Effect of Temperature on Pollen Fertility in Inter-Subspecific Rice Hybrids

Seventeen rice varieties and hybrids of different types (indica, japonica, javanica, indica hybrid, japonica hybrid and inter-subspecific hybrid) were evaluated to determine the effect of temperature on pollen fertility in inter-subspecfic hybrids. The pollen fertility of inter-subspecific hybrids was greatly reduced when average daily temperature dropped to 22.0 - 23.0℃at meiosis stage, and the extent of pollen fertility reduction varied greatly with respect to different hybrids. However, the pollen fertility reduction of indica and japonica hybrids and conventional varieties was not obvious under the same regime of temperature conditions. When the average daily temperature dropped to 20℃, the pollen development of conventional varieties and hybrids was also affected. Correlation analysis revealed that there existed a positive correlation between pollen fertility and average daily temperature. A significant difference (P<0.01) was also found between the two correlation coefficients i.e. inter-subspecific hybrids and conventional varieties. Temperature at meiosis stage of pollen mother cell was a key factor in pollen developing, and the pollen fertility of inter-subspecific hybrids was more sensitive to low temperature than that of traditional variety.     

亚种间杂交水稻协优413开花灌浆特性的比较研究

 以盆栽试验对亚种间杂交水稻协优413、其父本中413和籼型杂交水稻汕优10号的开花灌浆特性进行了比较研究。结果表明中413单穗籽粒总干物重最高，协优413次之，汕优10号最低，分别为4652.5、4173.9和3194.4 mg，结实率中413和协优413相近，分别为80.8%和83.9%，显著高于汕优10号的70.5%。单穗产量的差异与组合(恢复系)的开花灌浆特性有关，即与单穗颖花开花集中程度和强弱势粒灌浆结实的差异程度有关。对于供试的3个品种(或组合)而言，颖花开花越集中，强弱势粒灌浆结实差异越小，产量越高。还对单穗颖花开花历时作为今后亚种间杂交水稻的育种目标进行了讨论。     

常规粳稻在安徽沿江稻区的特征特性研究

以常规粳稻为试验材料,于2010-2015年在安徽沿江稻区的桐城市范岗镇杨安村试验基地,以杂交籼稻、杂交粳稻、常规籼稻为对照,对常规粳稻的特征特性进行了研究。结果表明,常规粳稻具有茎秆矮壮、叶片挺直且短、穗形上翘或直立、穗短且着粒密的植株形态特征和足蘖中穗的经济性状特征;与籼稻相比,常规粳稻表现为感光性强、分蘖率弱,但成穗率高、花时迟,幼穗分化Ⅵ期前后和抽穗扬花期对高温敏感,中后期耐肥等特性。不同播期对常规粳稻经济性状的影响主要表现在单位面积有效穗数和每穗总粒数上,对结实率和千粒重影响较小,常规粳稻随着播期的推迟表现为生物学产量逐渐下降而收获指数逐渐提高。试验结果表明,5月下旬播种、8月底至9月初抽穗的常规粳稻品种为安徽沿江稻区的优势品种,并提出了优势品种的高产栽培技术。     

中熟类型甬优籼粳杂交稻组合产量优势形成及其形态生理特征

以中熟类型甬优籼粳杂交稻组合甬优2640、甬优1640为材料,常规粳稻镇稻11、武运粳30和杂交籼稻丰两优香1号、新两优6380为对照,比较各类型品种在干物质积累、穗部特征、叶片形态及茎秆特性上的差异。结果表明,甬优籼粳杂交稻两年平均产量为11.3 t/hm~2(11.1、11.4 t/hm~2),较常规粳稻和杂交籼稻分别高6.6%和13.0%;产量构成上,甬优籼粳杂交稻的每穗粒数和群体颖花量显著高于对照,有效穗数、结实率和千粒重低于对照;甬优籼粳杂交稻抽穗期、成熟期的干物质量及抽穗至成熟期的干物质积累量依次为13.4 t/hm2、21.6 t/hm~2、6.9 t/hm~2,均显著高于对照;穗部特征上,甬优籼粳杂交稻的单穗质量和着粒密度高于对照,穗长略低于杂交籼稻,近80%的籽粒集中于中上部,而常规粳稻75%的籽粒集中于中下部,杂交籼稻籽粒分布相对匀称;甬优籼粳杂交稻上3叶的叶宽和卷曲率高于对照,叶长和叶基角处于对照之间(以杂交籼稻最大),披垂度最低,上部1、3叶差异显著;株高、穗高、秆长及穗下节间占秆长的比例以杂交籼稻甬优籼粳杂交稻常规粳稻;成熟期单茎茎干质量、单茎鞘干质量及基部节间单位长度干质量以甬优籼粳杂交稻最高。中熟类型甬优籼粳杂交稻组合产量优势特征为足穗基础上,主攻大穗,并保持较高的结实率和千粒重;形态生理特征表现为籽粒集中于中上部,上3叶大小适宜,叶片内卷且直立,株高及穗下节间占秆长的比例适中,成熟期茎秆充实度好。     

Agronomic Performance of F1 Hybrids of Rice (Oryza sativa L.) in Japonica-Indica Crosses

Summary

Generally F₁ hybrids from crosses between japonica and indica rice show variable degrees of sterility. Previous studies revealed that among the indica rice, the Aus type has sexual affinity with japonica cultivars giving higher fertility in F₁ hybrids. Therefore, we made an effort to obtain higher grain yield by producing F₁ hybrids between japonica and Aus-type indica. A field experiment was conducted to investigate the heterosis in these F₁ hybrids for dry matter accumulation, spikelet fertility, yield and yield attributes, to find cross combinations with higher grain yield, and examined the relationships of grain yield with some agronomic characters. F₁ hybrids flowered earlier than their parent cultivars. Heterosis for dry matter accumulation was positive at the panicle initiation stage, at heading and at maturity. The average heterosis for number of panicles, grain and straw yield per plant, number of spikelets per panicle and 1000-grain weight was positive. A few F₁ hybrids showed positive heterosis for number of filled grains per panicle, spikelet fertility and harvest index; but the average heterosis for these traits was negative. Among the yield components, a higher number of panicles per plant and higher number of spikelet per panicle contributed to higher grain yield in F₁ hybrids. A significant and positive relationship existed between spikelet fertility and grain yield per plant. The higher grain yield was attributed to higher dry matter production rather than higher harvest index in F₁ hybrids, although low spikelet fertility limited yield potential in some F₁ hybrids.     

4份籼粳中间型广亲和恢复系的生物学特性及其杂种优势利用

 通过籼粳杂交、广亲和特性鉴定以及育性恢复能力测定等手段,选育出CH58、CH59、C18和C84四个籼粳中间型广亲和恢复系。生物学特性研究结果表明,CH58、CH59、C18和C84的程氏指数分别为11、13、13和15,其中CH58、CH59和C18的籼粳属性为偏籼,C84为偏粳。广亲和特性鉴定和育性恢复能力测定结果表明,四个恢复系具有良好的广亲和性,且都能恢复滇型、BT型、矮败型等粳稻不育系以及野败型、印水型等籼稻不育系的育性,恢复谱广。花时特性研究表明,籼粳中间型广亲和恢复系的开花高峰要明显早于粳稻不育系春江16A。粳不籼恢亚种间杂交稻在单株产量、每穗粒数、二次枝梗数、株高、一次枝梗数和剑叶宽等性状上表现出明显的中亲优势和竞争优势。利用CH58等四个籼粳中间型广亲和恢复系与粳稻不育系配组,已选育出春优58、春优658、春优59、春优618等粳不籼恢亚种间杂交稻,已通过国家、浙江省等品种审定。CH58等四个籼粳中间型广亲和恢复系广亲和性好,恢复谱广,在三系法籼粳亚种间杂种优势利用中具有良好的应用前景。     

Impact of elevated CO2 concentration on inter-subspecific hybrid rice cultivar Liangyoupeijiu under fully open-air field conditions

Hybrid rice cultivar plays an important role in rice production system due to its high yield potential and resistance to environmental stress. Quantification of its responses to rising CO₂ concentration ([CO₂]) will reduce our uncertainty in predicting future food security and assist in development of adaptation strategies. Using free air CO₂ enrichment (FACE), we measured seasonal changes in growth and nitrogen (N) uptake of an inter-subspecific hybrid rice cultivar Liangyoupeijiu grown under two levels of [CO₂] (ambient and elevated by 200 μmol mol⁻¹) and two levels of N fertilization in 2005–2006. Average across the 2 years, FACE increased crop growth rate similarly by 22%, 24% and 23% in the periods from transplanting to panicle initiation (PI), PI to heading and heading to maturity, which was mainly attributed to an increase in green leaf area index rather than the greater net assimilation rate. Grain yield increased greatly under FACE as a result of similar contributions by panicle number per unit area, grain number per panicle and individual grain yield. Final aboveground N acquisition showed a 10.4% increase under FACE, which resulted from enhanced N uptake at both vegetative and reproductive growth stages. Compared with previous FACE studies on final productivity of two inbred japonica cultivars, inter-subspecific hybrid cultivar appears to profit more from elevated [CO₂], which mainly resulted from its greater enhancement in photosynthetic production during reproductive growth due to a lack of N limitations late in the season.     

不同光温反应型配组的籼粳交F1杂种优势的研究

 对早籼／早粳、早籼／中粳、早籼／晚粳、中籼／中粳和中籼／晚粳五种配组方式不完全双列杂交的杂种优势分析表明，株高、剑叶长、主穗长和主穗总粒数等性状的群体平均优势和群体超亲优势较强，Ｆ１性状平均基因型值预测认为，早籼／晚粳和中籼／晚粳杂种株高过高和抽穗偏迟，早籼／早粳配组生育期过短和穗小粒少，综合性状以中籼／中粳和早籼／中粳方式较为优良。Ｆ１性状间显性相关分析表明五种配组方式在株高、抽穗天数、剑叶长、主穗长和主穗总粒数五个性状间均存在显著的正相关，籼粳杂种表现的德大粒多同时伴有植株偏高、抽穗延迟和剑叶过披等倾向，但这种关联性在早籼／早粳或中籼／中粳配组中程度相对较低。     

四川盆地不同类型水稻品种机插栽培的干物质生产及产量特性分析

【目的】阐明机插栽培对不同类型水稻的干物质生产及产量特性的影响,为四川盆地机插秧的推广、品种选育和高产栽培提供依据。【方法】于2012年在四川盆地以中籼中熟杂交稻、中籼迟熟杂交稻、粳稻三类共计10个品种为材料,研究不同类型水稻品种在机插栽培条件下的干物质生产及产量形成特性。【结果】1)三种不同类型品种的水稻移栽后干物质积累均很好地符合Logistic曲线。中籼中熟杂交稻、中籼迟熟杂交稻物质积累均较快,缓增期短,快增期长,物质积累有一定优势;粳稻物质积累速率小,渐增期、缓增期较长,快增期短,物质积累处于劣势。2)三种类型水稻品种相比,在成熟期中籼中熟杂交稻营养器官干物质所占比例最低,生殖器官干物质所占比例最高;中籼迟熟杂交稻成熟期叶片占比最高,而粳稻则是茎鞘比例高、穗比例低。3)中籼中熟杂交稻、中籼迟熟杂交稻的茎鞘、叶片物质输出率和物质转化率均为正值,但粳稻茎鞘物质输出率、转化率和叶片物质转化率均小于0,叶片物质输出率也仅为1.26%。4)中籼中熟杂交稻的产量、每穗实粒数、籽粒充实率、充实度最高,中籼迟熟杂交稻的结实率、千粒重最大,粳稻的有效穗数、成穗率最高,说明籼稻产量主要与穗部性状有关,而粳稻主要与田间有效穗数有关。【结论】在四川盆地的机插栽培条件下,杂交籼稻需提高其有效穗数、成穗率;粳稻需筛选大穗型品种,提高每穗粒数和籽粒充实度。     

水稻籼粳交杂种优势利用研究

水稻籼粳亚种间杂种优势强大,其利用是提高水稻单产的重要途径之一。但杂种F1株高偏高,生育期超亲晚熟,以及结实率偏低,限制了这种优势在生产上的直接利用。针对杂种F1利用上存在三大障碍,本文从育种实践出发,分别提出了相应的解决方案,以期克服籼粳交障碍,充分利用其强大的杂种优势。     

Differences in Response of Grain Yield,Nitrogen Absorption and Utilization to Elevated CO2 Concentration in Different Rice Varieties

【Objective】Our aim is to investigate the differences in response of grain yield, nitrogen absorption and utilization to FACE (atmospheric CO2 concentration increase) of different rice varieties. 【Method】Six rice varieties, including conventional japonica rice, hybrid indica rice, and conventional indica rice, were used to study the effects of free-air CO2 enrichment (FACE) (atmospheric CO2 concentration increase) on the nitrogen absorption, utilization, and yield of different types of rice.【Result】 1) FACE treatment dramatically increased rice yield by 24.17% on average and the maximum increment was observed in conventional indica rice. Compared with other types of rice varieties, hybrid indica showed the highest grain yield under both FACE and control (CK) treatments. 2) Panicle number was significantly improved in FACE treatment with conventional japonica rice varieties having the maximum increment. Spikelet number per panicle was significantly improved in hybrid and conventional indica rice varieties in FACE treatment. 3) The nitrogen absorption (NA) and nitrogen use efficiency for grain yield (NUEg) were significantly higher in FACE treatment than those in CK treatment. The average increase of NA was 21.23% with the maximum increment in hybrid indica rice varieties. Compared with other rice varieties, conventional indica rice varieties had the highest NA both in FACE and CK treatments. The average increase of NUEg was 7.33% with hybrid indica rice varieties enjoying the maximum increment. The hybrid indica rice varieties had the highest NUEg in FACE treatment and in CK treatment, respectively. 4) Nitrogen content was decreased in FACE treatment with the average decrease of 0.105%, among which the maximum decrease was observed in conventional japonica rice. Dry matter weight was extremely and significantly increased in FACE treatment. The average increase of dry weight was 23.95% with the maximum increment in conventional indica rice varieties. NA of single panicle was significantly improved in FACE treatment with the average increase of 10.79% in conventional indica rice varieties and 13.93% in hybrid indica rice varieties, but NA of single panicle was decrease by 9.60% in conventional japonica rice. FACE treatment significantly increased rice NA intensity with an average increase of 22.29% and the maximum increment was observed in hybrid indica rice varieties. The growth duration was not influenced by FACE treatment in all rice varieties. NAs of stem, leaf and panicle were significantly higher in FACE treatment than in CK treatment with the highest increase of 51.86% in leaf. The largest increase of NA was observed in hybrid indica rice. NA in different rice growth stages was significantly improved with the maximum increment of 108.90% during heading-maturity. The maximum increment of NA from heading to maturity was observed in hybrid indica rice varieties.5) Effects of dry matter weight, NA per panicle, NA intensity, NA of panicle and NA from heading to maturity on NA at maturity were greater than those of nitrogen content, panicle number, growth duration, NAA of leaf, stem and sheath, NAA during transplanting-tillering and tillering-heading. 6) Partial productivity of nitrogen fertilizer (PFPN) was significantly improved in FACE treatment with an average increase of 24.16% and the maximum increment in conventional indica rice. NAA per 100 kg grains was significantly reduced in FACE treatment with an average decrease of 4.7%. The maximum decrease of NAA per 100 kg grains was observed in conventional indica rice varieties.【Conclusion】The results indicated that FACE could markedly increased both grain yield and nitrogen use efficiency in all rice varieties, but the increases varied with the variety types.     

水稻亚种间杂种后代Pgi-1同工酶的异常分离

 采用籼稻品种与粳稻品种或偏粳型广亲和性品种的杂交后代F₂集团8个，分析了位于第3染色体上的Pgi-1同工酶的分离情况。其中4个F₂集团表现为显著或极显著偏离正常的孟德尔分离比例，带粳稻标记基因Pgi-1的配子明显减少，只占总受精配子的41.4%±2.8%。而另4个F₂集团则保持正常分离比例。分析结果表明， Pgi-1的异常分离与雌性育性无关，也不是由于花粉形态性败育而致，在第3染色体Pgi-1附近，存在一个独立于ga-2和ga-3的新的配子体基因，控制花粉的受精竞争。在该配子体基因位点上，一些粳稻品种或偏粳型广亲和性品种具有的等位基因可以消除籼粳交后代中由于受精竞争而导致的粳配子败育。     

不同类型籼粳亚种间杂种F1可利用和非可利用杂种优势的评价和利用

 搜集典型籼粳品种、广亲和品种、偏籼或偏粳品系及恢复系并进行杂交。选取25个籼粳亚种间杂种F1，将其划分为5类。以这5类25个组合的生物产量、茎叶重、秆高、出穗期、每穗颖花数、实粒数、结实率等性状为基本资料，分别计算其超亲优势与竞争优势。结果指出：籼粳亚种间杂种F1茎叶重与结实率存在负相关，杂种优势含可利用与非可利用两部分，典型籼粳F1杂种优势是难以利用的，利用广亲和系与偏籼或偏粳恢复系及其派生系或者偏籼广亲和系和偏粳广亲和系配组，实现部分利用亚种间杂种优势，应作为当前亚种间杂种优势利用育种战略的重要措施。     

甬优系列杂交水稻SSR标记指纹图谱和籼粳属性

用22个SSR分子标记对13份甬优系列杂交水稻组合及其亲本材料和6份籼粳对照种进行分析,共获得87个等位基因,每对引物扩增的等位基因数为2~8个。所有供试材料间均检测到了差异,从而建立起甬优1号~甬优6号杂交水稻组合及其亲本的DNA指纹图谱。聚类分析结果表明,9份供试材料与3份粳稻对照种聚于一类,属粳稻;4份供试材料与籼稻对照种IR36聚于一类,属籼稻。这与形态分类结果基本一致。从分子水平确认了杂交水稻甬优6号和甬优4号为籼粳亚种间杂交稻。     

两系法杂交稻两优培九结实率稳定性及其与温度的关系

分析了1999~2000年中国南方稻区19个区域试验点和5个生产试验点两优培九的结实率和产量。与汕优63相比,两优培九结实率要低4.3~7.5个百分点,但变异系数相近;产量水平及其变异系数则相近。在南京（32[sup]。[/sup]3′N, 118[sup]。[/sup]48′E）5月5~25日播种,两优培九在9月4日之前齐穗,结实率为75%~90%,产量在1 kg/m2以上;播种期推迟至6月14~15日,出穗期将延迟至9月17~21日,结实率比适宜播期的结实率低10~15个百分点。开花受精期5 d日均温平均值在13.7~28.5℃范围内,温度每增加1℃,受精率提高1.9%~10.7%。花粉育性与始花前5 d日均温平均值呈极显著的二次多项式相关。抽穗期适宜日均温（受精率≥90%）和安全日均温（受精率≥75%）分别为26.5℃和22.9℃。结果显示,北纬34[sup]。[/sup]以南地区为两优培九适宜种植区,宜将开花期安排在日均温为26~28℃的时期。     

温度对亚种间杂种花粉育性的影响

以17个不同类型的籼、粳、爪哇型品种及其杂种为材料,通过分期播种,研究了温度变化对花粉育性的影响。结果表明,当花粉母细胞减数分裂期的日平均气温低于22~23℃时,亚种间杂种的花粉育性显著降低,不同组合花粉育性存在明显差异,而品种间杂种和常规品种的花粉育性受影响较小;当花粉母细胞减数分裂期的日平均气温低于20℃时,常规品种和品种间杂种的花粉发育也受到不同程度的影响,不同品种与组合间存在差异。花粉母细胞减数分裂期的日平均温度与花粉育性的相关性分析表明,温度与花粉育性呈显著正相关,亚种间杂种与常规品种的相关系数存在极显著差异。说明减数分裂期的花粉育性受温度影响,温度对亚种间杂种花粉育性的影响较常规品种大。关键词     

滇型杂交粳稻主要亲本的SSR 指纹图谱及其遗传差异分析

用筛选的13对SSR引物,构建了41个水稻品种(包括35份滇型杂交粳稻恢复系、保持系材料、2个杂交种以及4个籼稻品系)的分子指纹图谱.聚类分析表明,41个水稻品种间遗传相似系数在0.52～0.94之间;在相似系数0.52处,可以将粳稻与籼稻区分开;在相似系数0.66处,可将杂交粳稻与其它粳稻品系区分开;在相似系数0.71处,又可将大部分恢复系与保持系区分开.生产中应用的一些强优势滇型杂交粳稻的亲本分别聚于不同的类群,表明亲本间的遗传差异较大.     

水稻光温敏核不育系的光温特性及其熟期性模型研究

对8个熟期性不同的水稻光温敏核不育系在三亚、贵阳、武汉、南京4地各4 a的分期播种熟期性资料及同期的温度和日长资料进行了分析.结果表明,不同熟期类型不育系的感光性和感温性强弱均为晚籼(粳)＞中籼＞早籼;大部分不育系在中温条件(24～28℃)下的感光性强于在低、高温条件下的感光性;各不育系短日下的感温级低于或等于长日下的感温级;短日高温生育期的表现与常规水稻一致,即中籼＞早籼＞晚籼(粳).选配了各不育系的熟期性模型,早籼和中籼不育系可以用温度线性或非线性模型表达,但晚籼(粳)不育系以用光温综合模型表达为宜.     

Research Progress on Heat Stress of Rice at Flowering Stage

Global warming has caused frequent occurrence of heat stress at the flowering stage of single-season rice in the Yangtze River region of China, which results in declines of spikelet fertility and yield in rice. Rice flowering stage is the most sensitive period to high temperatures, and therefore, the key for heat stress happening is the flowering stage coinciding with high temperature, which causes spikelet fertility decreasing in heat-sensitive varieties, and is the major factor for heat injury differences among various rice planting regions. With the development of rice breeding, temperature indexes for heat stress has been converted from daily maximum temperature of 35 °C to 38 °C with the stress duration of more than 3 d. During the flowering stage, anther dehiscence inhibition and low pollen shedding onto the stigma are two main reasons for spikelet fertility reduction under high temperatures. At panicle initiation stage, high temperatures aggravate spikelet degeneration, and destroy floral organ development. Various types of rice varieties coexist in production, and indica-japonica hybrid rice demonstrates the highest heat resistance in general, followed by indica and japonica rice varieties. In production, avoiding high temperature is the main strategy of preventing heat stress, and planting suitable cultivars and adjustment of sowing date are the most effective measures. Irrigation is an effective real-time cultivation measure to decline the canopy temperature during the rice flowering stage. We suggested that further study should be focused on exploring heat injury differences among different rice variety types, and innovating rice-planting methods according to planting system changes in rice planting regions with extreme heat stress. Meanwhile, high temperature monitor and warning systems should be improved to achieve optimal heat stress management efficiencies.     

长江中下游稻区双季晚粳稻产量生理与资源利用效率研究进展

长江中下游稻区是我国水稻主产区,同时又是单、双季稻混作区。目前,随着经济发展和人民生活水平的提高,人们对优质大米,尤其是优质粳米的需求日益增加,因此,在双季稻生产中引入粳稻具有重要的现实意义。本文介绍了长江中下游双季稻的温光资源特性,总结了现有双季晚(籼/粳)稻品种的种植表现,从产量、产量结构、干物质积累、群体动态、生育期、温光利用率、稻米品质等方面比较了长江中下游稻区晚粳与晚籼的可能差异。总体来说,双季晚粳在产量、每穗粒数、结实率、千粒重等方面均显著高于晚籼;前期干物质积累两者无显著差异,但是后期干物质积累量晚粳要高于晚籼,晚粳的灌浆率显著高于晚籼,这预示着双季晚粳具有更高的产量潜力。粳稻比籼稻有着较平稳的茎蘖动态,这使其具有更强的后期光合能力、更高的后期光能利用率;全生育期晚粳比晚籼长,主要体现在推迟抽穗结实,延长结实灌浆期;粳稻全生育期积温和光照时数均显著高于籼稻,粳稻后期叶面积指数大于籼稻,光合势亦高于籼稻,而在生育前期(拔节至抽穗期)两者对温光资源的利用基本相当,因此温光利用率晚粳显著高于晚籼;另外,晚粳的稻米品质要优于晚籼。因此,相对于双季晚籼,双季晚粳具有更高的应用推广价值。