不结球白菜杂种优势及相关分析

以4个不结球白菜不育系与4个父本系以NCⅡ法配制16个杂交组合,研究了16个F1组合的杂种优势表现及其与亲本之间的相关关系,同时对性状间的遗传相关进行分析.结果表明:不结球白菜产量性状杂种优势＞农艺性状杂种优势＞光合性状杂种优势＞品质性状杂种优势.产量性状以超亲优势为主,农艺性状和光合性状以中亲优势为主,品质性状中可溶性糖含量以中亲优势为主, Vc含量和蛋白质含量均为弱的负向优势.亲子相关分析表明,一些性状F1与中亲值、低亲值或高亲值显著相关,因此在亲本选配时,注意亲本差异的同时,中亲值特别是低亲值不能过低,尤其是品质性状.性状间相关分析显示,光合性状与产量性状显著正相关,说明F1高效的光合同化作用是杂种高产的基础.品质性状中,可溶性糖含量与产量显著正相关,但Vc和蛋白质含量与产量负相关,在亲本选配时还应注意二者的协调.     

杂交稻特殊配合力与杂种优势、亲本间遗传距离的相 关性

杂交水稻育种的实质是配合力育种, 筛选高特殊配合力的杂交水稻组合才能选育出在生产上有实用价值的强优势组合。文章利用SSR标记检测了9个三系杂交稻亲本(5个不育系和4个恢复系)之间的遗传距离, 结合20个杂交稻组合(5×4 NCII)的产量表现, 分析了杂交水稻特殊配合力(Special combining ability, SCA)效应与产量杂种优势、亲本间遗传距离的相关性。结果表明, 特殊配合力效应与对照优势(相关系数r₁=0.5609)、平均优势(相关系数_r2=0.541)之间均呈显著正相关, 而与亲本遗传距离之间相关不显著, 相关系数(r=0.2143)较小。说明本研究所配组合的特殊配合力效应能充分反映杂种优势, 选用的杂交亲本能组配出强优势组合; 而杂交亲本遗传距离的大小并不能反映特殊配合力效应, 分子标记遗传距离与特殊配合力的相关性还有待于进一步的探讨。     

不同松树种间杂交类型的可育性分析

探究不同松树种间杂交可育性,为松树种间杂交育种亲本选配提供依据,进而为松树的杂种优势研究积累材料.该研究利用随机区组设计,通过92个松树种间杂交组合与20个半同胞对照,分析9种松树种间杂交类型子代的平均球果产种数、平均球果产种量、百粒重、发芽率与成苗率5项育性指标,综合球果期、种期与苗期3个阶段的表现,利用模糊数学隶属...     

标准切花菊杂交F1代群体侧枝侧蕾性状的杂种优势和遗传分析

以标准切花菊〔Dendranthema morifolium(Ramat.)Tzvel.〕品种'优香'('Yuuka')为母本、品种'神马'('Jinba')为父本进行杂交,对杂交F1代群体的单株侧枝平均长度、单株侧枝数、单株侧枝数与单株叶节数的比值(R1)、主蕾直径与侧蕾直径的比值(R2)、单株侧蕾数以及主蕾与侧蕾间距离6个性状进行杂种优势和相关性分析,并利用主基因+多基因混合遗传模型检测这些性状的主基因效应.结果显示:杂交F1代群体6个侧枝侧蕾性状的变异系数为2378%~5065%,且侧枝性状的变异系数总体上高于侧蕾性状;各性状的频次均呈现连续性的正态分布趋势,说明这些性状可能属于多基因控制的数量性状.杂交F1代群体的6个侧枝侧蕾性状均在001水平上表现出显著的中亲优势,表明各性状均存在显著的杂种优势.6个性状中,单株侧枝平均长度的中亲值最大(6230 mm),R1的中亲值最小(026);单株侧枝平均长度、R2和主蕾与侧蕾间距离的中亲优势均为正值,单株侧枝数、单株侧蕾数和R1的中亲优势均为负值.6个性状的中亲优势率为-5374%~3128%,其中,单株侧枝数的中亲优势率最小,而主蕾与侧蕾间距离的中亲优势率最大.相关性分析结果显示:单株侧枝平均长度和单株侧枝数均与R1呈极显著正相关,并与R2和单株侧蕾数呈极显著负相关;R2与侧蕾数也呈极显著正相关,且二者均与主蕾与侧蕾间距离呈极显著正相关.混合遗传分析结果显示:单株侧枝平均长度、R1、R2和单株侧蕾数均受2对主基因控制,符合B-1模型,主基因表现为"加性-显性-上位性",这4个性状的遗传率分别为7707%、9672%、6438%和5307%;单株侧枝数也受2对主基因控制,符合B-2模型,主基因表现为"加性-显性",该性状的遗传率为7438%,表明这5个性状的遗传存在主基因控制效应.而主蕾与侧蕾间距离符合A-0遗传模型,说明该性状无主基因控制,易受环境影响.     

6个烟草杂交组合花药再生苗的培养和DH群体的构建

以6个烟草(Nicotiana tabacum L.)杂交组合的花药为实验材料,对各杂交组合花药再生苗出苗状况及培养过程中添加H液体基本培养基对花药出苗状况的影响进行了比较分析;在此基础上,采用质量体积分数0.4%秋水仙素浸苗法构建加倍单倍体(DH)群体,对加倍处理后不同杂交组合再生苗的成苗率、大田移栽成活率及染色体加倍率等进行分析,并对杂交组合DH1单倍体和加倍单倍体植株叶片气孔保卫细胞叶绿体数的差异进行了研究。结果表明:不同杂交组合每枚花药的出苗数、加倍处理后再生苗的成苗率、大田移栽成活率及染色体加倍率有较大差异。其中,每枚花药出苗数为1.57～3.30,杂交组合DH5每枚花药的出苗数最多,达到3.30株,显著高于其他5个杂交组合(P<0.05);加倍处理后再生苗的成苗率为21.12%～33.42%,大田移栽成活率为91.87%～98.86%,杂交组合DH6的成苗率和大田移栽成活率最高;染色体加倍率为6.64%～10.78%,杂交组合DH4的染色体加倍率最高。花药培养约15 d后,添加H液体基本培养基能够显著促进杂交组合DH1和DH2花药出苗。杂交组合DH1单倍体苗和加倍单倍体苗叶片气孔保卫细胞的平均叶绿体数分别为9.27和17.46,二者比值接近1∶2,差异显著。通过花药培养和染色体加倍处理,分别获得了6个烟草杂交组合的DH群体。     

杂交水稻幼芽呼吸和抗氰呼吸强度的研究

本文研究了13个水稻杂交组合幼芽总呼吸强度和抗氰呼吸强度,发现杂交水稻幼芽总呼吸和抗氰呼吸强度多表现为负优势。杂种幼芽总呼吸强度及抗氰呼吸强度与其亲本均值均呈极显著正相关,回归关系亦极显著。杂种幼芽抗氰呼吸和其中亲值的差值与其父母本之差值呈显著正相关,而杂种幼芽呼吸强度其中亲值的差值与其父母本之差值呈不显著负相关。认为杂种幼芽的抗氰呼吸强度和总呼吸强度均可由其双亲均值预测,抗氰呼吸强度作为杂种优势预测生理指标的潜力更大一些。     

粳稻杂交一代及其亲本的硝酸还原酶活力

木文以水稻4个杂交组合一代及其相应的亲本为材料,观察了杂交一代及其亲本的硝酸还原酶活 力之间的关系。结果表明,杂交一代硝酸还原酶活力高低与其亲本硝酸还原酶活力高低有密切相关。 即,亲本酶活力低与高或中与95的杂交一代酶活力同高亲,而中与中或低与中的杂交一代酶活力i于双 亲,表现一定的杂种优势。     

烤烟胞质雄性不育杂种经济性状的杂种优势表现

以自育的3个烤烟(Nicotiana tabacum L.)胞质雄性不育系和4个国内推广烤烟品种为材料,配成12个杂种,研究烤烟6个经济性状(产量、产值、均价、上等烟比例、上中等烟比例和级指)的杂种优势表现。结果表明:(1)经济性状的离中优势相当普遍,100%组合的产值和产量存在显著的正向离中优势,其它经济性状有12.50%-83.33%组合的离中优势达显著或极显著水平;(2)有较多组合的产量和上等烟比例存在超高亲优势,其中分别有75.00%和66.67%组合的超高亲优势达到显著或极显著水平,其它经济性状也有8.33%-50.00%组合的超高亲优势达到显著或极显著水平;(3)MsYZ203-6×红花大金元组合在6个经济性状上均表现极显著的超亲优势,MsYZ206-9×云烟87组合在除均价外的5个经济性状上表现极显著的超亲优势。     

栗属杂交F1代生长与枝条性状遗传变异及杂种优势分析

为探索栗属杂交F₁代幼林期生长、枝条性状遗传变异规律及杂种优势,并为栗属育种亲本选配及早期选择指标筛选奠定理论基础,该研究以锥栗、板栗种内和种间9个杂交组合子代及其亲本为材料,在分析F₁代幼林期生长、枝条性状遗传变异规律及杂种优势的基础上,利用SSR分子标记检测7个亲本的遗传距离,进而分析栗属杂交子代生长、枝条性状杂种优势与亲本遗传距离间的关系。结果显示：(1)栗属杂交F₁代生长、枝条性状均存在较高的遗传变异,各性状组合间F值的变动范围为5.08~22.03,组合内的变异系数范围为6.60%~27.69%;各性状广义遗传力均在0.5以上,性状受遗传影响较大;除地径外,其他性状遗传传递力均大于100%,性状遗传稳定性较高;各性状中亲优势率为-6.01%~44.40%,且F₁代生长、枝条性状存在普遍的超亲分离现象。(2)28对引物在7个亲本中共检测出115个多态性等位位点,每对引物的等位基因数3~5个不等,平均每对引物等位基因数为4.1个,多态性程度较高;Shannons 指数(I)、多态性信息含量(PIC)的平均值分别为1.25、0.674,亲本遗传多样性较为丰富。(3)相关分析表明,杂交子代一年生枝长、一年生枝粗及节间距的杂种优势与亲本遗传距离均存在显著的线性关系,并随遗传距离增大杂种优势增强。     

普通小麦与粗山羊草正,反交的育性研究

普通小麦与粗山羊草杂交需借助幼胚培养方可获得杂种,取授粉１２～１６天的幼胚进行拯拯救,成苗率较高,效果较好。而不同杂交方式对共杂种成胚率、成苗率及思胚拯救率影响很大。以普通小麦为母本,粗山羊草为父杂交时,１５个杂交组合平均杂种成胚率,成苗率及幼胚拯率分别为５．３５％和５８．７３％,而在１２个反交组合中,其平均成胚率,成苗率及幼胚拯救率分别为９８．８８％、１７．１０％和２４．４４％。由此可见,普通小     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.