ISSR-Based Molecular Characterization of an Elite Germplasm Collection of Sweet Potato （Ipomoea batatas L.） in China

To determine the genetic diversity and population structure of sweet potato accessions cultivated in China, and to establish the genetic relationships among their germplasm types, a representative collection of 240 accessions was analyzed using inter-simple sequence repeat （ISSR） markers. The mean genetic similarity coefifcient, Nei’s gene diversity, and shared allele distance of tested sweet potato accessions were 0.7302, 0.3167 and 0.2698, respectively. The 240 accessions could be divided into six subgroups and ifve subpopulations based on neighbor-joining （NJ） clustering and STRUCTURE results, and obvious genetic relationships among the tested sweet potato accessions were identiifed. The marker-based NJ clustering and population structure showed no distinct assignment pattern corresponding to lfesh color or geographical ecotype of the tested sweet potato germplasm. Analysis of molecular variance （AMOVA） revealed small but signiifcant difference between white and orange-lfeshed sweet potato accessions. Small but signiifcant difference were also observed among sweet potato accessions from the Southern summer-autumn sweet potato region, the Yellow River Basin spring and summer sweet potato region and the Yangtze River Basin summer sweet potato region. This study demonstrates that genetic diversity in the tested sweet potato germplasm collection in China is lower than that in some reported sweet potato germplasm collections from other regions. Pedigree investigations suggest that more diverse Chinese sweet potato varieties should be formed by broadening the selection scope of breeding parents and incorporating the introduced varieties into future breeding programs.     

Molecular Mapping of a Stripe Rust Resistance Gene YrH9020a Transferred from Psathyrostachys huashanica Keng on Wheat Chromosome 6D

Stripe rust （yellow rust）, caused by Puccinia striiformis f. sp. tritici （Pst）, is one of the most devastating diseases of wheat throughout the world. H9020-1-6-8-3 is a translocation line originally developed from interspeciifc hybridization between wheat line 7182 and Psathyrostachys huashanica Keng and is resistant to most Pst races in China. To identify the resistance gene（s） in the translocation line, H9020-1-6-8-3 was crossed with susceptible cultivar Mingxian 169, and seedlings of the parents, F1, F2, F3, and BC1 generations were tested with prevalent Chinese Pst race CYR32 under controlled greenhouse conditions. The results indicated that there is a single dominant gene, temporarily designated as YrH9020a, conferring resistance to CYR32. The resistance gene was mapped by the F2 population from Mingxian 169/H9020-1-6-8-3. It was linked to six microsatellite markers, including Xbarc196, Xbarc202, Xbarc96, Xgpw4372, Xbarc21, and Xgdm141, lfanked by Xbarc96 and Xbarc202 with at 4.5 and 8.3 cM, respectively. Based on the chromosomal locations of these markers and the test of Chinese Spring （CS） nullitetrasomic and ditelosomic lines, the gene was assigned to chromosome 6D. According to the origin and the chromosomal location, YrH9020a might be a new resistance gene to stripe rust. The lfanking markers linked to YrH9020a could be useful for marker-assisted selection in breeding programs.     

道地产区不同牛膝种群的遗传多样性分析

【目的】对道地产区河南8个野生牛膝种群叶绿体基因psbA-trnH序列的变化进行分析,研究牛膝种群的遗传多样性,为牛膝野生种群的保护提供依据。【方法】选取河南8个野生牛膝种群(信阳鸡公山种群、信阳灵山种群、南阳淮源种群、南阳大乘山种群、洛阳龙峪湾种群、南阳老界岭种群、新乡九莲山种群、新乡万仙山种群)为材料,PCR扩增其叶绿体多态性片段psbA-trnH,分析其在供试8个牛膝野生种群中的差异,并据此分析各种群的遗传多样性。【结果】从8个牛膝种群的叶绿体片段中得到6个单倍型(Ⅰ~Ⅵ),其中单倍型Ⅰ为祖先单倍型,与其他单倍型仅差1个突变步。牛膝单倍型多样性指数为0.594,核苷酸多样性指数为2.13×10-3。牛膝种群遗传距离与地理距离之间不存在正相关关系。淮源种群的遗传多样性最高,且有特殊的基因型Ⅱ和Ⅴ;九莲山种群具有特殊的基因型Ⅵ。【结论】道地产区河南野生牛膝种群的遗传多样性相对较低;淮源种群与九莲山种群应该作为保护单元受到更多的重视。     

分子生物学教学改革探究

针对六盘水师范学院分子生物学教学存在的问题,结合教学实践,从理论课教学改革和实验课教学改革两方面对该课程进行了阐述,以期在今后分子生物学课程的教学过程中取得更好的效果。     

转基因技术在玉米育种中的运用

就玉米转基因在抗除草剂、抗虫、抗病、抗盐碱等方面取得的成果进行了回顾,以期为我国玉米分子育种研究提供参考。     

稻飞虱翅型分化的研究进展

翅二型现象存在于褐飞虱(Nilaparvata lugens)、灰飞虱(Laodelphax striatellus)和白背飞虱(Sogatella furcifera)等稻飞虱种群中.综述了遗传等内在因素以及外部因素(温度、相对湿度、光周期、寄主等)对3种稻飞虱长、短翅型分化的影响,探讨了各因素对稻飞虱翅型分化的作用机制,讨论了稻飞虱翅型分化研究中存在的问题,并对制定与稻飞虱翅型分化相关的害虫控制策略提出了建议.     

植物高温抗性转录因子基因工程研究进展

高温胁迫是影响植物生长代谢和产量的重要因素之一,通过基因工程方法能提高植物抵御热胁迫的能力。现对近年来发现的与植物高温抗性有关的转录因子进行综述,并阐述了通过基因工程方法利用已知转录因子提高植物抗热性的研究进展,以期为利用基因工程方法培育抗热植物提供参考。     

樟子松引种驯化和遗传改良研究现状

樟子松为中国北方特有的珍贵树种,具有生长快、适应性、耐干旱瘠薄的优良特性,经济、社会和生态价值显著。因此,樟子松这一珍贵资源的引种驯化与遗传改良极为重要,在汲取国内外相关研究成果和学术观点的基础上,系统阐述了樟子松的种源试验、引种驯化、遗传改良、良种选育、种质保存及可持续利用等领域的研究现状和进展,指出了种质资源保存方面存在的不足,展望了种质资源可持续经营的广阔前景,提出了优异种质创新利用的具体思路和对策,以期为拯救并保护障子松资源提供理论参考。     

新疆额尔齐斯河流域苦杨与欧洲黑杨遗传多样性分析

应用SSR标记技术,对新疆额尔齐斯河流域河谷分布的苦杨(Populus laurifoli)和欧洲黑杨(Populus nigra)天然居群的遗传多样性和遗传分化进行了研究。结果显示:苦杨和欧洲黑杨的天然居群具有较高的遗传多样性,且苦杨明显高于欧洲黑杨。与苦杨居群相比,欧洲黑杨居群间基因流较高,居群间的遗传分化程度较小,变异主要源于居群内。苦杨和欧洲黑杨居群内的杂合度较高,各个居群的各项遗传参数都要小于物种水平。苦杨和欧洲黑杨均偏离Hardy-Weinberg平衡,表现为杂合子过量的现象。     

101份糯玉米自交系的遗传多样性

为筛选出形态学表现好、遗传距离较远的糯玉米自交系类群,利用 SSR分子标记技术对表型不同的101份糯玉米自交系进行 SSR 分子标记遗传多样性分析。结果表明,30对 SSR 引物筛选出23对多态性好、带型稳定的引物,分布在玉米所有染色体上;共检测出128个条带,108个等位基因,平均每个引物检测出4．7个等位基因;23对引物多态性信息量为0．59～0．94,平均为0．85;SSR 聚类结果将101份糯玉米自交系分为10大类群。