梨种质资源遗传多样性研究中的AFLP技术引物筛选

本研究对带有3个选择性核苷酸的EcoRI和MseI引物各8个所组成的64个引物组合进行筛选,选出了多态性高的引物10对用于正式扩增。所选出的引物组合共扩增出371个位点,其中多态性位点306个,占总位点数的82.5%,每个引物组合扩增的位点数变化在23-55个之间,平均37.1个。所筛选出的10个引物组合为梨属植物AFLP扩增多态性引物,可广泛用于梨属植物的AFLP扩增技术。中国梨属植物资源丰富,通过对AFLP多态性引物的筛选,为该技术在梨属种质资源中的应用提供参考。     

不同类型黄瓜亲缘关系的AFLP分析

用AFLP分子标记对4种不同类型黄瓜种质资源进行了多态性分析.利用NTSYS软件分析遗传相似系数,UPGMA方法聚类,构建亲缘关系系统图.从50对AFLP引物中筛选出24对多态性高、扩增稳定、重复性好的引物.结果表明:24对引物组合共产生1 367条扩增带,平均每对引物组合产生56.96条;共产生多态性位点297个,多态性比率为21.7%.28份材料两两间的遗传相似系数在0.841 3～O.994 9之间.聚类分析结果显示,28份材料被聚成7小组,各组内生态类型基本一致.其中,华北有刺类型黄瓜在DNA水平上的同源性极高,遗传变异度较小,多样性水平较低,不如其他3个类型黄瓜多样性丰富.试验结果表明AFLP标记位点多,重复性好,可以揭示不同类型黄瓜种质之间的遗传基础.     

石榴基因组DNA的提取及RAPD引物筛选

以山东省枣庄市峄城区中国石榴种质资源圃内石榴品种为材料,采取改良CTAB法提取石榴基因组DNA,经RAPD-PCR扩增筛选引物。结果表明：CTAB法提取的石榴基因组DNA谱带清晰,纯度高,浓度大,可以用于RAPD分析。从50条随机引物中筛选出多态性高、重复性好的多态性引物20条。20条引物对10个品种扩增结果共产生180个位点,多态性位点为134,多态性比率为74.4%。     

大白菜的适宜AFLP-Pst I/Mse I引物组合

基于PCR的DNA指纹鉴定技术AFLP广泛应用于生物多样性、遗传图谱构建、基因定位、分子系统发育和品种鉴定等方面.为了筛选出大白菜适宜的AFLP引物组合,研究以抗根肿病大白菜双单倍体CR Shinki、感病自交系94SK及其后代F2构成的纯合抗病和纯合感病DNA混合池为材料,利用256对Pst I/Mse I引物组合进行了AFLP分析.结果表明:平均每个组合检测到55条带,共扩增13 079条带,平均每1 000条带检测到1.30个根肿病抗性基因连锁标记;多态性带数为3 167条,双亲间多态性频率约为0.24;扩增带数与多态性带数呈线性正相关,引物组合中的不同GC含量与扩增带数和多态性带数存在显著性差异,并表现出线性负相关.筛选出的适宜53对引物组合共扩增出4 381条带,占总扩增片断的33.50%,平均每对扩增出83条,其中9个组合扩增出与抗根肿病基因连锁标记.     

7种SH系苹果砧木的AFLP分析

以7种SH系苹果砧木叶片为材料，利用改良的CTAB(溴代十六烷基三甲胺)法提取DNA，通过AFLP-银染体系，对SH系砧木进行了DNA多态性和遗传多样性分析。从随机组合的143对“3+3”引物中筛选出20对引物应用于扩增基因组DNA，共获得548条清晰可辨的扩增带，其中261为多态性条带，多态率为47%。依据简单匹配系数对AFLP扩增结果进行UPGMA聚类，7种SH系砧木在0.58水平上分为2个大类群。     

应用AFLP技术检测莲藕遗传多样性的初步研究

利用AFLP技术对12个莲藕品种进行了DNA多态性分析。从10对引物中筛选出2对引物应用于扩增基因组DNA,共获得72条带,其中64条为多态性标记,每个引物平均提供36个标记信息。由UPMGA方法进行聚类分析结果显示了12个品种间的亲缘关系,聚类结果与它们的系谱关系非常吻合。     

AFLP在水稻类群划分研究中的应用

利用AFLP分子标记技术研究了22个水稻品种的遗传多样性，从49对AFLP引物中筛选出了4对多态性高，分辨能力强的引物，4个AFLP引物组合分别扩增出43、37、49、33条多态性带，平均每个引物组合扩出40．5条多态性带，4个引物组合共扩增出246条带。利用AFLP数据进行聚类分析，将22个品种聚为8群，结果表明，AFLP在水稻类群划分的应用是可行的。     

高粱AFLP分子连锁图谱的构建

利用感蚜高粱品种千三与抗蚜品种河农16杂交获得的100个F2单株作为图谱构建群体,以AFLP标记构建高粱连锁图谱。通过对192对AFLP引物组合进行筛选,共得到75对多态性引物,利用筛选出的75对引物进行选择性扩增,得到了154个AFLP多态性位点。经Map maker/EXP 3.0软件处理,构建了包含12个连锁群,93个遗传标记的连锁图谱,该图谱覆盖686 cM,平均图距为7.38 cM。     

辣椒细胞质雄性不育基因的AFLP分析

本文采用AFLP(amplified fragment length polymorphism)技术对辣椒(Capsicum annuum L.)细胞质雄性不育系21A及其相应的保持系21B基因组DNA进行多态性比较,筛选了64对AFLP选择性引物PstⅠ-NNN+Mse Ⅰ-NNN组合,有60对引物组合均在两系间扩增出5 447条带,多态性位点为4个,其中在不育系材料中仅有2个多态性片段AGC/CGC378和ATC/GAG446,对特异片段进行克隆、测序,其序列全长分别为340 bp和408 bp,它们编码的氨基酸序列与烟草基因组线粒体DNA序列同源性达94%和96%.     

甘蔗（Saccharum officinarum L.）品种遗传差异的AFLP分子标记分析

采用AFLP技术,从64对引物中筛选出5对带型分布均匀、多态性丰富且分辨能力强的引物,对两个在生产上广泛推广应用的甘蔗品种的AFLP指纹图谱进行分析,计算了两品种间的遗传相似性和遗传距离。结果表明,5对引物在2个甘蔗品种间均存在显著的差异,其中多态性位点占总扩增位点的10.2%,区分率达100%。这对应用AFLP技术鉴定甘蔗     

Cytology of Phleum sp. affin. P. montanum C. Koch

Diploid, tetraploid, and hexaploid plants occurred in foreign plant introductions of P. sp. affin. P. montanum from Turkey and Iran. Within-progeny variations in polyploid levels indicate that divergent races occurred as interspersed but natural populations. One to six B-chromosomes of varying sizes in addition to the normal chromosome complement were present in some plants. Their behaviours appeared essentially similar to those recorded for other species. Certain of the plants examined exhibited cytological features similar to those observed in known hybrids. These included prophase pycnosis, stickiness, split metaphase I plates, unoriented chromosomes at M-1, and low levels of pollen stainability. These features were absent in microsporocytes of other plants. Low open-pollination seed set characterized all plants examined. This may be due to hybridity or possibly to response to ecological conditions of the new environment.Results of co-operative work of the Crops Research Division, A.R.S., U.S. Department of Agriculture, and the Wisconsin Agricultural Experiment Station, Madison, Wisconsin.Former Graduate Student, Department of Agronomy, Wisconsin Agricultural Experiment Station, and Geneticist, Crops Research Division, Agricultural Research Service, U.S. Department of Agriculture.     

U.S. Economic Growth vs. Environmental Conditions

A widely-held belief is that stricter environmental regulations stifle economic growth. To determine empirically the effect of environmental conditions and policies on state-level per capita income growth, a Barro-type economic growth model was estimated for the years 1982 to 1991, which correspond to two consecutive troughs in the business cycle. States with better environmental conditions had significantly higher income growth rates during this period. At the same time, stricter environmental policies did not significantly depress income growth. Data used include recently developed, consistent measures of environmental policy and quality for individual states, as well as data from the 1980 U.S. Census and Bureau of Economic Analysis.