棉花黄萎病菌分子生物学研究新进展

本文以分子生物学研究手段为纲 ,从RFLP、RAPD、ITS等方面 ,综述了国内外在棉花黄萎病菌种内划分及致病力分化上的研究状况及最新进展     

移动式低温烘干机干燥晚籼稻生产性试验

本文对移动式低温烘干机干燥晚籼稻进行了生产性试验，对其应用效果和使用过程中存在的问题客观科学地加以分析研究，从中积累经验，为进一步应用提供了技术支持。     

现代农业内涵、特征及发展趋势

现代农业是基于现代产业组织和现代涉农产业系统的培育与完善,横跨一、二、三产业的涉农经济体系,与发达国家农业总产值中占有重要比重的涉农产业(Agribusiness)相当。在科学界定现代农业概念与内涵的基础上,梳理国际涉农产业发展的实践与发展趋势,具有积极的理论和现实意义。     

cDNA-AFLP技术及在差异表达基因克隆上的应用

cDNA-AFLP技术是在AFLP技术基础上发展起来的主要用于研究基因差异的技术，具有高效可靠的优点，受到研究者的青睐，被广泛应用于包括植物在内的各类生物的基因表达的研究中。简要阐述了cDNA-AFLP技术的原理，重点讨论了操作过程中可能出现的问题和技术关键，并就该技术与其他差异表达技术进行了比较，以说明其在克隆差异表达基因上的优势，还简要列举了一些在抗病育种等领域的应用实例。     

基因组原位杂交技术在植物研究中的应用

基因组原位杂交是以亲本之一的总基因组DNA做探针,另一亲本的基因组DNA做封阻,在荧光原位杂交技术的基础上发展起来的一种染色体/染色质检测技术。在其发展的十几年里,已在植物的基因组研究中发挥了重要的作用。应用这一技术可对多倍体中基因组之间的亲缘关系、基因组组成及起源进行研究;对杂交种中染色体组的组成进行分析;对代换系、附加系和易位系进行有效的鉴定,并对其中的外源染色体或染色体片段的来源、大小、数目及发生位点进行检测和定位。此外,利用基因组原位杂交技术还有助于确定物种间的同源性;研究杂交种中来源不同的染色质在核中的分布;探索B染色体的起源、染色体间的配对、重组、交换等现象。随着基因组荧光原位杂交技术体系的不断发展、完善和改进,其应用范围不断拓展,在植物基因组研究领域中发挥了越来越重要的作用。     

Multivariate Extension of Griffing's Diallel Analysis

Diallel-cross designs have been used extensively in plant and animal breeding programs. In most cases, multiple traits are measured in the study, but the analyses are performed on each trait separately. The objective of this paper is to provide an alternative multivariate procedure so that the combining abilities among traits can be evaluated simultaneously and the interaction of combining ability and traits can be tested statistically.
Numerical example is provided from data of a rice study. Three characters, panicles per plant, percent sterility, and 100 kernel weight were used in the analysis. Results showed that some parental lines with greater combining abilities in one trait may not be so good in another trait. Also certain crosses may be better for one trait but not necessarily as good for other traits.     

Study on Simulation of Contact Friction Condition of Continously Variable Transmission

As metal Belt CVT(Continuously Variable Trans mission) acts as a kind of friction transmission, friction coefficient is a key parameter of CVT. The friction characters of CVTF(Continuously Variable Transmission Fluid) are mainly determined by fluid and contact state. The contact between belt and pulley can be regarded as a kind of contact between cylinder and cone. As their contact line is short, the curvature change of pulley along the contact line can be neglected. Then the contact problem of belt and pulley was reasonably simplified as a contact between cylinder and cylinder. Under the state of equivalent maximum stress, the contact friction condition of metal belt and pulley was simulated by the contact of ring and block in Timken Friction Test Machine.     

Genetic analysis of four self-incompatible lines in Brassica napus

Reciprocal hybridization between four self-incompatible lines of Brassica napus: 271, 181, 184 and ‘White Flower’, revealed incompatibility. The reciprocal F₁s obtained by bud pollination showed self-incompatible reactions, and no segregation for self-incompatibility was observed in all the reciprocal F₂ populations, indicating that lines 271, 181, 184 and ‘White Flower’ were genetically identical with regard to self-incompatibility. Observations of self-incompatibility in 17 hybrids from crosses between line 271 and 17 varieties of B. napus showed 10 of the F₁ hybrids to be self-compatible, while four were partially self-compatible and three were self-incompatible. Genetic analysis based on F₂ and BC₁ populations from five self-compatible F₁ hybrids and two self-incompatible F₁ hybrids suggested the existence of at least two loci controlling the self-incompatibility of line 271: one is the S locus, with dominant and recessive relationships between the S alleles, and the other is the suppressor (sp) of the S locus. The sp locus is genetically different from the S locus, and also shows dominant and recessive relationships between the sp alleles.     

玉米苗期的耐冷性状及其遗传力的研究

本文利用6个自交系按6×6不完全双列杂交组配的15个F_1为材料,对出苗率、出苗指数、电解质外渗量等11个与玉米苗期耐冷性有关的性状进行通径分析和遗传分析表明:在所有被测性状中,出苗率、出苗指数、幼苗鲜重、干物质增长量、组织活性对玉米幼苗耐冷性的影响是直接的,幼苗干重、种子百粒重、电解质外渗量对玉米苗期耐冷性的影响是间接的;出苗率、出苗指数、幼苗干重、干物质增长量四性状在遗传上主要受加性效应影响.根据以上结果提出,上列性状都应作为玉米耐冷性育种的改良目标.     

基于地质统计学影像纹理的石河子地区化控期棉花长势监测

化学调控是棉花生长期间的一个重要环节，在较大区域尺度上，化控常常整齐划一，依固定的量而行，忽视其普遍存在的空间差异，结果导致某些棉田投入过量或投入不足，在精细农业所倡导的基于特定场的农业投入这一框架下，为辅助决策者制定有针对性的棉田化控方案，该文提出了应用地质统计学影像纹理进行对化控棉花长势监测，通过借助地质统计学方法在分析空间结构变化上的优势，强化遥感影像上不同长势棉田间的差别，提高样本选择的分离度和长势空间分类精度。实验结果表明，运用变异函数纹理结合光谱波段的最大似然分类方法能够很好地界定棉花长势的不同类型，总分类精度达90.53%，证明了应用地质统计学影像纹理方法在针对化控的棉花长势监测上的有效性。