Mapping QTL involved in adult plant resistance to powdery mildew in the winter wheat line RE714 in two susceptible genetic backgrounds

The objective was to study the genetic basis of adult plant resistance to powdery mildew of the winter wheat line RE714 by quantitative trait loci (QTL) analysis and to investigate the stability of the QTL detected in two different genetic backgrounds. Two DH populations from the crosses between RE714 and the susceptible parents ‘Festin’ and ‘Hardi’ were used. Reaction of the DH lines to powdery mildew was assessed in different environments in Belgium under natural disease infection. Considering both populations and according to the environment tested, one to seven QTL were detected. Among them, residual effects of the race‐specific resistance genes Pm4b and MIRE were found. Two major QTL were very stable (on chromosome 5D and at the MIRE locus), since they were detected in both populations and over all environments tested. The QTL detected varied according to the susceptible parent used, and a residual effect at the Pm4b gene was not observed with the genetic background of ‘Hardi’.     

Genes Lr48 and Lr49 for hypersensitive adult plant leaf rust resistance in wheat (Triticum aestivum L.)

The genetic bases of leaf rust resistance in wheat (Triticum aestivum L.) line CSP44, selected from the Australian cultivar Condor, and Indian cultivar VL404, were studied. The reaction patterns of CSP44 and VL404 against Indian races 12, 77, 77-1, 77-2, 77-3, 77-4, 77-5 and 108 were different from reaction patterns shown by near-isogenic lines with known adult plant resistance (APR) genes, viz. Lr12, Lr13, Lr22b and Lr34. Although the reaction patterns of CSP44 and VL404 were similar to the near-isogenic line Tc+Lr22a, tests of allelism indicated absence of Lr22a in both CSP44 and VL404. On the basis of genetic studies, their resistances in field tests against race 77-5, the most virulent race from the Indian sub-continent, were each ascribed to two genes. One of the two genes in each wheat was identified to be the non-hypersensitive APR gene Lr34. The second APR genes in CSP44 and VL404 gave hypersensitive reaction types and were recessive and dominant, respectively. The gene in CSP44 was designated Lr48and the gene in VL404, Lr49. This revised version was published online in August 2006 with corrections to the Cover Date.     

论重点高校办高职教育

高职教育是培养面向基层、面向生产、管理、服务一线的高级应用型人才的教育，对促进经济建设、社会发展具有重要意义。重点高校是否举办高职教育，如何办出高职特色？本方通过自身的力学体会，对上述问题进行了阐述，并希望通过研讨这类问题，促进重点本科院校的高职教育发展。     

红锥切根育苗试验研究

通过红锥切根、沾灰育苗试验，分析成苗率、苗高、地径、主根、须根及枝、叶等一系列苗木数量、质量性状的差异。结果表明：切根能使红锥苗木主根变短，侧根部位提高，根系发达，苗木地径和苗高明显增加，生长旺盛。但切根也在一定程度上降低了成苗率。     

干细胞及其在人类医学上的应用前景

干细胞是指从胚胎、胎儿或成年个体各种组织中分离出来的多能性细胞 ,具有体外保持未分化状态的无限增殖能力 ,在不同条件下可诱导分化为不同的细胞类型、组织甚至器官。胚胎癌细胞、胚胎干细胞、胚胎生殖细胞和成年组织干细胞是目前研究的几类主要干细胞 ,它们除作为发育生物学研究的细胞模型外 ,在人类医学领域也具有潜在的应用价值     

中介语石化现象对成人英语学习的影响

中介语又称"过渡语"。中介语石化现象是近20年来二语习得研究的重要课题之一。石化现象对成人英语学习的影响主要表现在词汇、惯用语和句子的汉式表达上。     

丹顶鹤早期生长发育规律的初步研究

对 6只幼鹤 (初生及 1～ 1 3周 )的体重、体尺和 9只成鹤的体尺进行测定 ,将幼鹤体重、体尺测定结果拟合生长曲线方程 ,并与成鹤的体尺指标进行比较。结果表明 :幼鹤早期生长发育阶段可划分为 3个时期 :第 1时期 (0～ 2周龄 )是快速生长期 ,第 2时期 (3～ 7周龄 )是急速生长期 ,第 3时期 (8～ 1 3周龄 )是缓慢生长期。Logistic生长曲线方程能很好地拟合丹顶鹤早期的生长发育 ,拟合精度 (R2 )均大于 0 .9955。幼鹤 1 3周龄时各项体尺指标均达到成鹤的 86%以上 ,并呈现出体长较体宽发育快的特点     

成体干细胞的可塑性

传统观念认为,成体干细胞只能分化成其自身来源组织的细胞类型。但近年大量的研究表明,成体干细胞可跨系甚至跨胚层分化成在发育上与之无关的其他组织的细胞类型,即具有可塑性。文章对成体干细胞可塑性的研究结果、分化机制、应用前景及需解决的问题等进行了综述。     

确保县级农机成人教育健康稳定发展的几点思考

本文结合陕西省洛南县及周边县(区)农机成人教育情况，分析农机成人教育健康发展的新模式，供同行们探讨、思考。     

绵羊寄生线虫在体内及牧场上各发育阶段的季节动态研究

对亚热带草地模式区──湖北长阳火烧坪草畜示范场绵羊寄生线虫的优势种捻转血矛线虫、环纹奥斯特线虫和粗纹食道口线虫进行了成虫寄生量、羊粪中虫卵排出量和寄生虫体外发育育成率的逐月观察，结合气象资料──气温、相对湿度、蒸发量和雨量的观察记录，得出了这些优势种各发育阶段在绵羊体内及牧地上的季节动态以及与气温、湿度变化的关系。３种线虫在牧地上的体外育成率和在羊体内的寄生量都有２个峰，育成率于４月出现第１个峰，随之在５月成虫出现第１个峰，育成率于６或７月分别出现第２个更高的峰，成虫也于７～９月出现第２个更高的峰。说明成虫峰随体外发育育成峰而来，粪中虫卵的峰值则往往跟随成虫峰而出现。体外育成率的高低又明显受气温及温度影响，平均湿度低于１２℃时无峰出现，低于５℃时育成率为零，湿度在７９％以下时育成率很低。本文还讨论了防制建议。