Growth Analysis Using Classical and Curve-Fitting Methods in Relation to Productivity in Pearl Millet (Pennisetum americanum L. Leeke)

The factors controlling productivity (dry matter production) in a pearl millet ( Pennisetum americanum L. Leeke) hybrid BJ-104 and its inbred parents, J-104 and 5141-A , were investigated using the harvest interval and curve-fitting methods. During initial stages, the hybrid showed highest total dry weight, leaf dry weight and leaf area, than the inbred lines. However, with age these differences decreased considerably. The male parent attained total dry weight almost equal to the hybrid by d 45, whereas the female parent attained it by d59.
The derived growth parameters like RGR, LAR, LWR and SLA showed strong ontogenic decline. Further, considerable cultivar variations were also recorded. Importance of the growth parameters in determining productivity is discussed and it is emphasized that higher accumulation of dry matter during initial seedling stages may be an important factor.     

Enzymes of Ammonia Assimilation and Transamination in Relation to Hybrid Vigour in Pearl Millet (Pennisetum americanum L. Leeke)

Changes in the activities of enzymes of ammonia assimilation viz., glutamate dehydrogenase (GDH), glutamine synthetase (GS) and glutamate synthase (GOGAT), together with the activities of glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) were analysed in the topmost fully expanded leaf of pearl millet (Pennisetum americanum L. Leeke) hybrid BJ-104 , and its parents, J-104 and 5141-A , during the entire period of growth in field. Ammonia assimilation enzymes showed strong ontogenic trends and the hybrid attained activities either equal to the better (male) parent or showed better parental heterosis. In contrast to this both GOT and GPT activities were slightly higher than the poor (female) parent. The role of these enzymes in relation to chlorophyll synthesis and transport of metabolites from cellular compartments of C₄ plants, are discussed. Surveying the literature on attempts to propose biochemical criteria for hybrid vigour, it is proposed that there cannot be a universal criterion, rather rate limiting steps in different cultivars should be searched.     

Heterosis for yield and its physiological determinants in wheat

Heterosis in hybrid wheat varieties produced using a chemical hybridising agent was assessed in field experiments. Hyno Esta and its parents were compared in factorial combinations of four-seed rates (25–300 seeds m^–2) and two nitrogen fertilizer rates (0 and 200 kg N ha^–1) in 2001/02 and again in 2002/03. Hyno Rista and Hyno Renta and their parents were compared at two-seed rates in 2001/02. Hyno Rista and its parents were added factorially to the Hyno Esta experiment in 2002/03, while Hyno Renta and Hybred and their parents were compared at two seed rates in 2002/03. Mid parent heterosis for grain yield was found in three hybrids and two of these showed high parent heterosis. High parent heterosis in Hyno Esta over a range of sowing densities was mostly exhibited in total biomass but also, in one of two years, in harvest index. High parent heterosis in Hyno Renta was associated more with harvest index than with biomass. The heterosis for biomass in Hyno Esta resulted from greater interception of photosynthetically active radiation (PAR) than the male parent, with better radiation use efficiency than the female parent. In both seasons Hyno Esta achieved grain numbers per ear at least as high as the high parent for this trait (Audace), and combined this with mean grain weights at least as heavy as the high parent for mean grain weight (Estica). Much of the increased biomass and grain yield in the hybrid came late in the season as high parent heterosis was expressed for both maximum grain filling rate and grain filling duration. Heterosis was higher when nitrogen was applied than when withheld; only greater at lower seed rates when expressed in proportionate terms (e.g. as a percentage of the parents), rather than in absolute terms (e.g. t ha^–1); and greater in the year with the cooler and wetter summer.     

中棉所12及其选系配制的4个杂交棉幼苗期基因差异表达

以与中棉所12及其2个选系为亲本组配的4个杂交棉中棉所28、中棉所29、湘杂棉2号和冀棉18苗期的根和顶端叶为研究材料,采用cDNA-AFLP技术分析苗期杂交棉与亲本的根和叶基因差异表达,并用QuantitativeReal-Time技术加以验证.结果表明:(1)在4个杂交组合中,中棉所12选系是营养生长杂种优势高值亲本;(2)杂交种和亲本间存在显著的基因表达差异,可分为杂交种上调、单亲显性、单亲沉默、杂交种下调4种表达型.4个杂交组合在三叶期根和叶中差异表达基因的4种类型比例趋势基本一致,单亲差异表达型(包括显性和沉默表达)在根和叶中所占比例较高,杂种下调表达型所占比例较低,反映出苗期单亲差异表达型在杂种优势形成中起主要作用;叶部差异表达基因数目和比例(29.20%～46.09%)比根(15.65%～22.49%)高的多,说明叶中基因差异表达可能比根中基因差异表达对杂种优势形成作用更大;(3)高值亲本中棉所12选系与杂交棉共同表达的基因多于低值亲本与杂交棉共同表达的基因,从分子水平上证明中棉所12选系在杂交棉冀棉18、中棉所29和中棉所28的苗期营养生长杂种优势产生中起优势亲本的作用;(4)4种杂交组合差异表达基因(包含叶和根)占总表达基因的27.00%～34.56%,分析差异表达基因类型和4个杂交组合的关系发现,超显性效应占3.30%～7.17%,超低亲效应占2.62%～4.14%,低亲效应占5.65%～13.03%,显性效应和加性效应是主要的杂种优势效应,占79.52%～83.79%.多种杂种优势效应的并存说明杂种优势可能是多基因共同作用产生多种效应的结果;(5)超亲优势组合中棉所28的超显性效应占7.17%,明显高于其他3个表现中亲优势组合,说明杂交种上调表达型可能对苗期杂种优势产生起重要作用.     

杂交小麦抗坏血酸过氧化物酶基因克隆及其在种子老化中的潜在功能分析

以BS型二系杂交小麦BS1453/11GF5135及其BS1453(母本)、11GF5135(父本)的种子为材料,在BS1453/11GF5135中通过同源克隆获得抗坏血酸过氧化物酶基因TaAPX。该基因包含一个832 bp的ORF,共编码277个氨基酸。通过进一步生信分析预测miRNA与TaAPX基因的互作关系,发现TaAPX基因可能受miR396等抗逆及种子活力相关miRNAs的调控。另外通过蛋白互作预测分析,发现APX蛋白主要与氧化还原相关的酶互作反应。通过对不同老化时间的父母本及杂交种的胚进行qPCR及酶活性分析,发现TaAPX基因在杂交种及亲本中的表达趋势是先被诱导上调表达,后下调表达,但杂交种子内TaAPX基因的表达量在第7天才开始下降,而亲本种子内TaAPX基因的表达量在第5天开始下降,且miR396与TaAPX互为拮抗作用。随着老化时间的延长,亲本种子内APX酶活性表现为下降趋势,杂交种子内APX酶活性在第3天呈短暂下降趋势,随后上升,第9天开始下降,表明在老化条件下杂交种子内APX酶清除体内过氧化物的能力高于亲本,即杂交种抗老化能力高于其父母本,且TaAPX基因对种子活力的调控是一个复杂的多因素参与的调控过程。本研究为进一步研究BS型杂交小麦种子活力的分子调控机理奠定了一定的基础。     

利用DNA指纹技术进行玉米亲子鉴定方法研究

利用DNA指纹分析技术 ,分析了同母异父 5个杂交组合分别与其父母本之间的遗传距离 ,结果发现 ,每个杂交组合与其相应的父本之间的遗传距离最小 ,所有组合完全一一对应。因此 ,可以通过计算遗传距离来进行玉米亲子鉴定 ,只需计算出玉米杂交种与所有可能父本自交系之间的遗传距离 ,与其遗传距离最小的自交系就是该杂交种的真正父本。     

基于数字基因表达谱分析的茶树花不育基因挖掘

茶树每年都要开花结实,消耗大量的养分,导致茶树鲜叶产量减少和品质降低。了解茶树的不育机制有助于培育茶树不育品种。本研究以福鼎大白茶(父本)、佛香2号(母本)及其杂交后代(不育)茶树花为材料,利用数字基因表达谱技术对3个茶树花的c DNA文库进行差异基因表达谱分析。筛选出在父本花与子代不育花、母本花与子代不育花之间共有而在父本花与母本花之间没有的差异表达序列1219条,被认为是茶树不育性候选基因。GO功能显著性分析表明,这些基因功能中代谢过程、催化活性、水解酶活性表现为富集;KEGG代谢分析表明,差异表达基因涉及氨基酸、糖、次生代谢、植物信号传导途径以及能量代谢等过程。以植物激素信号转导通路分析发现,16个与生长素信号途径相关基因中,除5个ARF家族基因在子代不育花中上调表达外,其他的基因均下调,推测生长素信号转导是茶树花不育的重要因素。随机抽取5个基因进行实时荧光定量PCR验证,其结果与测序结果一致。本研究发现的不育候选基因可用于茶树花不育机制的深入研究和不育基因的筛选。     

大穗型超级杂交粳稻辽优3072生理生化特性研究

为了研究北方大穗型杂交粳稻超高产的生理基础,为选育大穗型的北方杂交粳稻提供育种理论。对北方大穗型超级杂交粳稻辽优3072进行了产量结构和生理特性的研究。结果表明:与大穗型恢复系C52和小穗稳产型推广品种辽粳294相比,辽优3072灌浆中后期,叶片与根系的SOD、CAT、POD活性高、Vc、脯氨酸、叶绿素与可溶性糖含量较高,根系MDA含量较低,从而使辽优3072叶片同化产物生产旺盛,根系不早衰,有利于抵抗衰老和逆境,这是大穗型杂交稻辽优3072获得超高产的生理生化基础。同时也探讨了辽优3072各生理生化指标与亲本之间的关系。辽优3072的叶片SOD和CAT含量与父本显著相关,总叶绿素含量与母本显著相关,根系中SOD含量与父本显著相关。     

利用SNP芯片解析油菜杂交种丰油10号的遗传基础

为解析高产稳产油菜品种丰油10号的分子遗传学基础,利用油菜60K SNP芯片对丰油10号及包括其2个亲本在内的20份骨干亲本系进行了基因型分析。结果表明：20份骨干亲本系间的遗传距离变幅为0.123~0.463,平均为0.348。丰油10号母本22A和父本P087-2间遗传距离为0.375,高于平均遗传距离。聚类分析将20份骨干亲本系划分为4个类群,其中母本22A归在类群Ⅰ,父本P087-2归在类群Ⅳ。基因组比较发现杂交种丰油10号与母本22A的相似性比例为64.77%,与父本P087-2的相似性比例为62.89%,其中有30.78%的基因组杂合区段来源于双亲不同基因型间的组合。同时发现丰油10号与父母本在19条染色体上的多态性比例存在比较大的差异。该研究为后续油菜品种的选育提供理论指导。     

Chlorophyll Content, Hill Reaction and PEPcase Activity in Relation to Hybrid Vigour in Pearl Millet during Early Seedling Growth

Three hybrids of Pennisetum americanum L. Leeke were analyzed for growth and photosynthetic components during early growth and compared with their respective parents. Growth in terms of shoot length, fresh weight and dry weight along with the chlorophylls, and Hill activity revealed better parental and/or mid parental heterosis in all the hybrids over their respective parents. However, PEPcase activity displayed heterosis only in BJ-104. In other two hybrids no heterosis over the parents could be observed indicating thereby that the activity of this enzyme may not be rate limiting in parental lines.
Nevertheless, it appears that in pearl millet hybrids improved photosynthetic apparatus as observed in chlorophyll contents and Hill reaction may be one of the early expressions of hybrid vigour.     

玉米亲子代锌铁吸收和分配的研究

以玉米子粒高锌铁含量自交系NXR22（母本）、子粒低锌铁含量自交系NXR12（父本）及其配制的杂交种（F₁）为供试材料,比较双亲及其后代不同穗位的叶片、茎秆及子粒中锌和铁含量、积累量在吐丝期与成熟期间的差异,解析亲子代锌铁吸收与分配特征。研究结果表明:不同基因型玉米叶片、茎秆、子粒中锌铁含量和积累量存在显著差异。F₁不同穗位的叶片和茎秆锌铁含量介于双亲之间,且偏向于子粒锌铁含量高的亲本;锌铁积累量显著高于双亲,表现出明显的杂种优势。从吐丝期到成熟期3个供试材料不同穗位的叶片和茎秆锌铁含量和积累量均表现出一定程度的增加。F₁子粒中锌含量及积累量偏向于母本,表现出杂种优势;铁含量介于双亲之间,更偏向于母本。     

澳洲坚果人工杂交子代苗木生长量变异分析

为了认识澳洲坚果植株生长量性状的传递遗传规律,以澳洲坚果10个无性系品种为材料,正反交设计,共90个杂交组合,获得90个全同胞家系苗木。并对种子横径、苗木株高、地径及冠幅进行变异分析。结果表明,10个母本间种子横径达显著差异(P<0.05),同一母本所对应9个父本的组合间种子横径达显著(P<0.05)或极显著(P<0.01)差异,说明种子的大小不仅仅决定于母本,而且也受父本的影响。对苗木株高、地径和冠幅的分析表明,全同胞家系间差异显著(P<0.05),母本半同胞家系间差异显著(P<0.05),而父本半同胞家系间差异不显著。苗木生长量受父母本的基因共同决定,但母本影响的变异分量相对较大,父本影响的变异分量相对较小。     

普通小麦×八倍体小黑麦杂种F1代与亲本的形态学、细胞学和超微形态比较分析

以普通小麦京冬8号为母本,八倍体小黑麦劲松5号为父本,杂交获得杂种F1代。在对杂种F1代和亲本进行形态学和细胞学鉴定的基础上利用扫描电子显微镜对亲本和杂种F1代的叶表皮及气孔亚显微形态进行比较,得知3种供试材料叶表皮亚显微形态共同的特征是有气孔器、长细胞和毛细胞,细胞排列与叶脉平行,但母本普通小麦的叶表皮细胞轮廓清晰,排列较为整齐、光滑,气孔排列呈直线,哑铃状的保卫细胞有长短不一的刺毛;父本八倍体小黑麦的气孔周围有横向和纵向排列的嵴状凸起,气孔呈长方形、较大,排列方式总体也呈直线型,保卫细胞非常明显,但刺毛极少且短;杂种F1代无论是叶表面还是气孔的亚显微形态都与父本更相似,所不同的是叶表皮有刺毛,气孔大小介于两亲本之间。杂种F1代与双亲在形态学、叶表皮及气孔超显微形态特征上均有明显差异;超显微形态学指标也可以作为区分、鉴定远缘杂种和亲本的一项依据。     

Moricandia arvensis 与甘蓝型油菜属间杂种的获得及其生物学特性研究

以C_3作物甘蓝型油菜作父本与野生C_3—C_4中间型植物Moricandia arvensis作有性杂交,经子房培养和胚性芽挽救,获得了4个属间杂种,经腋芽繁殖使杂种群体增至数百株。RFLP分析结果显示,杂种核DNA具有两个亲本的特征指纹,而其细胞质中仅含母本Moricandia arvensis的线粒体DNA指纹。杂种多具33条染色体,为双亲配子染色体数之和。虽然杂种植株在大多数形态特征上表现为双亲的中间类型,但在某些性状上明显趋向某一亲本。杂种植株的一般特征是半匍匐性,浅裂叶,开浅黄花。其以CO_2补偿点很高,为C_3类型。花粉母细胞减数分裂不正常,有多价体产生。杂种雌雄性皆不育。用秋水仙素将杂种加倍为双二倍体后,仍然雄性不育。对进一步向芸薹属作物基因组中导入C_3-C_4基因的技术途径进行了讨论。     

Differential gene expression between wheat hybrids and their parental inbreds in seedling leaves

Differential display of mRNA was used to analyze the differences of gene expression in seedling leaves between heterotic hybrid/nonheterotic hybrid and their parental inbreds in order to study the molecular basis of heterosis in wheat. The results indicated that patterns of gene expression in hybrids differ significantly from their parents. Both quantitative and qualitative differences were observed. The quantitative differences include gene over-expression, gene under-expression in hybrid and dominant expression of highly-expressed parental genes in hybrids. The qualitative differences include silencing in hybrids of genes expressed either in male or female parent, and silencing in hybrids of genes expressed in both parents. Expression in hybrid of genes only expressed either in male or female parent was also observed. It was also found that some genes expressed at high level in heterotic hybrid were underexpressed or expressed at low level in nonheterotic hybrid. One differentially expressed cDNA fragment 4B was cloned and sequenced after being confirmed through Northern blot analysis. Homology search in GenBank proved that the cDNA fragment is a new sequence. The selection of primers for differential RNA display in wheat and the relationship between wheat heterosis and alteration of gene expression in hybrids as compared to their parental inbreds were also discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

杂交稻及其三系生育过程中RuBP羧化酶及有关光合酶的变化

研究了杂交稻汕优６３及其三系生育过程中叶片ＲｕＢＰ羧化酶／加氧酶及有关光合酶活性的变化,结果表明,供试材料ＲｕＢＰ羧化酶／加氧酶等参数的变化无本质的差异。杂交稻不同叶位叶片的ＲｕＢＰ羧化酶活性低于其母不育系,但与父本较接近。从ＲｕＢＰ羧化酶／加氧酶这一光合特征值来分析,杂交稻叶片并不存在光合优势。随着叶龄增加,杂交稻及其三系叶片的ＲｕＢＰ羧化酶／加氧酶、乙醇酸氧化酶、过氧化氢酶活性下降,而酸性磷酸     

Manova and discriminant analyses of phenotypic data as a guide for parent selection in kiwifruit (Actinidia deliciosa) breeding

Evaluation of seedling populations assists in identifying those plants most desirable as parents for a breeding programme. A multivariate analysis of variance (Manova) showed that the seedling populations from 6 kiwifruit (Actinidia deliciosa) crosses differed in their overall merit. Discriminant functions were then used to identify the characters most powerful in distinguishing between populations. The populations were placed in order of their function scores which represent overall merit, and the superior populations were determined. The results showed that `Bruno' was a superior female parent for the production of seedlings with high discriminant function scores for floriferousness (male offspring)and productivity and high vitamin C content (female offspring). One male parent D-1-20 was consistently superior to D-1-6 the other male parent. This revised version was published online in July 2006 with corrections to the Cover Date.     

斑茅割手密杂种后代真实性鉴定及遗传分析

以斑茅GXA87-36(♀)与割手密GXS79-9(♂)杂交获得的经形态鉴别为真杂种的后代材料GXAS07-6-1 (斑茅割手密杂合体)及其双亲为材料,利用体细胞染色体计数以及SSR、SRAP分子标记对杂种进行真实性鉴定,并利用SRAP分子标记对斑茅GXA87-36、割手密GXS79-9及其杂种后代遗传位点的传递进行分析。结果表明, GXA87-36体细胞染色体数为2n=60,GXS79-9体细胞染色体数为2n=64,其杂种GXAS07-6-1染色体2n=62,其杂交的染色体遗传方式为n+n;筛选出3对SSR引物和5对SRAP引物可分辨后代的真伪;利用71对SRAP引物扩增后代和双亲,检测到1 095个遗传位点,多态性位点数为800;母本有279个位点,其中有 79 %传递给其后代;父本有439个位点,其中有73%传递给后代;用NTSYS-pc2.10e软件计算Jaccard遗传相似系数,双亲间为0.474,后代与母本、父本间分别为0.696、0.752,表明后代GXAS07-6-1偏向父本遗传。     

长筒石蒜×红蓝石蒜杂种‘粉蓝石蒜’的生理特性分析

为研究以长筒石蒜为母本和红蓝石蒜为父本的杂交后代‘粉蓝石蒜’杂种优势,利用LI-6400 便携式光合分析仪测定了‘粉蓝石蒜’的光合参数,并对其生物碱的含量进行分析。结果表明：‘粉蓝石蒜’的净光合效率、气孔导度、胞间CO2浓度、蒸腾速率、叶绿素a 和b 含量及光合色素总量介于其2 个亲本之间;水分利用效率高于亲本;石蒜碱含量高于亲本,加兰他敏含量比亲本低。‘粉蓝石蒜’在抗旱性和药用活性成分（石蒜碱）含量方面表现出了杂种的优势。     

低温强光对超级杂交稻及其亲本苗期光合特性的影响

研究低温强光对两优培九和母本培矮64S（PA64S）以及父本中籼9311苗期叶绿素荧光参数和光合特性的影响。结果显示低温强光处理后，与父母本相比，两优培九的光合速率、PSⅡ原初光化学效率（Fv/Fm）和光化学猝灭系数（qP）降低和光化学猝灭系数（qN）增加较少，说明在低温强光下，超级杂交稻两优培九吸收的光能能较多的转化为化学能。试验结果表明在苗期杂交稻两优培九在低温强光下具有超亲偏母本的现象。