基于掖478导入系的玉米产量性状QTL鉴定

 目的】鉴定玉米产量相关性状基因位点及包含有利等位基因的导入系,为了解产量性状形成的遗传基础及针对玉米自交系产量性状的分子设计提供参考和依据。【方法】以QB80和Qi319为供体亲本,掖478为轮回亲本,采用回交结合定向选择,分别构建含有61和72个家系的基础导入系群体。通过2年4点田间试验,利用完备复合区间作图进行产量及其相关性状的QTL（quantitative trait locus,QTL）分析。【结果】4个环境下,在QB80为供体的导入系群体中,共检测到9个性状的49个QTL;在Qi319为供体的导入系群体中,检测到9个性状的42个QTL。在2个及以上环境中均检测到的QTL有16个。同一性状在不同环境下所检测的QTL定位在相同的染色体区域,不同性状的QTL也定位在相同或临近的染色体区域,形成多个QTL富集区。2个群体所检测的QTL位点具有较少的一致性,说明2个供体材料中含有不同的有利基因位点。同时,导入片段中含有利基因的导入系,其相关性状明显得以改良,这些导入系可用于QTL聚合以改良掖478的产量相关性状。【结论】QB80较Qi319与掖478间的遗传差异更大,能检测更多的产量性状QTL;2个导入系群体中含有优良等位基因的导入系可用于QTL聚合改良掖478;QTL富集区是为产量性状基因的克隆提供可供参考的重要染色体区域。     

崇明白山羊遗传多样性的ISSR分析

应用ISSR分子标记对崇明白山羊3个群体和黄淮山羊群体进行遗传多样性分析。用筛选出的12条引物对127个个体进行扩增,共扩增出147条谱带,其中多态性谱带67条。分析结果显示:崇明白山羊遗传多样性较为丰富,在物种水平上平均多态位点百分率(PPB)=42.18%,Shannon's信息指数(Ho)=0.2085;在群体水平上,PPB=38.55%,Ho=0.1946。崇明白山羊各群体间遗传差异较小,遗传稳定性较高。UPGMA聚类分析显示:崇明白山羊3个群体间亲缘关系较近,优先聚为1支,再与黄淮山羊相聚。     

Optimization of an artificial neural network topology using coupled response surface methodology and genetic algorithm for fluidized bed drying

In this study, an integrated response surface methodology (RSM) and genetic algorithm (GA) are recommended for developing artificial neural networks (ANNs) with great chances to be an optimal one. A multi-layer feed forward (MLFF) ANN was applied to correlate the outputs (energy and exergy) to the four exogenous inputs (drying time, drying air temperature, carrot cubes size, and bed depth). The RSM was used to build the relationship between the input parameters and output responses, and used as the fitness function to measure the fitness value of the GA approach. In the relationship building, five variables were used (number of neurons, momentum coefficient and step size in the hidden layer, number of epochs and number of training times). A polynomial model was developed from training results to mean square error (MSE) of 50 developed ANNs to generate 3D response surfaces and contour plots. Finally, GA was applied to find the optimal topology of ANN. The ANN topology had minimum MSE when the number of neurons in the hidden layer, momentum coefficient, step size, number of training epochs and training times were 28, 0.66, 0.35, 2877 and 3, respectively. The energy and exergy of carrot cubes during fluidized bed drying were predicted with R² values of greater than 0.97 using optimal ANN topology.     

A morphological assessment system for ‘show quality’ bovine livestock based on image analysis

Morphological assessment is one important parameter considered in conservation and improvement programs for bovine livestock. This assessment process consists of scoring an animal based on its morphology and is normally carried out by highly qualified staff. These animals are all of agreed ‘show quality’ and hence they are morphologically very similar.This paper presents a system designed to provide an assessment based on a lateral image of the cow. The system consists of two main parts: a feature extraction stage, to reduce the information on the cow in the image to a set of parameters, and a neural network stage to provide a score based on that set of parameters. For the image analysis section, a model of the animal is constructed by means of the point distribution model (PDM) technique. Later, that model is used in the searching process within each image, which is implemented using genetic algorithms (GAs). As a result of this stage, the vector of weights that describe the deviation of the given shape from the mean is obtained. This vector is used in the second stage, where a multilayer perceptron is trained to provide the desired assessment, using the scores given by experts for selected cows.The system has been tested with 138 images corresponding to 44 individuals of a special rustic breed, with very promising results, given that the information contained in only one view of the cow can not be considered complete.     

基于遗传算法优化BP神经网络的小球藻生长模型的建立与应用

[目的]探讨用遗传算法优化BP神经网络对小球藻生长模型的建立与应用。[方法]使用遗传算法对BP神经网络的权值和阈值进行优化,并使用该网络模型,以小球藻培养时间和残余葡萄糖为输入,菌体光密度值（OD680）为输出,对小球藻在500 L多功能生物反应器中的生长情况进行了建模,还探讨了该模型的应用情况。[结果]经过遗传算法优化的BP神经网络,其泛化值的误差平方和比BP神经网络的小,因而预测值更加接近实际值。t检验表明,所建立的模型是可信的。验证表明,该模型具有良好的拟合度,能够很好地描述在500 L多功能生物反应器中培养的小球藻的生物量（OD680）与残余葡萄糖和培养时间之间的关系。[结论]所建立的模型可用于试验结果的预测,对小球藻的培养控制具有指导意义。     

应用RAPD分析亚麻种质资源遗传多样性研究

[目的]对40份亚麻种质资源进行分类。[方法]通过RAPD技术分析,利用类平均法（UPGMA）进行了聚类分析。[结果]从供试材料中筛选出11条具有多态性的RAPD引物。RAPD引物共扩增到71条清晰的多态性条带,多态性比率为88.8%。对标记结果进行了UPGMA聚类分析,聚类结果表明地理位置相近的品种聚为一类。[结论]为大批量亚麻种质资源的鉴定和分类以及资源的有效利用提供了理论依据。     

不同遗传基础肉牛增重效果和血液指标的比较研究

[目的]研究遗传基础、营养水平及其互作对杂交肉牛增重效果及血液指标的影响。[方法]试验采用4×2双因子试验设计,选取4种不同遗传基础肉牛（夏洛来牛、德国黄牛、红安格斯牛和利木赞牛）分别与西杂母牛杂交的后代44头,饲喂2种不同营养水平日粮,试验期为140 d。[结果]在低营养水平下,安西杂牛的日增重显著高于夏西杂牛（P〈0.05）。在高营养水平下,利西杂牛的白蛋白含量极显著高于夏西杂牛和德西杂牛（P〈0.01）;在低营养水平下,利西杂牛的白蛋白含量显著高于德西杂牛（P〈0.05）。在高营养水平下,利西杂牛的总蛋白含量显著高于夏西杂牛（P〈0.05）;安西杂牛的甘油三酯含量显著高于德西杂牛（P〈0.05）;夏西杂牛的乳酸脱氢酶活性显著高于德西杂牛（P〈0.05）。在低营养水平下,利西杂牛的尿素氮含量显著高于夏西杂牛和安西杂牛（P〈0.05）;安西杂牛的尿素氮含量,高营养组极显著高于低营养组（P〈0.01）。在低营养水平下,利西杂牛的碱性磷酸酶活性极显著高于安西杂牛（P〈0.01）,显著高于夏西杂牛和德西杂牛（P〈0.05）;低营养组利西杂牛的碱性磷酸酶活性显著高于高营养组（P〈0.05）。[结论]杂交牛的日增重、碱性磷酸酶活性和乳酸脱氢酶活性受遗传因素影响显著,白蛋白和尿素氮含量受遗传和营养双重因素影响。     

复合型生物农药的研究进展

对生物农药的发展历程进行了概述,从复合型生物杀虫剂和除草剂2个方面阐明了生物农药存在的问题和未来的发展趋势,并对复合型生物农药在未来农药领域的发展前景进行了展望。     

阿维菌素高产菌的育种研究进展

阿维菌素是阿维链霉菌产生的具有杀虫活性的大环内酯类抗生素,在农业和畜牧业中应用广泛。对近年来的研究概况,从产特定组分阿维茵素菌种选育、阿维菌素高产菌选育和阿维菌素的改造创新等方面进行了综述。     

宁夏常用玉米自交系的SSR遗传分析

[目的]对宁夏常用的82份玉米（Zea may L.）自交系进行遗传分析,划分自交系类群,以提高玉米育种效率。[方法]利用SSR标记中可用于遗传多样性分析的20对SSR引物对材料进行分析。[结果]82份自交系中共检测出335个等位基因,其中具有多态性的为108个,每对引物检测出3～10个多态性位点,平均为5.4个。SSR引物的多态性信息量（PIC）介于0.523 3～0.858 9,平均为0.7123。[结论]82份自交系划分为5个类群,分类结果基本与系谱来源一致。