光敏核不育水稻中光敏色素的分析

本文报道了在育性转换敏感期光周期处理对光敏核不育水稻（农垦58S）及农垦58最新全展叶中光敏色素Ⅰ(PhyA)水平的影响PartI）．在10个光周期处理的最后一个暗期结束前,收获每株水稻的最上部二叶。PhyA用酶联免疫吸附测定法(ELISA)测定。 结果表明：0.5%(v／v)聚乙烯亚胺(PEI)可除去水稻叶片粗提液中干扰ELISA的物质;所用的ELISA专一性地检测水稻PhyA。和长日照(LD)处理相比，短日照(SU)处理导致农垦58S中PhyA的相对含量增加38.5%;而农垦58只增加18.5%。显然，在较长的暗期条件下（SD），农垦58S中PhyA的合成比农垦58快。SD处理下大量增加的PhyA可能和农垦58S的育性恢复有关。 上述结果也说明：在同一品种甚至不同品种的植株间，PhyA水平均易受光周期影响而剧烈变化。 为了进一步验证农垦58S中PhyA较快积累的推论，比较了农垦58s和农垦58幼苗（三叶期）在一延长暗期(24h)中PhyA的积累时程。和育性转换敏感期的植株相似，农垦58S幼苗中PhyA积累速度快于农垦58。在暗期开始6h后，这种差异更明显。这一结果证实了过去的假设：甲基化水平低的农垦58PhyA基因可能比农垦58PhyA基因更活跃地表达。 PhyA和PhyB同时存在于水稻叶片中。为了探讨PhyB是否参与农垦58S雄性不育的调节，在育性转换敏感期每日光期结束、暗期开始开始前进行短暂的FR照射实验(即end-of- dayFR irradiations)。EOD FR反应应由PhyB介导。和SD下的对照相比，经过10次EODFR处理(EOD FR+SD)的农垦58S植株抽穗和开花期都相应地推迟2天，而花粉败育率和种子结实率都没有变化。 EODFR处理抑制了农垦58的开花，但花粉育性几乎不受影响。 综上所述，可能是PhyA而不是PhyB参与调节农垦58S的雄性不育。 另外，本文采用免疫印迹(Immunoblotting or Western blotting)比较了农垦58S和农垦58黄化苗(3天龄)中PhyA的相对含量(PartⅡ)。 结果表明，RPA可以专一性地检测两品种中120KD多肽。该肽在照射R或FR后对内源蛋白酶水解的敏感性不同，照射FR后，该肽易降解产生116KD的片段;照射R后，相对较稳定。因此，上述120KD多肽是水稻PhyA。未观察到农垦58S和农垦58的PhyA在免疫原性、分子量及内源蛋白酶解水解带型有差异。定量分析表明农垦58s黄化苗中PhyA的相对含量比农垦58多40%。这一结果和上述光周期处理的结果是相辅相成的。由于干种子、以及吸涨36h以前的水稻胚中均检测不PhyA的存在，因此两品种间PhyA含量的差异是PhyA蛋白重新合成的结果。 活体低温(80K)荧光光谱分析表明：农垦58黄化苗（3天龄）具有典型光敏色素(主要为PhyA）的荧光发射，其最大波长为683.8nm，而农垦58S以及由其转育来的培矮64s都缺少明显的光敏色素峰。显然，农垦58S和农垦58的PhyA荧光光谱特性有所不同。这一差异是否和雄性不育有关仍待深入研究。 本文第三部分比较了农垦58S和农垦58黄化苗（6天龄）最初转到白光下(4h)合成叶绿素的情况。无论是短暂红光(R)处理或对照，农垦58幼苗合成叶绿素的量（在白光下4h）都多于农垦58S。由于R促进叶绿素合成的效果可被随后的远红光照射(FR)逆转，因此水稻幼苗中叶绿素合成是在光敏色素的控制下。FR逆转性在农垦58S中似乎更完全。连续FR（12h最有效）促进叶绿素合成的效果在农垦58S中更明显，但叶绿素合成的量（在白光下4h）仍是农垦58多。然而，对于自然光周期下生长的幼苗（2-4叶期），农垦58S的叶绿素含量明显高于农垦58。文中讨论了这种差异的可能原因。

水稻对大气二氧化碳浓度及温度升高的光合适应的研究

基于长期观测资料，众多大气环流模型预测在二十一世纪末大气中二氧化碳浓度将达到700μmolmol'I，地球表面年平均温度也将升高1.5-4.OoC。水稻是亚洲的主要粮食作物，为世界近三分之一的人口提供食物能源。这项工作的目的，是利用人工模拟环境，预测在未来全球气候变化，二氧化碳及温度升高的条件下，水稻的光合生理反应及随之而来的对其产量的影响。本研究是美国环境署( EPA)与国际水稻研究所(IRRI)合作研究项目“Effects of UV-B and Global Climate Change on Rice”的一部分． 在这项研究中，采用了特殊设计并直接建立在水稻田间的开顶式气室（open-top chambers）。在此之前还没有这样大规模的在水稻主产区的此类模拟研究，水稻在气室中渡过了从萌发到收获的整个生长过程。模拟环境条件有三个浓度的二氧化碳（包括现有大气浓度，在此基础上升高200及300 μmolmol-l���和两个温度（即：现有大气温度及升高4度）共六个处理。供试水稻品种四个：IR72，IR65598-112-2，IR65600-42-5-2-BSI-313和N22。在实验中我们发现，水稻品种（如：1R72）单叶光合速率（以二氧化碳气体交换速率计）受二氧化碳浓度促进，在水稻营养生长期，二氧化碳及温度对其光合有协同促进作用．然而，随着花期的到来，在高温条件下，叶片光合能力（photosynthetic capacity）下降，出现光合适应现象（Photosynthetic acclirnation）.水稻群体光合作用同样受到二氧化碳浓度促进，但在后期(Grain fill stage)这种促进作用消失;在高浓度二氧化碳下生长的大多数水稻品种的叶片中有较多的碳水化和物（可溶性糖和淀粉）积累．耐高温品种N22叶片中淀粉积累较少：叶片中氮素含量降低，同时发现Rubisco总活性相应降低，这与NCi曲线所示光合效率降低相吻合;通过叶片叶绿素荧光动力学测定，没有发现光系统光能转化效率的变化;水稻籽粒产量随二氧化碳浓度升高而增加，但温度升高使产量降低12.8-36.8%;不同品种对二氧化碳浓度的反应没有显著差别;在高温条件下，耐高温品生长在高二氧化碳浓度下表现良好。 本文系统地研究了水稻光合作用在二氧化碳及温度条件影响下，对二氧化碳浓度及光强变化的反应曲线，初次对水稻单叶与群体光合对二氧化碳浓度变化的反应做了实验性对比;讨论了温度升高对水稻在高浓度二氧化碳下发生光合适应的影响，对光合适应现象的可能机制做了探讨，并提出对未来大气二氧化碳浓度及温度升高条件下水稻适应品种筛选的可能方向。

植物根系、根区微生物对大气CO2浓度倍增的反应及其生态学意

预测下世纪中叶，大气CO_2浓度将高到目前的两倍（即达到700μ1•1~(-1)）。CO_2倍增对植物地上部的影响已经有了较多的研究，胆是由于方法学上的困难，至今关于倍增CO_2对植物根及根区微生物的研究仍是非常匮乏。本文应用国际上最新的根研究方法，以根系为中心，研究开顶式CO_2C熏蒸培养室中，CO_2倍增条件下根系与地上部，根系与根区微生物[共生的泡囊－丛枝菌根（VAM）真菌，非共生的土壤微生物]的关系。 1. CO_2倍增对根系的影响目前CO_2倍增对根系影响的研究多集中在根生物量的测定，或根／冠比值的测定，而善于其它参数如根长度则很少涉及，而根表面的反应目前还未见文献报道。本实验以幼苗期小麦“青323”（Triticum aestivum）、水稻“中作 29”(Oryza sativa)、大豆“科农4号”（Glycine max）、玉米“农大3138”（Zea mays）、甜高粱“M－81E”（Sorghum saccharatum）为材料，研究CO_2倍增对植物生物量的影响，发现CO_2倍增使C_3植物水稻、大豆的地上部、根系干重均显著增加，使小麦的根系干重显著增加，地上部无显著差异;C_4植物玉米和甜高粱的地上部和根系均没有显著反应。植物干重反应资料表明在光合产物的分配方面，C_3和C_4植物之间存在巨大的差异。 为了解根系获取土壤资源的能力的变化，我们对根系总长度和总表面积进行了分析。用样格交叉法研究根系长度的变化，结果显示，幼苗期的小麦、大豆的根系长度均被显著促进，尤其值得注意的是，尽管玉米根系干重没有显著改变，但是根长度已发生显著变化。同时应用研究根系表面积的最新方法－Na NO_2吸附法，研究发现幼苗期小麦、水稻和大豆的根系表面积在CO_2倍增条件下均显著增加，C_4植物玉米的根表面积亦有显著增加，但甜高粱的根表面积却没有显著反应，这说明即使在C_4植物类型中，根系表面积的反应在不同物种间仍存在很大差异。由于根长度和根表面积增幅大于根干重的增幅，所以推断在CO_2倍增条件下，植物根系细根比例增加，这有利于植物获取更多的养分。由于不同植物之间根系的反应不同，这将改变群落中原有的根系竞争关系，从而影响群落中物种的组成。 2. CO_2倍增对VAM真菌侵染强度和活力的影响本文应用NBT染色法，并结合浸染强度等级和活力等级标准，首次对CO_2倍增条件下，植物VAM真菌的侵染强度和活力的变化进行了检测。对比常规的酸性品红乳酸甘油法和NBT法，发现两者在显示侵染强度时元显著差异，但后者能同时用于侵染活力等级的研究。对幼苗期大豆以及不同生长期的小麦和玉米根系VAM真菌的侵染强度和活力进行观测，结果显示，倍增CO_2对大豆的侵染强度和活力均没有显著效应;使幼苗期玉米的侵染强度显著增加，但侵染活力无显著差异，但随生长期的推移，侵染强度所受的CO_2倍增效应逐渐减小，与14天苗龄（DAP）和35DAP相比，侵染活力在22DAP时所受效应最大;使10DAP小麦的VAM侵染强度和活力均显著增加，而且这种效应在30DAP小麦中的表现与10DAP小麦的相同。说明C_3、C_4植物中，菌根真菌对CO_2倍增反应不同，这也许是C_3、C_4植物对CO_2倍增反应不同的原因之一。倍增CO_2改善了VAM真菌的发育，所以较之于非菌根侵染植物，菌根侵染植物将因为CO_2倍增而获益更多，另一方面不同种植物中，VAM真菌的发育反应不同，这将使植物群落中，根系获取无机营养的竞争能力发生变化，最终影响植物群落的物种丰度和生物多样性以及群落的演替。 3. CO_2倍增对非共生土壤微生物的影响CO_2倍增使生长70天的小麦、垂柳（Salix babylonica）、藜(Chenopodium album)、繁穗苋（Amaranthus cruentus）品种“红苋K112”的地上部和根系的生物量增加。以这些植物所在土壤为材料，用氯仿熏蒸直接提取法研究土壤微生物生物量C（C_(mic)）和生物量N（N_(mic)）的变化，发现CO_2倍增尽管使各类型植物的C_4植物）土壤中C_(mic)的变化趋势不完全相同（小麦和藜所在土壤的C_(mic)下降，垂柳中C_(mic)升高，而在繁穗苋中无显著差异），但N_(mic)在各物种所在土壤中均有不同程度的上升，在繁穗苋中增幅最大。C_(mic):N_(mic)比值在4个物种所在土壤中均明显下降，这意味着CO_2倍增后在植物生长后期，土壤微生物活性提高，分解植物凋落物和土壤中其它有机质的能力加强，从而改善贫瘠土壤中有机质质量。 4.CO_2倍增对植物呼吸和光合作用及C素积累的影响 1）CO_2倍增对植物暗呼吸的影响：以杜仲（Eucommia ulmoides）、紫花苜蓿(Medicago sativa)和玉米等10种植物的离体成熟叶片或整株为材料，研究不同测定温度（15～35 ℃）下，CO_2倍增对植物暗呼吸的影响。结果表明：在较低温度（15 ℃、20 ℃）下，CO_2倍增对植物暗呼吸没有显著效应;在较高温度（30 ℃、35 ℃）时，多数被测植物的暗呼吸显著增强。由于植物在不同温度时它们的暗咱吸受CO_2倍增的促进幅度不同，这将导致不同地区（环境温度不同）的植物暗呼吸反应有差异，而且由于不同物种的暗呼吸增幅不同，综合光合效应，它们的生物量的反应也会不同。 2）CO_2倍增对整株植物的CO_2气体交换及植物C素积累的影响：利用自行设计的一套CO_2气体测定装置，首次尝试同步测定CO_2倍增条件下幼苗期小麦地下部和地上部的气体交换在昼夜24小时内的变化及C素的积累。发现CO_2倍增不仅使小麦地上部C素的积累增加，也使地下部释放的C素增加，但整株植物的C素收入仍高于对照两倍多，这从植物与环境的CO_2气体交换角度为CO_2倍增促进植物生物量的增加提供了依据。并首次提出：植物的整体性及植物所在的环境条件（主要是温度和光照强度）决定着植物暗呼吸对CO_2倍增的响应方式：被抑制或无效应。

Microcalorimetric studies on the thermogenesis of energy release of mitochondria isolated from rice

After isolation from rice mitochondria still have activity and can live for a long time by using its stored nutrients. The thermogenesis curves of energy release of the mitochondria isolated from variant strains of rice have been determined by using an LKB2277 bioactivity monitor. The differences in shape of the curves and the thermodynamic and kinetic characteristics of the thermogenesis of the mitochondria have been compared. The thermodynamic and kinetic parameters of energy release of the mitochondria in the thermogenesis increasing stage have been calculated, and the experimental thermokinetic equations of the thermogenesis have been established. (C) 2001 Elsevier Science B.V. All rights reserved.

The role of plants in channel-dyke and field irrigation systems for domestic wastewater treatment in an integrated eco-engineering system

Eight kinds of plants were tested in channel-dyke and field irrigation systems. The removal rates of TP, phosphate, TN, ammonia, CODcr and BOD, in the channel-dyke system with napiergrass (Pennisetum purpurem Schumach, x Pennisetum alopecuroides (L.) Spreng American) were 83.2, 82.3, 76.3, 96.2, 73.5 and 85.8%, respectively. The field irrigation systems with rice I-yuanyou No.1(88-132) (Oryza sativa L.) and rice II- suakoko8 (Oryza glaberrima) had high efficiency for N removal; the removal rate were 84.7 and 84.3%, respectively. The mass balance data revealed that napiergrass, rice I and II were the most important nutrient sinks, assimilating more than 50% of TP and TN. Plant uptake of N and P as percentage of total removal from wastewater correlated with biomass yield of and planting mode. (C) 2000 Elsevier Science B.V. All rights reserved.

Research on the ultrafast fluorescence property of thylakoid membranes of the wild-type and mutant rice

A high yielding rice variety mutant (Oryza sativa L., Zhenhui 249) with low chlorophyll b (Chl b) has been discovered in natural fields. It has a quality character controlled by a pair of recessive genes (nuclear gene). The partial loss of Chl b in content affects the efficiency of light harvest in a light harvest complex (LHC), thus producing the difference of the exciting energy transfer and the efficiency of photochemistry conversion between the mutant and wild-type rice in photosynthetic unit. The efficiency of utilizing light energy is higher in the mutant than that in the wildtype rice relatively. For further discussion of the above-mentioned difference and learning about the mechanism of the increase in the photochemical efficiency of the mutant, the pico-second resolution fluorescence spectrum measurement with delay-frame-scanning single photon counting technique is adopted. Thylakoid membranes of the mutant and the wild-type rice are excited by an Ar+ laser with a pulse width of 120 ps, repetition rate of 4 MHz and wavelength of 514 nm. Compared with the time and spectrum property of exciting fluorescence, conclusions of those ultrafast dynamic experiments are: 1) The speeds of the exciting energy transferred in photo-system I are faster than that in photo-system II in both samples. 2) The speeds of the exciting energy transfer of mutant sample are faster than those of the wildtype. This might be one of the major reasons why the efficiency of photosynthesis is higher in mutant than that in the wild-type rice.

黄土塬区三种豆科牧草的土壤养分剖面分布特征与平衡

为了解豆科牧草短期种植对土壤养分环境影响的进程和规律,通过田间试验对沙打旺、苜蓿和胡枝子等3种豆科牧草以不同密度单播、混播对土壤有机质、全氮、全磷剖面分布和平衡输出的影响进行了定性和定量分析。所有处理土壤全氮和有机质含量在土壤剖面2m深度范围内均呈典型的"S"形分布,全磷呈抛物线形分布。单播牧草固氮能力与播种密度呈正相关;苜蓿固氮能力最强,高密度下表观生物固氮量达507.5kg·hm-2。沙打旺生长1年可使土壤有机质平均净增3.51%。沙打旺和苜蓿全磷平均输出比率分别为43.14%和40.24%,显著高于胡枝子(23.74%);胡枝子与沙打旺、苜蓿的两两混播处理和3种牧草混播处理平均全磷输出比率分别为20.73%、26.33%、25.83%。试验结果表明,3种豆科牧草均可显著提高土壤有机质累积,沙打旺和苜蓿对土壤全氮和全磷的消耗显著大于胡枝子,但前两者的固氮能力也强于后者。以适当密度进行的不同牧草混播处理由于种间良性竞争和共生协调作用可优化混播群体对土壤养分的消耗利用。

水稻对伴生杂草的识别与响应

植物个体间的相互识别与响应是植物行为研究的中心问题之一，水稻与伴生杂草间识别与响应过程的研究对于阐明水稻与稻田杂草间的生态学关系具有重要意义。本研究以化感和非化感水稻各两个品种为研究对象，重点研究了水稻在伴生稗草情况下的可塑性响应，并探讨了这一响应行为可能的机制。同时研究了水稻根系分泌物及其化感物质对土壤真菌的影响。 研究结果表明： (1) 盆栽条件下与稗草伴生时，化感品种PI312777、华丰占1号和非化感品种辽粳-9能通过生物量增加而对稗草产生可塑性响应。田间条件下与稗草1:1伴生时，PI312777地上生物量增加了12%，而非化感品种辽粳-9和华粳籼1号地上生物量则分别减少33%和35%；除辽粳-9外，其余三品种水稻繁殖生物量均显著增加，其中PI312777增加26%。结果暗示化感品种水稻PI312777的竞争优势不仅源于其能向土壤释放比非化感品种水稻更多的化感物质，与稗草伴生时能产生更多生物量也应是其具有较强竞争力的主要原因。 (2) 化感品种水稻能对伴生稗草产生以特征次生物质含量升高为表征的可塑性化学响应，表明化感品种水稻在生理和行为方面的可塑程度均高于非化感品种水稻。在水培条件下水稻对马唐产生较强的化学响应，显示水稻能通过杂草根系分泌的信息物质对不同杂草进行选择性识别。 (3) 稗草伴生对化感品种水稻生长土壤的速效养分影响不显著，但PI312777生长土壤中的微生物生物量C显著升高87%，其土壤微生物群落结构与非化感品种水稻显著不同。表明化感品种水稻与稗草伴生时的可塑性行为不是水稻对土壤营养水平响应的结果，而是对稗草和水稻根分泌物共同影响形成的特征土壤微生物群落结构的间接反馈。 (4) 水稻根系分泌物和阿魏酸、苯甲酸能促进真菌生长，而黄酮和黄酮甙则造成真菌种群数量减少。病原真菌尖孢镰孢菌和立枯丝核菌生长均受黄酮抑制，水稻根分泌物对尖孢镰孢菌生长具有抑制作用。结果表明水稻能通过根分泌物中的化感物质对病原真菌产生化学防御。

水稻木质素在土壤中的降解及其效应

本论文主要以化感水稻PI312777和非化感水稻辽粳-9木质素为试验材料，通过土壤添加实验，分析水稻木质素降解产生的酚酸种类与含量，评价其降解产物对稗草及微生物的影响；同时测定水稻不同生育时期稻田土壤中酚酸种类和含量的变化。结果表明： (1)木质素降解过程中会释放多种酚酸，各酚酸含量变化显著。随着木质素的降解，释放出的酚酸含量呈现先升高再降低的趋势。木质素降解产生的酚酸含量的变化与其是否来自化感水稻品种无关，而与木质素的浓度有关。 (2)木质素对稗草产生显著抑制效果，且抑制程度与木质素的浓度呈负相关关系。木质素对稗草的抑制程度随培养时间呈现增强-减弱-增加的变化趋势。木质素对稗草的影响与其来源的水稻品种特性无关。 (3)培养到第四周木质素对细菌和放线菌产生显著抑制活性，并且对细菌和放线菌抑制效应随培养时间增加而减弱。木质素对细菌和放线菌的影响与其来源的水稻品种和浓度无关。在整个共培养时间内，木质素对真菌种群数量产生显著的影响。在其培养的前30天，随培养时间增加其促进作用增强，而后促进作用减弱。木质素的添加量及其来源的水稻品种均对真菌的种群数量产生显著影响。 (4)田间条件下，土壤中酚酸的含量随水稻生育期和品种的不同而存在显著差异。水稻幼苗期田间土壤中酚酸的含量较多，成熟期最少。而三种土壤游离态酚酸—香草酸、4-香豆酸和阿魏酸在水稻不同生育时期田间土壤中的含量变化不大。生测显示,田间土壤中的游离酚酸含量在水稻整个生育时期都低于酚酸对稗草生长的抑制浓度。稻田土壤中的酚酸含量与水稻品种及生育时期无关。

同源四倍体水稻三系亲本的遗传差异、细胞遗传学比较研究及低直链淀粉含量突变体Wx基因序列分析

同源四倍体水稻（2N=4X=48,AAAA）是由二倍体水稻（2N=2X=24,AA）通过秋水仙素诱导染色体加倍后得到的新品系，具有优良的抗病性以及较高的蛋白质含量。因此，在四倍体水平上挖掘水稻的增产潜力成为水稻育种的新手段。同源四倍体水稻具有很强的遗传可塑性和很弱的遗传保守性，利用其作为水稻远缘杂交的桥梁，从野生物种中不断地引进有益的基因，这将有助于杂交水稻的多代利用和固定水稻的杂种优势。但是迄今为止，还没有关于同源四倍体水稻遗传多样性，遗传背景的报道。目前世界关于同源四倍体水稻的研究主要集中在中国，主要研究方向为培育、筛选结实正常的亲本材料，配置和筛选结实率正常或接近正常的组合。经过几十年研究，虽然在材料构建，细胞学研究等方面取得了较大进展，但同样由于结实率低的瓶颈问题未解决，而使多倍体水稻育种未能取得实质性进展。而近年来一些关于同源四倍体水稻低结实率机理的细胞学研究也由于缺乏统计学数据而缺乏说明性。本文用SSR标记，对选取的36个结实率正常同源四倍体水稻三系亲本和14个来源二倍体亲本，分析他们的遗传差异和群体遗传结构。本文还利用我们培育的高、低结实率的同源四倍体水稻恢复系、优良保持系和杂种F1及二倍体对照为材料，进行系统深入的细胞遗传学研究，进一步探讨同源四倍体水稻有性传递后代的发育过程，探索分裂期染色体行为特征与遗传性状稳定性的关系，为进一步选育多倍体水稻品种并将其应用于生产提供理论依据。同源四倍体水稻突变株D4063-1直链淀粉含量比来源二倍体明恢63下降一半,即其直链淀粉含量为5.23%，为研究其直链淀粉含量下降的原因，本文还根据普通水稻Wx基因设计引物，扩增测序获得了D4063-1Wx基因的全序列，与已报道Wx基因进行比对分析，并根据D4063-1和籼稻、粳稻的序列差异并根据D4063-1在该片段上的特征序列位点设计了用于识别D4063-1的寡核苷酸片段,为快速、准确的鉴别低直链淀粉的D4063-1创造了条件。 SSR标记具有基因组分布广泛、数量丰富、多态性高、容易检测、共显性、结果稳定可靠、实验重现性好、操作简单、经济、易于高通量分析等许多优点，被认为是用于遗传多样性、品种鉴定、物种的系统发育、亲缘关系及起源等研究的非常有效的分子标记。本研究选取了中国科学院成都生物所培育的同源四倍体和二倍体水稻亲本，并用36个微卫星标记进行了遗传差异和种群遗传结构分析。在50个品系中，我们观察到较高水平的多态性，每基因等位基因数（Ae）分布于2至6之间（平均值3.028），多态性信息含量（PIC）分布于0.04至0.76之间（平均值0.366）；期望杂合度（He）分布于0.04至0.76之间（平均值0.370），Shannon指数（I）分布于0.098至1.613之间（平均值0.649）。同源四倍体品系的等位基因数，期望杂合性和Shannon指数都比二倍体品系高。在供试50个品系中，较多材料均发现Rare基因，根据SSR多态性指数我们构建了同源四倍体和二倍体水稻的核心指纹库。F-统计值表明遗传差异主要存在于同源四倍体品系中（Fst=0.066）。聚类分析结果表明50个品系可以分为4个组。I组包括所有的同源四倍体和二倍体籼稻保持系，以及一个同源四倍体籼稻雄性不育系及其来源二倍体。II组仅包括IR来源的品系。III组比II组和IV组更复杂，包括同源四倍体和二倍体籼稻恢复系品系。IV组包括同源四倍体和二倍体粳稻品系。此外,由于等位基因及配子的遗传差异,同源四倍体与二倍体品系中存在单位点和双位点的遗传差异。分析结果表明,二倍体和四倍体水稻基因库的不同,其中遗传变异可以区分四倍体与二倍体水稻。同源四倍体水稻具有长期而独立的遗传性，我们能够选育并得到与二倍体亲本相比有特殊优良农艺性状的品系。 本研究以高结实率的同源四倍体水稻恢复系DTP-4、D明恢63及优良保持系D46B为材料进行农艺性状及细胞遗传学比较研究。DTP-4、D明恢63及保持系D46B的的染色体组成均为2N=4X=48，花粉母细胞具有较为理想的减数分裂行为，配对染色体的比率在99%以上，这与理论染色体组构成相符。DTP-4和D明恢63PMC减数分裂各个时期单价体和三价体的比例都非常低，而在MI， PMC观察到较多的二价体和四价体且四价体多以环状形式出现，其最大频率的染色体构型分别为12II 6IV和10II 7IV。恢复系DTP-4和D明恢63在MI四价体频率分别为2.00/PMC和2.26/PMC，而保持系D46B在MI四价体频率为6.00/PMC，极显著地高于恢复系品系，表明保持系D46B具有更好的染色体配对性质；AI保持系D46B的染色体滞后频率为10.62%，远低于恢复系材料DTP－4和D明恢63的19.44％和23.14％，接近二倍体对照明恢63的7.30%水平；TI保持系D46B具有比恢复系更低频率的微核数。而在TII，D46B的正常四分小孢子比率不但高于恢复系品系甚至高于二倍体对照。对高低结实率的同源四倍体水稻恢复系和杂种F1代的花粉育性，结实率和细胞遗传学行为进行了比较研究。DTP-4, D明恢63, D46A´DTP-4和D46A´D明恢63的花粉育性和结实率比D什香和D46A´D什香显著提高。减数分裂分析的结果表明，DTP-4，D明恢63，D什香，D46A´DTP-4，D46A´D明恢63和D46A´D什香其减数分裂染色体构型分别为：0.05I +19.96 II (9.89棒状+10.07环状) +0.01III + 2.20 IV, 0.11I +19.17 II (8.90 棒状+10.37 环状) +0.09III + 2.26 IV + 0.01 VI, 1.33I +9.46 II (4.50 棒状+4.96 环状) +0.44III + 6.02 IV + 0.09VI + 0.09 VIII, 0.02I +14.36 II (6.44 棒状+7.91 环状) +0.01III + 4.80IV + 0.01VIII, 0.06 I +17.67 II (11.01 棒状+6.67 环状) +0.06 III + 3.10 IV + 0.01 VI and 1.11 I +11.31 II (5.80 棒状+5.51 环状) +0.41 III + 5.63 IV+0.03VI+0.03VIII。在同源四倍体水稻恢复系和杂种F1代材料中，最常见的染色体构型为16II +4IV和12II +6IV。在减数分裂过程中，结实率较高的材料染色体异常现象较少而结实率较低的材料染色体异常现象较严重。在杂种F1代中，二价体的比例要低于其相应的恢复系亲本，同样的，单价体，三价体和多价体的比例相比其恢复系亲本也偏低。然而，在减数分裂MI，杂种F1代中四价体的比例要显著高于其恢复系亲本。在中期I，每细胞单价体的比例和花粉育性呈现出极高的负相关(-0.996)，当单价体数目升高时，花粉育性下降。其次是每细胞三价体的比例(-0.987)，之后则是每细胞多价体的比例与花粉育性的负相关(-0.948)。但是统计分析表明，二价体和四价体的比例对花粉育性和结实率没有显著影响。这一结果表明出了花粉育性和细胞减数分裂行为的相关性，同源四倍体的减数分裂行为为筛选高结实率的同源四倍体种系提供了理论依据。 突变体是遗传学研究的基本材料。利用突变体克隆水稻基因,并进而研究基因的生物学功能是水稻功能基因组学的重要研究内容。本课题组在多年的四倍体水稻育种研究中已获得多个低直链淀粉含量突变体，其中一些突变体在直链淀粉含量下降的同时，胚乳外观也发生了显著改变，呈半透明或不透明。同源四倍体水稻突变株D4063-1直链淀粉含量比来源二倍体明恢63下降一半,即其直链淀粉含量为5.23%。为研究其直链淀粉含量下降的原因，我们根据普通水稻Wx基因设计引物，扩增测序获得了D4063-1Wx基因的全序列，与已报道Wx基因进行比对分析；同源四倍体水稻D4063-1Wx基因最显著变化为在外显子序列中发生了碱基缺失，导致移码突变，在第9外显子终止密码子提前出现。D4063-1Wx基因碱基位点的变化还导致了其序列上的酶切位点的变化,对常用限制性内切酶位点分析分析结果表明同源四倍体水稻相对于籼稻和粳稻多了2个sph1酶切位点，相对于粳稻减少了6个Acc1，增加了4个Xba1，1个Xho1，1个Pst1和1个Sal1酶切位点。聚类分析表明D4063-1Wx基因序列与籼稻亲源关系较近，由此推测D4063-1Wx基因来源于籼稻的Wxa基因型。另外，根据D4063-1Wx基因的碱基差异，我们推测D4063-1Wx基因外显子碱基变化导致的RNA加工障碍是其直链淀粉降低的主要原因，并可能与其米饭较软等品质相关。本文还根据D4063-1和籼稻、粳稻的序列差异并根据D4063-1在该片段上的特征序列位点设计了用于识别D4063-1的寡核苷酸片段,并作为PCR反应的引物命名为AUT4063-1,将该引物与我们设计的扩增普通籼稻、粳稻的Wx基因引物F5配合使用建立了识别D4063-1的显性和共显性两种检测方式的分子标记,为快速、准确的鉴别低直链淀粉的D4063-1创造了条件。 研究同源四倍体水稻基因组的遗传差异，探索同源四倍体水稻的遗传规律，研究分裂期染色体行为特征与遗传性状稳定性的关系,旨在揭示四倍体水稻中同源染色体配对能力的遗传差异，为进一步选育多倍体水稻品种并将其应用于生产提供理论依据。 Autotetraploid rice (2N=4X=48, AAAA) is a new germplasm developed from diploid rice (2N=2X=24, AA) through chromosomes doubling with colchicines and is an excellent resource for desirable resistance genes to the pathogens and high protein content. Therefore, heterosis utilization on polyploidy is becoming a new strategy in rice breeding. At present, the main research on autotetraploid rice centralizes in China. Breeding effort has been made to improve autotetraploid rice genetically, however, the progresses are limited due to higher degree of divergence between hybrid sterility and polygenic nature. But to date, almost nothing is reported about the genetic diversity, original and genetic background of autotetraploid rice. Despite several reports on cytological analysis of the mechanisms of low seed set in autotetraploid rice still the results are inconclusive due to lack the statistical evaluation. Therefore, the study on the mechanisms of low seed set in autotetraploid is a priority for rice breeding. Microsatellites or simple sequence repeats (SSRs) are the widely used marker for estimating genetic diversity in many species, including wild, weedy, and cultivated rice. In our research, genetic diversity and population genetic structure of autotetraploid and diploid populations collected from Chengdu Institute of Biology, Chinese Academy of Sciences were studied based on 36 microsatellite loci. For the total of 50 varieties, a moderate to high level of genetic diversity was observed at population levels with the number of alleles per locus (Ae) ranging from 2 to 6 (mean 3.028) and PIC ranging from 0.04 to 0.76 (mean 0.366). The expected heterozygosity (He) varied from 0.04 to 0.76 with the mean of 0.370 and Shannon’s index (I) ranging from 0.098 to 1.613 (mean 0.649). The autotetraploid populations showed a slightly higher level of effective alleles, the expected heterozygosity and Shannon’s index than that of diploid populations. Rare alleles were observed at most of the SSR loci in one or more of the 50 accessions and core fingerprint database of the autotetraploid and diploid rice was constructed. The F-statistics showed that genetic variability mainly existed among autotetraploid populations rather than among diploid populations (Fst=0.066). Cluster analysis of the 50 accessions showed four major groups. Group I contained all of the autotetraploid and diploid indica maintainer lines and a autotetraploid and its original diploid indica male sterile lines. Groups II contained only original of IR accessions. Group III was more diverse than either group II or IV and comprised of both autotetraploid and diploid indica restoring lines. Group IV included japonica cluster of the autotetraploid and diploid rices. Furthermore, genetic differences at the single-locus and two-locus levels, as well as components due to allelic and gametic differentiation, were revealed between autotetraploid and diploid varieties. This analysis indicated that the gene pools of diploid and autotetraploid rice are somewhat dissimilar, which made a variation that distinguishes autotetraploid from diploid rices. Using this variation, we can breed new autotetraploid varieties with some new important agricultural characters but the diploid rice has not. Cytogenetic characteristics in restorer lines DTP-4, DMinghui63 and maintainer line D46B of autotetraploid rices were studied. DTP-4, DMinghui63 and D46B showed the advantage of high seed set and biological yield. The meiotic chromosome behavior was slightly irregular in DTP-4, DMinghui63 and D46B. We observed less univalent, trivalent and multivalent at MI, but more bivalent and quadrivalent were observed. The most frequent chromosome configurations were 12II 6IVand 10II 7IV in restorer and maintainer lines, respectively. The quadrivalent frequency of DTP-4 and Dminghui63 at metaphase(MI) was respectively 2.00/PMC and 2.26/PMC. However that frequency of D46B was 6.00/PMC, which was greatly significantly higher than DTP-4 and Dminghui63. That indicates the maintainer D46B has better chromosome pairing capability in metaphase (MI). The frequency of lagging chromosomes of the maintainer D46B at anaphaseI (AI) was 10.62%, which was significantly lower than that of DTP-4(19.44%) and Dminghui63(23.14%) and nearly reaching the level of diploid CK(7.30%). In telophaseI (TI) maintainer D46B showed lower frequency of microkernel at TI and lower frequency of abnormal spores at telophaseII(TII). We also studied pollen fertility, seed set and cytogenetic characteristics of restorer lines and F1 hybrids of autotetraploid rice. DTP-4, DMinghui63, D46A´DTP-4 and D46A´DMinghui63 showed significantly higher pollen fertility and seed set than DShixiang and D46A´DShixiang. Pairing configurations in PMC of DTP-4, DMinghui63, DShixiang, D46A´DTP-4, D46A´DMinghui63 and D46A´DShixiang were 0.05 I+19.96 II (9.89 rod+10.07 ring)+0.01 III+2.20 IV, 0.11 I+19.17 II (8.90 rod+10.37 ring)+0.09 III+2.26 IV+0.01 VI, 1.33 I+9.46 II (4.50 rod+4.96 ring)+0.44 III+6.02 IV+0.09 VI+0.09 VIII, 0.02 I+14.36 II (6.44 rod+7.91 ring)+0.01 III+4.80 IV+0.01V III, 0.06 I+17.67 II (11.01 rod+6.67 ring)+0.06 III+3.10 IV+0.01 VI and 1.11 I+11.31 II (5.80 rod+5.51 ring)+0.41 III+5.63 IV+0.03 VI+0.03 VIII, respectively. Configuration 16 II+4 IV and 12 II+6 IV occurred in the highest frequency among the autotetraploid restorers and hybrids. Meiotic chromosome behaviors were less abnormal in the tetraploids with high seed set than those with low seed set. The hybrids had fewer frequencies of bivalents, univalents, trivalents and multivalents than the restorers, but higher frequency of quatrivalents than the restorers at MI. The frequency of univalents at M1 had the most impact on pollen fertility and seed set, i.e., pollen fertility decreased with the increase of univalents. The secondary impact factors were trivalents and multivalents, and bivalents and quatrivalents had no effect on pollen fertility and seed set. The correlative relationship between pollen fertility and cytogenetic behaviors could be utilized to improve seed set in autotetraploidy breeding. The amylose content of autotetraploid indica mutant Rice D4063-1 dropped by half than diploid Minghui 63, that is, its amylose content of 5.23%.The whole sequence of Waxy gene of D4063-1 is amplified and sequenced. And the discrepancy of bases is found comparing to the reported Waxy gene. The Waxy gene of autotetraploid Rice D4063-1 had a base deletion in exon sequence, which resulted frameshift mutation in exon 9 and termination codon occur early. The mutation of Wx also led to the change of some common restriction endonuclease sites. Results showed compared to indica and japonica, D4063-1 had two adding sph1 sites. Compared to japonica, D4063-1 had six decreasing Acc1, a adding Xho1, Pst1 and Sal1 restriction sites. Phylogeny analysis shows that the DNA sequence of Waxy gene of D4063-1 is closer to Indica, and we suppose that the Waxy gene of D4063-1 is origin from genotype Wxa. In addition, according to the base differences of Wx in D4063-1, we deduce that RNA processing obstacle led by base change of intron is the main cause to low the amylose content, and related to phenotype of its soft rice. Based on analysis of fragments of D4063-1, indica and japonica and according to the special point of the three species, primers as markers-AUT4063-I were designed for distinguishing the D4063-1 from other rice. Combining with primer pair F5, dominant and codominant ways were established for discriminating them., rapid and correct identification of D4063-1 from other rice could be done. The genetic analysis is important to ensure the original of autotetraploid rice, for maintaining the “distinctiveness” of autotetraploid varieties, and to differentiate between the various genetic background of autotetraploid rice. The autotetraploid breeding will benefit from detailed analysis of genetic diversity in the germplasm collections. Further investigation on mechanisms of meiotic stability should benefit polyploid breeding. These findings demonstrated opportunity to improve meiotic abnormalities as well as grain fertilities in autotetraploid rice.

水稻同源四倍体三系法杂种优势利用研究

水稻是重要的粮食作物，其产量的增加和品质的改良都是关系国计民生的大事。就我国现阶段的国情而言，水稻产量在现有水平上稳步提升仍是未来十几年甚至几十年农业生产最重要的目标之一。尽管根据“超级杂交水稻育种”的战略设想和水稻育种实践，通过不断地改进育种技术可望在更高的产量水平上进行水稻杂种优势利用，在稻属植物内还具有很大的产量潜力可以挖掘。然而，仅仅从现有的种质基础出发，要更大幅度提高水稻单产，实现“超级杂交稻”的目标也存在一些困难：现有的推广品种是二倍体，尽管种类众多，但是其基因组的来源相对单一；同时，水稻基因组DNA含量也是作物中最少的，基因组内寻求开发潜力有一定困难；水稻作为C3植物，光合利用效率不高也是制约水稻产量提高的因素之一。因此，寻求常规手段以外的技术突破或者方法创新，是实现“超级杂交稻”的目标的迫切需求。本研究利用秋水仙素能抑制细胞分裂中纺锤丝的收缩、使细胞染色体加倍的作用，对水稻幼穗诱导的愈伤组织细胞进行加倍，并分化出再生植株；创制出水稻同源四倍体新的种质材料，在此基础上选育水稻同源四倍体雄性不育三系材料，并实现水稻同源四倍体的三系配套，开展水稻同源四倍体杂种优势利用和四倍体杂交水稻选育研究，建立水稻同源四倍体杂种优势利用的新技术体系。这不仅有助于倍性水平杂种优势的开拓和利用，同时也将为我国新世纪“超级稻”育种研究开辟一条新的技术途径。 水稻幼穗诱导愈伤组织并分化成苗是一项成熟、简单的组织培养技术。本研究以普通二倍体水稻亲本为材料，用秋水仙素进行水稻的多倍体化诱导，创制同源四倍体水稻三系亲本材料并对其进行鉴定。多倍体化以秋水仙素诱导的愈伤组织培养为基础，研究不同秋水仙素浓度梯度和愈伤组织诱导培养基组合对诱导四倍体植株的影响。结果表明在MS+2,4 D 1.0mg/L+ KT0.2mg/L+ IAA0.2mg/L 和500mg/L���秋水仙素处理下，水稻愈伤组织染色体加倍（有最高的效率）效果较好，平均加倍频率可达25.26%，其中，材料CDR22和IR26诱导较易成功，加倍频率分别达到75%和26.5%；相对材料94109 1.3%加倍频率和冈46B 10.8%加倍频率，诱导率差异极显著。 对水稻四倍体材料进行了形态学鉴定结果表明，与二倍体水稻对照相比其株高、穗长、花粉育性等主要农艺性状，确定四倍体材料在穗长和千粒重两方面极显著提高，种子的长度和宽度也显著增长。对花粉育性鉴定，确认水稻四倍体不育系材料仍为不育，保持系材料自交和杂交可育，恢复系材料自交和杂交可育。对四倍体材料进行细胞形态、染色体数目等方面进行细胞学鉴定，经核型分析表明水稻四倍体材料具有48条染色体，是二倍体水稻的两倍。水稻四倍体材料根尖分生组织细胞与二倍体的根尖分生组织细胞相比，细胞体积、细胞核和核仁显著增大。四倍体三系材料在细胞有丝分裂中期均可规则排列在赤道板，并能均等地移向两极；后期观察中没有发现染色体分离滞后现象，分裂末期细胞能够形成大小相对均一的子细胞。水稻同源四倍体三系材料细胞分裂未见异常，植株生长发育正常。 从1996年至2006年，针对结实率、有效分蘖、着粒数和穗长等主要农艺性状，通过系谱选育的方法，对培育的同源四倍体水稻亲本材料进行了连续选择和改良，取得较好成效。表现为结实率的改良效果极佳，所有改良材料的平均结实率均呈上升趋势，如D237（29.70％→72.70％）、DTB（19.55％→53.21％）等。有效分蘖总体呈现上升趋势，但在不同的年份，如1998和2002存在较大的负向波动。部分材料改良效果明显，如D19B（5.87→13.50）、D什香 (7.00→12.00)等；同时一些材料如DTB和D明恢63虽然总体略有提高，但在不同的年份波动很大，因此存在较大改良阻力，原因还有待进一步研究。着粒数的改良上升趋势比较显著，除保持系的DTB之外，其余材料的平均着粒数有显著提高。穗长的改良阻力较大，虽然不同材料总体上有所提高，但效果并不显著，并且不同年份有较大负向波动（2001）。此外还对株高、剑叶长等性状也进行了选择，但效果不显著，原因有待进一步提高。同源四倍体材料产量相关性状遗传改良幅度不一致，保持系和恢复系间的遗传改良效果也存在差异。这为同源四倍体水稻的进一步利用打下了良好的基础。 籼稻和粳稻亚种间杂交及杂种优势利用的主要障碍就是其低的结实率。而同源四倍体杂交水稻的研究为提高杂交水稻的杂种优势利用创造了新的途径。本研究通过随机区组设计方案，挑选性状优良的二倍体水稻材料，包括雄性不育系，保持系和恢复系进行秋水仙素诱导加倍，从而获得同源四倍体水稻对应的三系材料。利用选育的优良水稻同源四倍体三系材料，配制7个杂交组合，杂交F1代与其恢复系亲本进行比较，用于计算超亲优势（HB）；而杂交F1代与生产上大面积推广的二倍体杂交品种汕优63进行比较，用于计算杂种优势。结果显示，同源四倍体杂交水稻的超亲优势表现为：每株有效穗变化幅度为1.4%至105.9%，总粒数为0.5%至74.3%，每穗实粒数为17.6%至255.7%，结实率为9.6%至130.4%。这些农艺性状的改良使得这7个杂种F1的理论产量的超亲优势高达64.8%至672.7%。小区试验中四倍体杂交水稻组合T461A/T4002和T461A/T4193分别比二倍体对照汕优63提高46.3%和38.3%以上，除一个品种以外所有品种产量均接近或高于汕优63的产量。同源四倍体水稻强大的杂种优势表明，亚种间杂交育性低的问题可通过四倍体化及强化选择来解决。此外，同源四倍体杂交水稻器官的巨大性也是其产量提高的有利因素，水稻同源四倍体三系杂种优势利用研究具有一定的理论价值和商业生产潜力。 Rice is one of the major food crops, the improvement of the production and quality of it is an important thing related to the people's livelihood. On China's current national conditions, steadily increase of the rice yield based on the current level is still one of the most important goals in the next decade or even decades of agricultural production. According to the "super hybrid rice breeding" the strategic and rice breeding practice, improvement of the use of hybrid rice heterosis through continuous improvements in breeding technology is expected to get a higher level of rice yield, there are also a great yield potential can be exploited. However, there are also some difficulties to increase rice yield obviously and implement the goal of "super hybrid rice" based on the existing germplasm: Rice varieties in promotion are diploid, although there are many varieties, but their genome are from a comparatively single source; Meanwhile, the rice genome DNA are the least among the crops, it is difficult to exploit the development potential within the genome; Rice as C3 plants, photosynthetic efficiency is not high, it is one of the factors constraint rice yield. Therefore, seeking technological breakthroughs or innovative methods different from conventional means is the urgent needs to reach the target of "super hybrid rice". Using colchicine inhibit spindle contraction during cell division, double the cell chromosome, we induced callus cells from rice panicle to be doubled, and differentiated regeneration; we created a new autotetraploid rice germplasm material, and on that basis we bred male sterility three line autotetraploid rice materials, and the achieved the three line rice autotetraploid matchmaking, researched in autotetraploid rice heterosis usage and tetraploid hybrid rice breeding, constituted a new technology system of autotetraploid hybrid rice heterosis utilization. This not only helps the tetraploid rice heterosis exploration and use, but also inaugurates a new technical means for China in the new century "super rice" breeding research. We chose ordinary diploid rice as materials, using colchicine to induce the polyploidization, created the autotetraploid rice three-line materials and identified them. The polyploidization was based on the colchicine-induced callus tissue culture, and we experimented different colchicine concentrations and culture mediums to induce tetraploid plants, confirmed that the optimal concentration for inducement was 500 mg/L, the average induce rate was 25.26 %. Among all the materials, CDR22 and IR26 had higher induced rate; in contrary, 94109 and GANG46B had lower induced rate, the difference was significant. Autotetraploid materials was identified of both morphological and cytological, compared plant height, length of pollen sterility, and other major agronomic traits with a diploid rice as the control plant, identified that the autotetraploid materials had very significant advantages in ear length and thousand-grain weight, as well as the size of the seeds. Cytology identification included observation of the cell morphology, the number of chromosomes, and karyotype analysis on the autotetraploid materials confirmed that their chromosome number was 48, twice of the diploid rice. Mitoses in the three lines were common: chromosomes arrayed normally in metaphase and separated balanced into the two poles, chromosome moved without lagging in anaphase and daughter cells normally formed in telophase except one. It has been proved that tetraploid rice has normal meiosis as their diploid relatives, which usually including series of sub-phases as interphase, prophase I (five sub-phases), prophase II, metaphase I, II, anaphase I, II and telophase I, II. However, abnormal phenomena, such as formation of tetravalent, trivalent and univalent, chromosome lagging and so on, which would finally block meiosis. Configurations of chromosome in metaphaseⅠwere versatile in structure and form accept the bivalent. That condition varied in different strain, suggesting more complex paring configurations and more versatile genetic characters in tetraploid rice. All these abnormalities in meiosis contributed to low fertility of gamete and might consequently resulted in low seed setting. Successive selection and improvement on seed set, productive tiller per plant, total grains per panicle, panicle length and so on had been carried out from 1996 to 2006. The raise of seed sets was significant in both restorers and maintainers. Seed sets of some strains were improved more significantly than others, for example D237（29.70％→72.70％）、DTB（19.55％→53.21％）and et al.. Productive tiller per plant was improved to some extant. The tendency of improvement was rising on the whole but changed in some years such as 1998 and 2002. Part of the stains increased greatly, such as D19B（5.87→13.50）、Dshixiang (7.00→12.00) and so on, but some strains including DTB and Dminghui63 only increased little and decreased in some years by unknown reason. Total grains per panicle increased significantly and all strains except DTB increased. Improvement of panicle length termed to be hard. Different strains showed different capacities for improvement and floating existed in different years for example 2001. It has been proved that other agronomical traits including plant length, flag leaf length and so on could be improved but not significantly by selection also. In a word, agronomical traits could be raised by successive selection that is prerequisite for further utility of autotetraploid rice. Poor fertility is the main barrier for utilizing heterosis between the two rice (Oryza stiva L.) sub-species, indica and japonica. Recently, the development of autotetraploid hybrids (2n=4x=48) has been suggested as a new method for increasing heterosis in hybrid rice. Using standard experimental protocols, the elite diploid rice male sterile, maintainer, and restorer lines were colchine-doubled and autotetraploid counterparts were obtained. Seven resulting hybrids were analyzed for heterobeltiosis (HB), where the F1 was compared to the male parent, and the degree of heterosis, where the F1 was compared to the diploid commercial hybrid, Shanyou 63. The HB among the autotetraploid hybrids ranged from 1.4 to 105.9% for the productive panicles per plant, 0.5 to 74.3% for total kernels per panicle, 17.6 to 255.7% for filled kernels per panicle, and 9.6 to 130.4% for seed set. Improvements in these yield components resulted in the HB for kernel yield ranging from 64.8 to 672.7% among the seven hybrids. Hybrids T461A/T4002 and T461A/T4193 yielded 46.3 and 38.3% more, respectively than Shanyou 63, and all other hybrids but one yielded the same or more than Shanyou 63. The high heterosis for yield suggests that hybrid sterility between two rice sub-species may be overcome by using tetraploid lines followed by intensive selection. Also, the gigantic features of the autotetraploid hybrids may establish a plant structure able to support the higher yield.