Expression of CENH3 alleles in synthesized allopolyploid Oryza species

Synthesized allopolyploids are valuable materials for comparative analyses of two or more distinct genomes,such as the expression changes(activation,inactivation or differential expression)of orthologous genes following allopolyploidization.CENH3 is a centromerespecific histone H3 variant and has been regarded as a central component in kinetochore formation and centromere function.In this study,interspecific hybrids of Oryza genus(AA × CC,AA × CCDD)and their backcross progenies were produced,and the genome constitutions were identified as AC,ACC,ACD,AACD,or AA(CD)by Genomic in situ hybridization(GISH).We further cloned and sequenced the CENH3 genes from O.sativa(AA),O.officinalis(CC)and O.latifolia(CCDD).Sequencing of RT-PCR products revealed that CENH3_C2 and CENH3_D,the two CENH3 alleles from O.latifolia,showed polymophism in several sites,while CENH3_C2 and CENH3_C1 from O.officinalis were different at only two amino acids positions.Moreover,we found that the CENH3 genes from both parents are expressed in interspecific hybrids and their progenies.Specifically,based on our cDNA sequencing data,the ratio of expression level between CENH3_A and CENH3_C1 was approximately 1 in AC and 0.5 in ACC genomes,respectively.As a result,the CENH3 expression patterns shed more light on the inter-coordination between varied centromeric DNA sequences and highly conserved kinetochore protein in synthesized allopolyploids of Oryza genus.     

标记辅助选择改良数量性状的研究进展

本文系统地介绍了近年来有关标记辅助选择改良数量性状的研究进展,主要包括标记辅助回交、指数选择与最佳线性无偏预测的理论和应用研究概况.理论与计算机模拟表明标记辅助选择比常规表型选择更有效,但在实际育种中并不理想.同时本文还就当前标记辅助选择存在的问题和前景进行了讨论。 Abstract:Recent advances on marker-assisted selection (MAS) in the improvement of quantitative traits are reviewed.These include theoretical researches and applications of marker-assisted backcrossing,index selection,and best linear unbiased prediction (BLUP) in animal and plant breeding.Theoretical and simulation studies show that marker-assisted selection can substantially increase the efficiency of selection in comparison to phenotypic selection,but is not yet a proven technology.Problems and prospects in MAS are also discussed.     

标记辅助选择改良数量性状的研究进展

本系统地介绍了近年来有关标记辅助选择改良数量性状的研究进展,主要包括标记辅助回交、指数选择与最佳线性无偏预测的理论和应用研究概况。理论与计算机模拟表明标记辅助选择比常规表型选择更有效,但在实际育种中并不理想。同时本还就当前标记辅助选择存在的问题和前景进行了讨论。     

中山杉302回交一代的早期选育

连续3年对中山杉302(Taxodium'Zhongshansha302')回交一代(BackcrossedF1,简称为BCF1)〔中山杉302(T.'Zhongshansha302')×墨杉(T.mucronutumTenore)〕的13个无性系的苗期生长量(株高和地径)、标准木的地上部分生物量和分枝结构进行了测定,结果表明:BCF1102、BCF1118、BCF161和BCF1149的生长量和地上部分生物量明显高于亲本中山杉302,可以作为优选出的4个具有潜在推广价值的新无性系:其中BCF1102、BCF1118和BCF1613个无性系树干生物量占地上部分总生物量的比例均大于50%,也高于其他无性系,而树枝生物量比例较低,可以作为速生用材类型,BCF1149树叶生物量占地上部分总生物量的比重高达45%,可以作为速生观赏类型。运用通径分析方法对标准木的分枝结构与树高生长量的关系进行了分析,结果表明分枝数量是树高生长的首要决定因素,这4个速生无性系单株分枝数量高于其他类型。盐碱地造林结果表明:在pH8.5的滨海轻盐上,除BCF161的生长量受到一定抑制外,其他3个无性系BCF1102、BCF1118和BCF1149的生长量仍高于亲本中山杉302。运用RAPD分子标记鉴定了这4个优良无性系的遗传身份。     

中国春phlb突变体与多倍体Aegilops杂种F1回交植株（BC1F1）的细胞学研究

中国春phlb突变体与5个多倍体Aegilops的杂种F1用普通小麦进行回交,并对回交一代（BC1F1）的细胞学进行了研究。结果表明,BC1F1植株花粉母细胞最高染色体数56条,最低35条,一般情况下phlb基因可以增加BC1F1植株的染色体数（不是所有组合）,但不能增加染色体配对水平。杂种F1回交时有效雌配子最高染色体数在含有phlb基因组合中高于不含phlb基因的组合,但最低不杂色体数目相等,且含有21条染色体雌配子最具有竞争力,同时也证明,回交的成功并不取决于杂种F1通过重建分裂（restitution division)形成的未减数雌配子。     

十和田/丽粳2号回交重组自交系糙米Zn含量与其他元素和农艺性状间相关性

用ICP-AES法测定了十和田/丽粳2号/十和田BC4F5回交重组自交系264个株系糙米Zn含量及其在株型间的遗传变异,分析了糙米Zn含量与16种元素(K、P、S、Mg、Ca、Mo、Ni、Fe、Cr、Na、Al、Cu、Sn、B、Mn和Sr)、9个农艺性状(结实率、实粒数、秕粒数、穗长、有效穗、花药长度、花药宽度、穗茎节间长和倒2叶长)、MDA(丙二醛)含量、3种酶(POD、SOD、CAT)活性间相关性,旨在揭示糙米Zn与其他元素、稻米产量、稻耐冷性等关联性。结果表明:回交重组自交群体糙米Zn含量为正态分布,有超亲优势株系;糙米Zn含量与8种元素(K、S、P、Mg、Ca、Fe、B、Mn)含量呈极显著相关,与5种元素(S、Mg、Ni、Cr、Al)含量呈显著偏相关;初步认为糙米Zn含量与稻米产量及耐冷性为负相关,与酶活性相关性不显著。