Further molecular evidence for the Hordeum vulgare ssp. spontaneum in Tibet as ultimate progenitor of Chinese cultivated barley

106 aeeessions of Tibetan wild barley, including 50 accessions of the two-rowed wiht barley Hordeum vulgare ssp. sopntaneum （HS）, 27 accessions of the six-rowed bottle-shaped wild barley H. lagunculiforme （HL） and 29 accessions of the six-rowed wiht barley H. agriocrithon （HA） that separately represent different agrigeographical regions of Tibet, were used to study the genetic diversity and genetie differentiation using SSR markers selected from seven barley linkage groups. 229 allelic variants were identified with an average of 7.6 alleles/locus. The average of total number of alleles per locus in HA （6.4） is much higher than that in HS （3.9） and HL （3.4）. The genetie diversity and its standard deviation among the three subspecies were in the order of HS〉HL〉HA. Very significant genetic differentiation was observed among the three subspecies of wild barley. Comparisons of the results fiom this and previous studies showed a strong Oriental-Occidental differentiation of barley, and that Shannan region of Tibet might be the center of origin of the Tibetan two-rowed wild barley, thus supporting not only the hypothesis of a mono-phyletie origin of cultivated barley but also the proposition that the Tibetan two-rowed wild barley as ultimate progenitor of Chinese cultivated barley.     

小麦taf1位点的连锁不平衡分析

利用遍布全基因组的21个SSR分子标记,对小麦雌性不育系XND126与1201、802、60个普通小麦品种(系)组成的三个品种(系)群体进行群体结构的评估,发现在三个群体中都存在群体结构.对消除群体结构后的三个亚群体中各标记的连锁不平衡值(linkage disequilibrium value)进行比较.结果表明,群体大小影响标记与雌性育性位点间的LD值.基于对小麦雌性育性taf1位点初步定位的信息.对2DS染色体上30个SSR分子标记的LD研究显示,Xgwm71、Xwmc25、Xgwm515、Xcfd36同样与原标记Xgdm35等具有较大的LD值,可能与taf1密切相关.获得这些较大LD值的标记(Xgwm71、Xwmc25等),为taf1位点的精细定位做出了充分的准备.     

吉林省主推中晚熟期玉米品种DNA指纹库的构建

以吉林省中晚熟期的43个玉米品种为材料, 从玉米胚中提取基因组DNA并利用10对简单重复序列(SSR)引物进行扩增, 扩增产物经质量分数为8%的聚丙烯凝胶电泳检测, 获得了清晰稳定的图谱, 初步建立了吉林省中晚熟期玉米43个品种的DNA指纹库.     

小麦染色体2DS雌性育性位点遗传多态性分析

小麦雌性不育系XND126属于生态遗传型不育系.通过SSR分子标记分析,在2DS染色体上定位了一个雌性育性主效QTL位点.为了构建高密度遗传图谱并精细定位该主效位点,用2DS参考遗传图谱上的14对SSR标记,研究了59个育性正常的普通小麦品种与XND126的DNA多态性,筛选到不同生态型多态性较高的品种共12个,每个品种多态性标记达12~13个,这些品种可以用作杂交亲本,构建新的QTL精细定位群体.在品种组成的群体中,与主效基因位点最近的标记,表现出有较多的品种与雌性不育系具有差异.     

Genetic diversity and construction of core collection in Chinese wheat genetic resources

Genetic diversity among 5029 accessions representing a proposed Chinese wheat core collection was analyzed using 78 pairs of fluorescent microsatellite （SSR） primers mapped to 21 chromosomes. A stepwise hierarchical sampling strategy with priority based on 4×10^5 SSR data-points was used to construct a core collection from the 23090 initial collections. The core collection consisted of 1160 accessions, including 762 landraces, 348 modern varieties and 50 introduced varieties. The core accounts for 23.1% of the 5029 candidate core accessions and 5% of the 23090 initial collections, but retains 94.9% of alleles from the candidate collections and captures 91.5% of the genetic variation in the initial collections. These data indicate that it is possible to maintain genetic diversity in a core collection while retaining fewer accessions than the accepted standard, i.e., 10% of the initial collections captured more than 70% of their genetic diversity. Estimated genetic representation of the core constructed by preferred sampling （91.5%） is much higher than that by random sampling （79.8%）. Both mean genetic richness and genetic diversity indices of the landraces were higher than those of the modern varieties in the core. Structure and principal coordinate analysis revealed that the landraces and the modern varieties were two relatively independent subpopulaUons. Strong genetic differentiation associated with ecological environments has occurred in the landraces, but was relatively weak in the modern culUvars. In addition, a mini-core collection was constructed, which consisted of 231 accessions with an estimated 70% representation of the genetic variation from the initial collections. The mini-core has been distributed to various research and breeding institutes for detailed phenotyping and breeding of genetic introgression lines.     

贵州西山系列玉米杂交种SSR标记纯度鉴定的研究

以11个贵州西山系列玉米杂交种及相应的15个亲本自交系为材料,采用SSR（Simple Sequence Repeat）分子标记方法,从60对多态性高的引物中分别筛选了双亲互补型特异引物,并利用特异引物进行玉米杂交种纯度鉴定的检验．     

DNA分子标记的发展及主要技术

DNA分子标记技术是一种新的比较理想的遗传标记,本文综述了DNA分子标记技术的发展概况、种类及特点,以及广泛应用于农作物分子标记基因定位的分子标记技术：限制性片段长度多态性（RFLP）,随机扩增多态性DNA（RAPD）,简单序列长度多态性标记（SSR）和扩增的限制性内切酶片段长度多态性（AFLP）的原理、特点及他们的优缺点。     

豇豆SSR标记在豌豆中的可转移性与应用初探

利用豇豆SSR引物筛选在豌豆具通用性的SSR引物。13对豇豆SSR引物中检测出8对引物在豌豆中可扩增,其中5对SSR引物表现出多态性,进而分析11个豌豆品种和5个豇豆品种的遗传多样性与遗传关系。结果表明:平均等位基因数、平均有效等位基因数、平均Shannon指数,在豌豆品种群中分别为2.00、1.64、0.55,豇豆品种群中分别为2.00、1.80、0.53,上述遗传参数反映出供试豌豆品种和豇豆品种具有中等水平的遗传多样性;利用UPGMA聚类分析,能将豌豆品种群和豇豆品种群分为两类,且每个品种群内的各个体之间能进行区分,尤其是两个豌豆品种亚群的聚类结果与其地理来源基本一致。     

四个不同来源途径玉米自交系的DNA指纹分析

利用SSR分子标记技术,对不同来源的四个玉米自交系65232、Mo17、P138、917进行DNA指纹检测.检测了75对引物,其中Bnlg1439、Bnlg197、Phi126等8对在谱带位置或数量上已出现差异.分析表明,自交系在使用过程中已发生分化或遗传漂移,在自交系提纯复壮中可以利用这8个标记进行辅助选择育种.     

粗山羊草Y189抗小麦白粉病基因SSR标记

从粗山羊草[Aegilops tauschii(Coss.)Schmal]Y189中鉴定出1个显性抗小麦白粉病基因,暂定名为PmAe Y2.应用分离群体分组法(BSA)筛选到Xgwm583-5D、Xgwm174-5D、Xgwm182-5D和Xgwm271-5D标记与该基因之间的遗传距离分别为25.7、16.7、9.1和7.0 cM.根据连锁标记所在小麦微卫星图谱的位置,PmAe Y2被定位在5DL染色体上.分析基因所在染色体的位置、抗病性特征认为PmAe Y2是一个新的抗白粉病基因,并可用于分子标记辅助选择.