Genetic basis of heterosis and inbreeding depression in rice （Oryza sativa L.）

The genetic basis of heterosis was studied through mid-parent, standard variety and better parent for 11 quantitative traits in 17 parental lines and their 10 selected hybrids in rice (Oryza sativa L.). The characters were plant height, days to flag leaf initiation, days to first panicle initiation, days to 100% flowering, panicle length, flag leaf length, days to maturity, number of fertile spikelet/panicle, number of effective tillers/hill, grain yield/10-hill, and 1000-grain weight. In general the hybrids performed significantly better than the respective parents. Significant heterosis was observed for most of the studied characters. Among the 10 hybrids, four hybrids viz., 17Ax45R, 25Ax37R, 27Ax39R, 31Ax47R, and 35Ax47R showed highest heterosis in 10-hill grain yield/10-hill. Inbreeding depression of F2 progeny was also studied for 11 characters of 10 hybrids. Both positive and negative inbreeding depression were found in many crosses for the studied characters, but none was found significant. Selection of good parents was found to be the most important for developing high yielding hybrid rice varieties.     

对棉花三系在配制杂种中应用价值的研究

将五个陆地棉恢复系和三个雄性不育系进行杂交，得到１５个杂种Ｆ１；并对杂种Ｆ１的重要农艺性状及纤维品质进行了研究．对试验数据的方差分析表明：有关铃重、衣分、纤维长度和整齐度方面杂种Ｆ１间的差异达到极显著的水平，而在皮棉产量、单株吐絮铃数上的差异却是不显著的．不育系中Ａ和ＰＡ在铃重、衣分和绒长上的一般配合力是高度显著的．恢复系４Ｒ—１６在铃重、衣分和纤维整齐度的一般配合力也都达到了极显著的水平．这些试验结果对以后的研究和选育强优杂种是有用的。     

Cloning of a down-regulated gene encoding small GTP binding protein in hybrid wheat

Previous studies showed that differential gene expression between wheathybrids and their parents was responsible for the heterosis. To provide an insight into the molecular basis of wheat heterosis, one cDNA, designated TaRab, was identified from the cDNA library of wheat seedling leaves. The sequence comparison in GenBank revealed that TaRab is homologous to a group of genes encoding Rab-GTP binding protein. Semi-quantitative RT-PCR analysis indicated that TaRab was expressed in all plant tissues examined, but at slightly higher level in leaves. Further analysis exhibited that TaRab displayed lower expression in hybrid than in its patents in both roots and leaves, which was in agreement with the original results of suppression subtractive hybridization. TaRab was located on chromosome 7B and C-7DS5-0.36 by in silico mapping. The relationship between differential expression of TaRab and the molecular basis of wheat heterosis was also discussed.     

Comparative growth and viability of hybrids between two populations of Chinese shrimp （Fennropenaeus chinensis）

The total yield of shrimp farming industry declined after WSSV broke out. It was only at the last 20 years that production had again begun to increase[1]. So far, shrimp farming industries mostly depend on capturing wild shrimps or wild post-larvae to sto…     

Comparative Studies on the Molecular Genetic Diversities among Haliotis discus hannai,H.discus discus and Their Hybrids

0　IntroductionAsagroupofthemostimportantmarineunivalvegastropods ,thegenusabalonehasmorethan 1 0speciescultivatedintheworldnowadays .However,themajorityofspeciesgrowslowly ,challengingtheircultivation .Manystudies ,includingtriploidizationofH .discushan nai (Zhang ,1 998) ,gynogenesisofH .discushannai(Fujino ,1 990 )andgrowthhormonegenetransformationofH .rufescens (Power,1 996 ) ,werecarriedouttowardthedevelopmentoffastgrowingvarieties .Unfortunately ,theseapproacheshavenotbroughtprofoundc…     

基于SLAF-seq玉米高密度遗传连锁图谱构建与株型性状QTL定位

 株型直接决定生物产量、种植密度与籽粒产量,利用玉米高密度遗传连锁图谱解析株型相关性状的遗传机制,对选育理想株型玉米新品种具有重要意义。本研究利用SLAF-seq技术,依据玉米黄早四参考基因组信息,对昌7-2与PHB1M及其138个F_2：3家系高通量测序,开发高密度SNP的遗传图谱,并进行株型相关性状QTL定位。研究结果构建了一张总图距为1354.81 cM,标记间的平均距离为0.32 cM,标记数为4220个SLAF标签（7876个SNP）的高密度遗传图谱。在E1与E2两种密度下,对株高、穗位、叶片数、节间数、平均节间长进行QTL定位,共检测到10个QTL位点,其中,有7个PVE超过了10%。叶片数、穗位、节间数为主效QTL,ADD为负值,叶片数与节间数的减效等位基因来源于PHB1M,穗位的减效等位基因来源于昌7-2。叶片数与节间数在2个密度下均定位在8号染色体上,说明二者之间有着共同的遗传机制。与QTL关联的SLAF标记共有61个,其中,SLFA7305498和SLFA6717271为qLC-2-LG8与qIC-2-LG8共有标记。该研究将为玉米株型相关性状的标记辅助选择提供支撑。     

陆地棉显性无腺体品系与常规品种间杂种优势利用研究 Ⅲ.杂种优势及其与配合力的相关

以７个显性无腺体陆地棉品系和４个常规品种为材料,按ＮＣⅡ设计,对２８个组合的Ｆ１杂种优势及其与配合力的相关进行了分析。结果表明：杂种Ｆ１具有明显优势,２８个组合所研究的１５个性状全部具有中亲优势,６个性状具有高亲优势,４个性状具有竞争优势;杂种Ｆ１各性状的竞争优势分别与父本、母本一般配合力效应值,父母本一般配合力效应平均值和组合特殊配合力效应值均有不同程度的相关,而以父母本一般配合力效应平均值与竞争优势的相关最密切且稳定。     

水稻籼粳中间型RIL系主要农艺性状杂种优势分析

分析了遗传背景相同的籼粳中间型重组自交系（RIL）9个品系与5个籼、偏籼型光温敏核不育系杂交的F1主要农艺性状的杂种优势．结果表明：9个农艺性状均表现为正向超亲优势,以单株产量、穗实粒数、株高和穗总粒数表现的优势较强,有效穗数、结实率和千粒重表现的优势较弱;F1单株产量仅与父本穗长呈显著负相关,而与杂种有效穗数、穗实粒数、结实率和千粒重呈极显著和显著正相关;F1单株产量的超亲优势与父本单株产量、有效穗数、结实率均呈极显著负相关,与父本抽穗天数和千粒重却呈显著负相关,而与杂种的抽穗天数、有效穗数、穗实粒数、结实率和千粒重优势呈极显著正相关．亚种间杂交稻超高产的获得关键在于要协调好产量目标、亲本产量构成因素和其杂种优势三者的关系．     

水稻杂种一代优势规律的初步研究

<正> 在农业生产上,杂种优势的利用是一项有效的增产途径。近几年来,我国水稻杂种利用的研究取得了显著成绩,但怎样进一步选育出早、丰、抗、优的新组合,在理论和实践上都没有很好的解决。为了给选育杂交水稻新组合提供理论依据,现将1981年的实验结果分析如下。     

高丹草及其亲本种子胚差异蛋白质组学分析

 高丹草是综合高粱和苏丹草双亲优良性状的一年生禾本科饲草,其杂种优势特别明显,但杂种优势形成机理还不明确。为了揭示高丹草杂种优势形成机理,本研究以杂种高丹草及其亲本的成熟胚为试材,利用Label free结合质谱技术,采用生物信息学分析方法在蛋白质组学水平进行研究。研究结果鉴定出差异蛋白124个,其中加性积累蛋白48个,占差异蛋白总数的38.71%,加性积累蛋白中上调蛋白19个,下调蛋白29个。鉴定出非加性积累蛋白为76个,占差异蛋白总数的61.29%,非加性积累蛋白的表达模式以超高亲表达所占比例最大（29个）,其次是偏高亲表达模式（18个）,偏低亲表达模式次之（14个）,另外还有超低亲表达模式（10个）,以及不属于该四种表达模式蛋白5个,因此,加性积累蛋白在高丹草成熟胚杂种优势形成上起主导作用。加性与非加性积累蛋白涉及多个功能组,主要是胁迫响应、碳水化合物代谢、转录调控、发育调控、信号转导、蛋白质代谢等功能类别。     

Relationship between differ- ential gene expression pat- terns in functional leaves of maize (Zea mays L.) at milk filling stage and heterosis using cDNA-AFLP

The genetic mechanism of heterosis has been one of the most challenging subjects in life science since the 20th century. However, because of the complexity of its genetic basis and the limitations of research methods and means, there was no substantial progress in the research of heterosis from the beginning of the 20th century to the 1990s. The development in molecular biology and bio- technology, especially that in quantitative trait loci (QTL) mapping methods, has made it possible to resea…     

杂交水稻苗期生长优势与~(32)P、~(14)C在分蘖的分布

试验杂交水稻的分蘖数量除L301A×R29比不育系和常规高产品种“双桂36”较少外,D优63、D优64、青优中、协优64、威优64、威优35和华优63分别比其亲本和对照品种多,表现正显性超亲优势.青优中、协优64、威优64、威优35、华优63和D优63的分蘖数与~(32)P在分蘖中的分布(％)呈正相关.D优64、L301A×R29不呈正相关.D优63、D优64、协优64的分蘖数与~(14)C—同化物在化分蘖的分布(％)呈正相关,青优中、威优64、威优35华优63和L301A×R29不呈正相关.D优63、D优64、协优64和华优63的单苗干物重高于它们的亲本和对照品种.青优中、协优64、华优63、D优63、D优64的苗高也分别比其亲本和对照品种高.本文还讨论了杂交稻苗期生长优势、~(32)P和~(14)C在分蘖中的分布(％)与谷粒产量的关系.     

新澄杂种西瓜及其亲本的同工酶分析

对良种西瓜“新澄”杂种及其亲本的酯酶、过氧化物酶同工酶进行分析研究的结果表明,杂种与其亲本的同工酶酶谱有显著差异,杂种除了具有双亲的“互补酶带”外,还出现双亲所没有的“杂种酶带”;同时发现杂种优势与酶谱的变化有密切相关.应用同工酶分析法鉴定这种价值昂贵的杂种种子的纯度,有一定的经济价值.     

冠菌素对玉米节间伸长和产量性状的影响

 试验以常用玉米杂交种郑单958为材料,用0.001、0.01、0.1、1μmol/L冠菌素(COR)作处理,清水为对照,通过调查农艺性状、分析生理指标以及产量性状,研究COR对玉米节间伸长的影响.结果表明,随着COR处理浓度的增加,郑单958的株高、穗位高和节间长度均降低,0.01、0.1和1μmol/L COR处理的株高、穗位高以及第2-8节节间长度均低于对照,且差异达到显著或极显著水平.随着COR处理浓度的增加,伸长节间吲哚乙酸氧化酶(IAAO)、苯丙氨酸解氨酶(PAL)和过氧化物酶(POD)的活性均升高,除0.001μmol/L COR处理外,0.01、0.1和1μmol/L COR处理的IAAO、PAL和POD酶活性均高于对照,且差异达到极显著水平.0.001和0.01μmol/L COR处理的穗长、行粒数、穗重、穗粒重和产量,与对照相比,均呈显著或极显著增加,且随着冠菌素浓度的增加,各性状均呈降低趋势,说明低浓度的COR能增加玉米的产量.综合来看,既能延缓节间伸长生长,又能增加产量的最适COR浓度为0.01μmol/L,因此作为一种玉米延缓剂,COR有较好的应用前景.     

Relationship between differential gene expression patterns in functional leaves of maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) at milk filling stage and heterosis using cDNA-AFLP

To understand the molecular mechanism of maize heterosis ,differential gene expression patterns in the functional leaves of 35 maize hybrids relative to their parents involving 10 elite inbreds at milk filling stage were analyzed hy using cDNA-AFLP,the correlation analyses of various differential expression patterns with the performance and heterosis of main maize agronomic traits were evaluated.The main results were as follows:For uniparental specific expression ,significant positive correlations were detected with the performance of seed weight per ear and 100-seed weight at 0.01 and 0.05 probability levels respectively.For biparental specific expression ,significant negative correlations were detected with the performance of ear diameter and seed weight per ear at 0.01 probability level .For uniparental specific expression ,significant positive correlations were detected with the heterosis of ear diameter and seed weight per ear at 0.01 and 0.05 probability levls rspectively,For biparental specific expression .significant negtive correlation was detected with theheterosis of ear diameter at 0.05 probability level ,However,for F1-spectific expression,for fragments detected only in one parent and F1,and for fragments detected only in two parents or only in F1,no significant correlation was detected with the performance or heterosis of all agronomic traits surveyed.     

大麦株高与其过氧化物酶同工酶关系初探

对大麦不同株高材料过氧化物酶同工酶的研究表明:大麦株高与穗下第2节间的过氧化物酶活性呈显著负相关。与胚芽鞘、剑叶、幼叶和幼根无相关性;所有供试材料胚芽鞘和穗下第2节间的过氧化物酶酶谱基本无差异,都显示了6条公共谱带。     

冬春性小麦杂交世代主要性状配合力与杂种优势的研究

通过冬春性小麦杂交世代主要性状的配合力与杂种优势的研究表明:同一性状不同品种的一般配合力和特殊配合力相对效应存在较大的差异:特殊配合力效应值较高的组合,其杂种优势较强,杂种后代表现愈好,但还与亲本的一般配合力效应有关.因此在选择中必须注重亲本的一般配合力的选择.实践证明,京花2号和荆阿的殊特配合力效应虽表现稍差,但一般配合力效应较好,是两个具有较高利用价值的亲本.     

Detection of quantitative trait loci and heterotic loci for plant height using an immortalized F2 population in maize

A set of recombinant inbred lines (RIL) derived from Yuyu22, an elite hybrid widespread in China, was used to construct an immortalized F2 (IF2) population comprising 441 different crosses. Genetic linkage maps were constructed containing 10 linkages groups with 263 simple sequence repeat (SSR) molecular markers. Twelve and ten quantitative trait loci (QTL) were detected for plant height in the IF2 and RIL populations respectively, using the composite interval mapping method, and six same QTL were identified in the two populations. In addition, ten unique heterotic loci (HL) located on seven different chromosomes were revealed for plant height using the mid-parent heterosis as the input data. These HL explained 1.26%―8.41% of the genotypic variance in plant height heterosis and most expressed overdominant effects. Only three QTL and HL were located in the same chromosomal region, it implied that plant height and its heterosis might be controlled by two types of genetic mechanisms.     

Inheritance of resistance to Helicoverpa armigera of 3 kinds of transgenic Bt strains available in upland cotton in China

There are 3 kinds of transgenic Bt strains, Shanxi 94-24, Zhongxin 94, and R19, in upland cotton in China. Their transgenic Bt insect-resistance cultivars or hybrids have been developed and grown by farmers. Genetic studies indicate that the resistance of the 3 transgenic Bt cotton strains to Helicoverpa armigera is controlled by one pair of non-allelic dominant genes. Linkage relationship between the resistant genes of R19 and Shanxi 94-24 transgenic Bt strains shows that they may be inserted in the same chromosome. F₁ hybrids crossed among the 3 strains show that high levels of protection from feeding damage are the same as that of their parents. Therefore, there is no co-suppression phenomenon in many transgenic plants. The results presented here afford a fundamental reliance in developing transgenic Bt insect-resistant cultivars and exploiting the heterosis of hybrids in upland cotton.