in pollution levels

In recent decades, ambient gaseous pollution has increased due to anthropogenic activities worldwide. The studies to evaluate the adverse effects of ambient pollutants on commonly grown food crops are still limited, especially in Asian countries like Pakistan. The present study was conducted to measure the ambient pollutants in different sites of Faisalabad and their impact on growth and yield of wheat, mung bean and peas. Plants were grown in pots and placed at three sites named as control (Wire house of Government College University, Faisalabad), low pollution (LP) (Farm Area of Ayub Agricultural Research Institute) and high pollution (HP) (GT Chowk, Faisalabad) sites. Results showed that ambient ozone (O₃) concentration was highest at HP site followed by LP site and was below AOT40 in control site. Ambient pollutants caused foliar injury in crops and decreased plant height, leaf area, biomass and grain yield. Pollutants caused a reduction in photosynthetic pigments, stomatal conductance and net photosynthetic rate and grain protein contents in all three crops. In conclusion, the ambient O₃ level was highest at HP site, this current O₃ level and other pollutants decreased the growth and yield of important food crops.     

Boron-Calcium Synergically Alleviates Aluminum Toxicity in Wheat Plants (Triticum aestivum L.)

The effects of B and Ca treatments on root growth, nutrient localization and cell wall properties in wheat ( Triticum aestivum L.) plants with and without Al stress were investigated. Seedlings were grown hydroponically in a complete nutrient solution for 7 d and then treated with B (0, 40 μM), Ca (0, 2,500 μM), and Al (0, 100 μM) in a 500 μM CaCl₂ solution for 8 d. The cell wall materials (CWM) were extracted with a phenol: acetic acid: water (2:1:1 w/v/v) solution and used for subsequent pectin extraction with trans -1,2-diami-nocyclohexane- N,N,N,N -tetraacetic acid (CDTA) and Na₂CO₃ solutions. Boron, Ca, and B + Ca treatments enhanced root growth by 19.5, 15.2, and 27.2%, respectively, compared to the control (pH 4.5). Calcium and B+Ca treatments enhanced root growth with Al stress by 43 and 54%, respectively, while B did not exert any effect. The amounts of CWM and pectin per unit of root fresh weight increased by Al treatment, whereas the Ca and B+Ca treatments slightly reduced the contents of these components. Seventy-four percent of total B, 69% of total Ca, and 85% of total Al were located in the cell wall in the B, Ca, and Al treatments, respectively and 32% of total B, 33% of total Ca, and 33% of total Al were located in the CDTA-soluble and Na₂CO₃-soluble pectin fractions. A more conspicuous localization of B was observed in the presence of Al. Aluminum treatment markedly decreased the Ca content in the cell wall as well as pectin fractions, mainly in the case of the CDTA-soluble pectin fraction. Boron + Ca treatment decreased the Al content in the cell wall and pectin fractions compared to the Ca treatment alone in the presence of Al. It is concluded that the B+Ca treatment enhanced root growth and, B and Ca uptake, and helped to maintain a normal B and Ca metabolism in the cell walls even in the presence of Al.     

Genetic tracking of the brown bear in northern Pakistan and implications for conservation

Asian bears face major threats due to the impact of human activities as well as a critical lack of knowledge about their status, distribution and needs for survival. Once abundant in northern Pakistan, the Himalayan brown bear (Ursus arctos isabellinus) has been exterminated in most of its former distribution range. It presently occurs sparsely, in small populations, the Deosai National Park supporting the largest isolate. This decline might imply a reduction in genetic diversity, compromising the survival of the population. Using a combination of fecal DNA analysis and field data, our study aimed at assessing the size and genetic status of the Deosai population and give guidelines for its conservation and management. Using fecal genetic analysis, we estimated the population to be 40-50 bears, which compares well with the field census of 38 bears. The northern Pakistani brown bear population may have undergone an approximate 200-300-fold decrease during the last thousand years, probably due to glaciations and the influence of growing human population. However, in spite of the presence of a bottleneck genetic signature, the Deosai population has a moderate level of genetic diversity and is not at immediate risk of inbreeding depression. Gene flow might exist with adjacent populations. We recommend careful monitoring of this population in the future both with field observations and genetic analyses, including sampling of adjacent populations to assess incoming gene flow. The connectivity with adjacent populations in Pakistan and India will be of prime importance for the long-term survival of Deosai bears.     

从多毛野生番茄中初步鉴定出一个抗美洲斑潜蝇的显性基因

美洲斑潜蝇(LiriomyzasativaeBlandchard)是危害番茄生产的主要害虫之一,从番茄近缘野生种中挖掘优异的抗斑潜蝇基因,并研究抗虫基因的遗传,是番茄抗虫遗传改良的重要基础。将筛选到的高抗美洲斑潜蝇的野生多毛番茄(L.hirsutum)材料LA2329,与高感美洲斑潜蝇栽培番茄早粉2号杂交,并用早粉2号为母本与杂种F1回交,通过对各世代抗斑潜蝇的人工接种鉴定,初步判定该抗性由单显性基因控制。番茄属中由单显性基因控制的对斑潜蝇抗性,目前尚未见报道。该抗性基因的发现,将为今后番茄抗斑潜蝇育种提供宝贵资源,有望在不远的将来通过标记辅助育种手段而引入栽培番茄,为我国番茄生产中害虫的防治提供环保、经济而有效的科技支撑。     

基于ANSYS Workbench的乘坐式割草机刀盘模态分析

刀盘是割草机重要部件,其工作时固有频率与振型的大小直接关系到整机的可靠性与安全性。为此,利用CAD/CAM软件Pro/E建立刀盘的三维实体模型,并将其导入有限元分析软件ANSYS Workbench,对所建模型进行模态有限元仿真分析,提取前6阶固有频率,与刀盘转速进行比较,计算出其工作时的危险转速范围。分析结果表明:刀盘最高工作转速远低于其1阶临界转速,有效地避免了共振的发生,验证了刀盘设计的合理性,可为刀盘其它的动力学分析奠定基础。     

基于自适应全局阈值融合标记的遥感图像建筑群分割

针对分割遥感图像建筑群时,标记不完全所产生的过分割和欠分割并存问题,提出一种基于自适应全局阈值融合标记的图像分割算法.该算法根据建筑群的分布和纹理特点,利用小波变换提取图像梯度,通过形态学重构对梯度图像进行滤波;采用局部极小值法提取背景标记,并应用自适应全局阈值法提取建筑群标记.采用逻辑运算进行标记融合,用融合后的标记修改加权像素的Sobel梯度图实现精准分割.实验结果表明,该算法能够弥补形态学滤波梯度图的局部极值标记不足问题,抑制了建筑群的过分割和欠分割,准确地将建筑群从背景中提取出来,分割正确率达到90.7％.     

Toxic Effect of Certain Metals Mixture on Some Physiological and Morphological Characteristics of Freshwater Algae

The toxic effect of multi metals mixture which exist simultaneously in aquatic ecosystem on natural phytoplankton assemblages (green algae, blue-green algae and diatoms) was studied. For this purpose a laboratory scale unit was designed to evaluate the effect of continuous flow metals mixture in forms if triple and penta metals in Nile water algae. Clear changes in algal biomass in terms of chlorophyll a (chl a) took place when subjected to metals combination. The rise or decline in chl a was in relation with other algal pigments (chl b, chl c, carotenoides and phenophytin), protein and carbohydrate content of algal cells. Substantial changes in phytoplankton community structure was detected and the most tolerant group was blue-green algae followed by green algae while diatoms was the most sensitive group. The most dominant species in all cases were blue-green alga Oscillatoria mougeotii and green alga Scenedesmus quadricauda. In addition clear changes in morphological shape was observed for tolerant species belonging to the three algal groups. Nile water algae has ability to remove and accumulate metals in the following order therefore Zn > Cd > Ni > Cu > Cr. In addition, phytoplankton has ability to recovered from the stress of metals when eliminated from the media and the recovered biomass was nearly equivalent to that before exposing to metals stress. The overall effect of metals mixture depending on the type and number of metals, the algal community structure and ratio between different morphological forms of algae (unicellular, colonial and filamentous).     

确定潜水含水层系统参数的Boulton-RAGA方法

在对考虑迟后排水的N.S.Boulton第二潜水井流模型解析解分析的基础上，将复合高斯求积法和具有随机搜索寻优特性的实数编码加速遗传算法(RAGA)相结合对其进行优化求解，提出了确定潜水含水层系统参数的Boulton-RAGA法。以计算实例表明，Boulton-RAGA法可以取得很好的求参效果，并且与传统方法比较，方法简单，快速，不需要分抽水时间——降深过程的前、后段进行参数确定，大大简化了潜水含水层的参数确定过程，对于缩短抽水时间确定含水层系统参数具有重要的意义。