Plant Ideotype at Heading for Super High-Yielding Rice in Double-Cropping System in South China

The newly released super high-yielding hybrid rice combinations, Yueza 122, Fengyou 428, Peiza 67, and the super high-yielding conventional cultivars, Guangchao 3 and Shengtai 1, were grown in both early and late seasons. The morphological characters of each population were investigated at the heading stage, and the data were analyzed by using ANOVY and other statistic methods. The plant ideal morphological characters at the heading stage were established as follows： 1 ） for the early-season cropping, 90-105 cm plant height; 11-12 tillers per plant; 35-40 em length and 2.1-2.2 cm width of flag leaf; 46-50 cm length and 1.8-2.1 cm width of the second leaf from the top （L2）; 59-64 cm length and 1.4-1.9 cm width of the third leaf from the top （L3）; 7°-14°, 18° and 200-33° for the ideal leaf angles of the flag leaf, L2 and L3, respectively; 2） for the late-season cropping, 90-100 cm plant height; 9-15 tillers per plant; 30-41 cm length and 1.8-2.0 cm width of flag leaf; 53-61 cm length and 1.3-1.8 cm width of L2; 52-58 cm length and 1.2-1.5 cm width of L3; 9°-19°, 15°-37° and 16°-49° for the ideal leaf angles of the flag leaf, L2 and L3, respectively. The main physiological characteristics of these varieties were also analyzed.

Changes in Some Physiological Characteristics After Full Heading Stage in Flag Leaves of Super High-Yielding Inbred Rice

In a field experiment, rice cultivar Shanyou 63 was used as a check cultivar to investigate the changes in activity of peroxidase and contents of malondialdehyde and soluble protein after full heading stage in flag leaves of two super high-yielding inbred rice, including Shengtai 1 and Yuxiangyouzhan. The results showed that the peroxidase activities and soluble protein contents in the leaves of the three cultivars tended to increase gradually to peak values and thereafter descended during stage after full heading. Moreover, both the peroxidase activities and soluble protein contents of Shengtai 1 and Yuxiangyouzhan peaked at 8 days after full heading, which was compared with that of Shanyou 63 at 4 days later. Meanwhile, the malondialdehyde contents in the leaves of the three cultivars increased gradually after full heading stage. In addition, activities of peroxidase and contents of malondialdehyde and soluble protein in different cultivars were various at the same time. In general, for Shengtai 1 and Yuxiangyouzhan, the peroxidase activities and soluble protein contents were higher than those of Shanyou 63, whereas the malondialdehyde contents were lower compared with that of Shanyou 63. And these features could make the senescence of leaf become later and slower and photosynthetic product was more in Shengtai 1 and Yuxiangyouzhan than that in Shanyou 63.

Effects of Plant Density and Nitrogen Application Rate on Grain Yield and Nitrogen Uptake of Super Hybrid Rice

The nitrogen uptake, yield and its components for two super-high-yielding hybrid rice combinations, Guodao 6 and Eryou 7954 were investigated under different plant densities （15, 18, and 21 plants/m^2） and different nitrogen application rates （120, 150, 180, and 210 kg/hm^2）. The experiment was conducted on loam soil during 2004-2006 at the experimental farm of the China National Rice Research Institute in Hangzhou, China. In these years, the two hybrid rice cleady showed higher yield at a plant density of 15 plants/m^2 with a nitrogen application rate of 180 kg/hm^2. Guodao 6 produced an average grain yield of 10 215.6 kg/hm^2 across the three years, while the yield of Eryou 7954 was 9 633.0 kg/hm^2. With fewer plants per unit-area and larger plants in the plots, the two hybrid rice produced more panicles per plant in three years. The highest nitrogen uptake of the two hybrid rice was at a plant density of 15 plants/m^2 with a nitrogen application rate of 180 kg/hm^2. Further increasing nitrogen application rate was not advantageous for nitrogen uptake in super-high-yielding rice under the same plant density.

Relationship between leaf photosynthetic function at grain filling stage and yield in super high-yielding hybrid rice (Oryza sativa.L)

The characteristics of dry matter production before and after heading and tne relationships between photosynthesis of flag leaves and dry matter accumulation in panicles were investigated on super high-yielding rice cv. Xieyou 9308 (the yield of up to 12 t/ha) with rice cv. Xieyou 63 as a control. The results showed that (i) the capacity of dry matter production before and after heading in Xieyou 9308, i.e. biomass and daily dry matter production, was remarkably higher than that in Xieyou 63, especially after heading; (ii) CO2 assimilation capacity in flag leaves in Xieyou 9308, namely Leaf Source Capacity (LSC), was also significantly higher than that in Xieyou 63, and the supply of photosynthate in leaves and the demand of grain filling were completely synchronous in Xieyou 9308, but photosynthetic function in flag leaves in Xieyou 63 declined sharply 20 days after heading and it was not enough to meet the demand of grain filling. These results confirmed that high efficient photosynthetic function in leaves after heading and its complete synchronization with grain filling are the key approaches to super high yield of rice.

CLIMATIC RISK ZONING OF DOUBLE CROPPING SUPER RICE CULTIVATION IN HUNAN PROVINCE

Based on meteorological data including daily sunshine duration, temperature and precipitation from 97 meteorological stations in Hunan province during the period of 1981—2010, in combination with the field experiment in different places at different sowing dates, the precise climatic risk zoning of double cropping super rice cultivation has been studied by using the spatial interpolation method and other Geographical Information System(GIS)technologies. Three key climatic factors were selected including chilling in May, high temperature heat damage during July to early August and low temperature damage in autumn in this study. Furthermore, based on the analysis of climatic conditions suitable for double cropping super rice cultivation and climatic disasters, 8-22 ℃ active accumulated temperature, sunshine duration from late March to October, climatic risk index of the low temperature in autumn, and climatic risk index of chilling in May were selected as key climatic factors to study the precise agro-meteorological regionalization of double cropping super rice in Hunan province. The results showed that: the high-yielding zones of double cropping super rice in Hunan were mainly located in Zhuzhou, Hengyang, Yongzhou and Chenzhou City, the moderate-yielding zones were primarily located in the east and north reaches of Dongting Lake,together with most of Changsha, Zhuzhou and Xiangtan City, and other regions in Hunan were not suitable for double cropping super rice. These findings can provide valuable information for the large-scale cultivation of double cropping super rice in Hunan province.

Breeding of New Japonica-indica Hybrid Rice Combination Chunyou 284

Chunyou 284 is a medium- japonica hybrid combination,as well as an indica-japonica subspecific hyrbid with super-high yield,which was developed from Chunjiang 23A,a thermo-sensitive CMS line with very early anthesis time,and C84,an indica-japonica intermediate type restorer line with wide compatibility.This combination has the advantages of high yield potential,early maturity,excellent comprehensive agronomic traits and wide adaptability.It was approved by Jiangsu Provincial Crop Variety Approval Committee in June,2018.The breeding process,main characteristics,cultivation techniques and seed production points of the combination were introduced.

Proteomic Analysis of the Response of Liangyoupeijiu(Super High-Yield Hybrid Rice) Seedlings to Cold Stress

Liangyoupeijiu is a super high-yield hybrid rice. Despite its advantages with respect to yield and grain quality, it is sensitive to cold, which keeps it from being widely cultivated. We subjected Liangyoupeijiu seedlings to 4 ℃ cold treatment, then extracted the leaf proteins. After 2-D gel electrophoresis separation and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis, a series of differentially displayed proteins were identified. Some metabolism-associated proteins were found among the downregulated proteins, such as carbamoyl phosphate synthetase, transketolase 1, dihydrolipoamide dehydrogenase and glyceraldehyde 3-phosphate dehydrogenase. The upregulated proteins included both stress-resistance proteins such as nucleoside diphosphate kinase I and proteins that are negative for rice growth, such as FtsH-like protein, plastid fusion and/or translocation factor （Pftf） and actin. Our results indicate that cold may inhibit Liangyoupeijiu growth through decreasing metabolic activity and damaging cell structure.

杂交粳稻13.5t hm^-2超高产群体动态特征及形成机制的探讨

选用杂交粳稻甬优8号,以国家粮食丰产工程兴化、姜堰实施基地1.0hm2连片与6.67hm2连片超高产攻关方为依托,研究了13.5thm-2超高产群体特征,并探讨了群体形成机制。结果表明,较之12.0thm-2左右群体,13.5thm-2群体的穗型大,群体颖花量多(60000×104hm-2以上),有效穗数、结实率和千粒重与之相当;群体茎蘖于生育前期稳步增长,至有效分蘖临界叶龄期达适宜穗数,高峰苗出现在拔节期,数量少,为预期穗数的1.3倍左右,此后群体平缓下降,至抽穗期达适宜穗数,成穗率高(>75%);群体叶面积指数前期增长相对较缓慢,最大值出现在孕穗期,为8.5左右,此后下降缓慢,成熟期仍保持在4.0以上;群体光合势生育前期较小,中、后期较大,总光合势为675×104m2dhm-2以上,抽穗至成熟期的光合势占总光合势的45.0%以上;群体拔节前干物质积累速度相对较缓、积累量略低,拔节后积累速度较快,至抽穗期群体生物量为13.5thm-2以上,抽穗后积累量亦高,一般为9.75thm-2以上,总干物重高达23.25thm-2以上。13.5thm-2超高产群体形成机制为,依靠精苗,发大蘖,及时够苗,提高够苗期群体质量(有效分蘖临界叶龄期),为中期高质量群体结构的培育奠定生物学基础;依靠合理的群体动态及其规模,培育适宜数量的壮秆大穗,于抽穗期形成具有强抗倒力和巨量安全库容的高光效群体;依靠平稳消退的光合系统,提高抽穗后群体光合物质生产力,增大群体库容的总充实量,并维持较大的茎鞘强度,增强群体的安全抗倒力。

不同栽培模式早稻-再生稻头季稻分蘖动态及生理生化特性研究

试验研究超高产栽培模式和常规栽培模式对再生稻头季稻分蘖动态及生理生化特性影响的结果表明，与常规栽培模式相比，头季生育期间，超高产栽培模式稻株的根系活力、叶绿素含量、叶面积指数、硝酸还原酶活性、硝态氮含量、Ca^2＋-ATPase和Mg^2＋-ATPase活性从分蘖期到成熟期分别高出20．60％～38．65％、5．16％～23．26％、18．91％～63．29％、18．22％～76．76％、34．88％～48．35％、1．25％～17．94％和4．09％～17．87％，有效分蘖期缩短5d，低节位分蘖多51．61％；不同生育期超高产栽培模式氮素累积量是常规栽培模式的1．43～2．44倍，磷素累积量是常规栽培模式的1．21～1．48倍，孕穗期后的钾素累积量是常规栽培模式的1．55—2．21倍，为优化群体质量，提高后期群体光合效率，实现高产奠定了基础。

不同栽培模式早稻-再生稻头季干物质积累运转特性研究

试验研究不同栽培模式（超高产栽培模式和常规栽培模式）对再生稻头季稻株叶绿素含量、叶面积指数、干物质积累运转及产量构成的影响结果表明，秧苗移栽大田后，超高产栽培模式头季稻株的叶绿素含量和叶面积指数从分蘖期到成熟期均比常规栽培模式的高，在生长中、后期尤其显著，分别高10．77％和63．29％；超高产栽培模式的群体干物质累积总量在头季稻整个生育期比常规栽培模式高24．83％-38．17％，茎鞘物质运转率、茎鞘物质转换率分别比常规栽培模式高10．60％和13．88％，单位面积有效穗数比常规栽培模式多21．43％，穗粒数多1．88％，产量比常规栽培模式高24．22％。

江西绿肥-双季稻超高产种植模式与调控技术研究——Ⅰ.不同移栽方式对早稻生长发育及产量的影响

对2005年早稻的不同移栽方式进行了比较研究,揭示并阐明了抛秧早稻的生态生理特征如下:秧苗带土抛秧不伤根,返青快,促进了水稻分蘖的早生快发,以及有效穗的形成;抛秧水稻的单株叶面积要低于手插稻,但是群体的叶面积指数高,提高了水稻群体的光合速率;抛秧稻的根数、根重、根系活力都要比手插稻的显著要高,为水稻的灌浆结实积累了大量的物质。抛秧稻最终获得超高产的有效途径是在有效穗,穗粒数提高的前提下,保证结实率不下降。

麦-稻两熟超高产的土壤养分平衡与调控研究

以兴化市钓鱼乡为例，研究了麦－稻两熟超高产的土壤有机质、养分的动态平衡以及调控途径。结果表明，在不同的管理模式下，超高产农田有机物归还量比高产条件下高１４．２２％～１８．６９％。超高产条件下氮、磷盈余量、钾亏缺量分别为３８０．０～４３２ｋｇ／ｈｍ２、１９．１５～３２．７８ｋｇ／ｈｍ２、９９．１～１７４．０ｋｇ／ｈｍ２，与高产条件下比较氮、磷盈余量提高，而钾的亏缺量相近。提出了改善超高产农田土壤肥力的主要措施。

Hybrid rice achievements, development and prospect in China

This article reviews the history and progress of hybrid rice development. Hybrid rice research was initiated back in 1964, and commercialized in 1976. Three-line and two-line system hybrid rice were developed in 1974 and 1995, respectively. Research on super hybrid rice, which was first launched by Ministry of Agriculture, China in 1996, is discussed, and the great progress of super hybrid rice had been achieved with a new yield record by 15.4 t ha^-1 in the 6.84 ha demonstration location in Xupu, Hunan Province, China in 2014. And the mechanism of heterosis, the techniques of hybrid seed production and the modern field managements in hybrid rice over the past decades are also discussed. Additionally, this article dealt with the intellectual property protection（IPR） and development of hybrid rice seed industry in China. Major factors that constrain hybrid rice development are analyzed and possible solutions to this problems are proposed. Finally, the authors present methods to further increase production yield, and propose an improvement for breeding super high-yielding hybrid rice based on these methods.

Experimental and genomic evidence for the indica-type cytoplasmic effect in Oryza sativa L.ssp.japonica

Cytoplasmic effects are important agronomical phenomena that have generated widespread interest in both theory and application. In the present study, five high yield rice cultivars（Oryza sativa L. ssp. japonica） in large-scale cultivation in northeast China were determined to possess Oryza sativa L. ssp. indica-type cytoplasm using cytoplasmic subspecies-specific molecular markers. This was confirmed by cytoplasmic genome-wide single nucleotide polymorphisms（SNPs） and functional gene sequencing. Two of these five japonica cultivars were core breeding parents with high yield and the other three were super-high-yield varieties registered by the Ministry of Agriculture of China. We constructed nuclear substitution lines to further demonstrate whether and how this indica-type cytoplasm contributed to yield improvement by comparing yield components. The results showed that under the same japonica nuclear background, the lines with indica-type cytoplasm had a significant decrease in tillers in exchange for increased grain number per panicle compared with their recurrent parents. Our results implied that botanical basis of this cytoplasmic effect was to reduce the plant＇s branching differentiation to produce more floral organs under the constant nutrition. Our findings open another door for the utilization of inter-subspecific hybridization for the improvement of rice cultivar.

南粳系列超级稻品种灌浆期光合产物的分配特性

【目的】研究南粳系列超级稻灌浆期光合产物转运和分配及相关基因表达量的变化特性及其与对照品种的差异,总结南粳系列超级稻高产的生理优势,为优质高产粳稻的培育提供理论依据。【方法】采用南粳5718、南粳晶谷、南粳3908和南粳5055为研究对象,以淮稻5号为对照,在孕穗期、开花期以及开花后每隔7 d至成熟期测定剑叶光合速率、地上部干物质分配和转运,以及剑叶和籽粒发育不同时期物质转运相关基因的表达量,统计产量差异。【结果】南粳系列超级稻产量和千粒重高于淮稻5号,其剑叶净光合速率在孕穗期和花后28 d显著高于淮稻5号。在物质转运方面,南粳系列超级稻开花后茎叶干重、叶片输出量、输出率和转运率显著高于淮稻5号,其中南粳5718叶片输出量和输出率最高。南粳5718剑叶中与淀粉降解和糖类代谢相关基因(OsSPS1,OsSUT2,OsGWD1)的表达比其他品种启动早,最高表达量也高于其他品种。籽粒中SWEET基因在灌浆早期的蔗糖转运过程中扮演重要角色,中后期OsPK3、OsSUT1、OsSUT2基因在糖类的运输卸载中发挥重要作用,OsAGPL2和OsDPE1基因在中后期淀粉合成中发挥重要作用,南粳5718、南粳晶谷、南粳3908籽粒中与淀粉合成和糖类运输的相关基因在不同时期的表达量显著高于淮稻5号。【结论】南粳系列超级稻较高的产量在物质转运方面主要有以下特征:茎秆和叶片物质积累量多,穗积累量大,叶片和茎秆物质转运率高;叶片中蔗糖代谢和转运相关基因表达量高,有利于蔗糖在源端的合成、装载和转运;籽粒中蔗糖转运和淀粉合成相关基因表达量高,有利于蔗糖在库端的卸载及籽粒中淀粉的合成。

水稻小粒不育系新组合卓两优1126的高产特征

[目的]挖掘杂交水稻产量潜力,培育超高产品种,既是一道科学难题,也是“藏粮于技”安全战略。本研究旨在解析小粒不育系卓201S配组的杂交稻卓两优1126高产形成规律,为优质高效超级杂交稻培育提供理论支撑。[方法]2022年选用小粒不育系新组合卓两优1126和对照品种超级稻两优培九、Y两优900和湘两优900为试验材料,在湖南省隆回县统一高产栽培,系统比较卓两优1126与其他3个超级杂交稻产量及其产量构成、干物质积累、根系发育和抗倒性,探究小粒不育系新组合卓两优1126高产特征。[结果]卓两优1126产量极显著高于对照,较超级杂交稻第1期代表品种两优培九增产35.07%,较超级杂交稻第4期代表品种Y两优900增产17.84%,较超级杂交稻新代表品种湘两优900增产14.52%。卓两优1126产量的提高主要原因是在保持稳定千粒重和结实率基础上,通过平衡有效穗数与每穗粒数使群体总颖花数显著提升。与对照相比,卓两优1126单茎地上部干质量、根干质量和根冠比均极显著高于对照,表明卓两优1126根系具有显著的生长优势,能够很好地协调植株地下和地上部分的生长,有助于超高产的形成。卓两优1126株高适中,基部3节间总长和穗下节间长度都极显著高于对照,但基部第2节间的弯曲力矩和抗折力与湘两优900的差异未达到显著水平,卓两优1126在增加株高的同时保持了较强的抗倒性。卓两优1126耐低氮,稻米品质综合评级为部标优质2级,极端高温下较对照Y两优1928增产5.53%。[结论]卓两优1126在保持稳定的千粒重和结实率基础上,通过平衡有效穗数与每穗粒数使群体总颖花数显著提升,从而实现超高产。卓两优1126亲本间粒型存在显著差异,可以实现父母本混播混收的全程机械化制种,降低种子生产成本。另外,小粒型不育系千粒重仅为常规不育系的1/2,在制种产量保持不变的前提下,单位制种面积的杂交稻种子粒数比普通不育系多1倍,大幅降低杂交稻的用种成本。因此,以卓两优1126为代表的“小粒种高产稻”模式,能为解决杂交水稻当前困境提供新思路,是新的发展方向。

超高产常规粳稻宁粳1号和宁粳3号群体特征及对氮的响应

2007—2008年对宁粳1号和宁粳3号的丰产示范方进行调查,2008年以宁粳3号为材料进行氮肥用量和前后比例试验,研究常规粳型超级稻超高产群体特征及对氮的响应。结果表明,常规粳型超级稻宁粳1号和宁粳3号抽穗后干物质积累占籽粒产量的70%～80%,茎叶等营养器官的表观转运率少,易高产稳产。足够的颖花量是高产稳产的保证,要达到11.0thm?2以上的产量,颖花数要≥42000m?2;要达到11.7thm-2以上的产量,颖花数要≥45000m-2,同时结实率≥90%,粒重≥26mg。超高产群体抽穗期适宜叶面积指数(LAI)为7.0～7.5,叶色呈"黑黄"节奏变化,后期生长速率(CGR)高,收获指数(HI)≥0.5。氮肥的适量施用和适当后移,不仅可以保证宁粳1号和宁粳3号生育期"黑黄"节奏变化,建立抽穗期适宜LAI的群体,还可以保持超高产株型特征,提高抽穗后LAI、叶面积维持期、CGR和HI,最终实现超高产量。

水稻新株型创造与超高产育种(英文)

水稻单产水平在经历了矮化育种和杂种优势利用两次大的飞跃后 ,已有相当长一段时间停滞不前。第三次产量突破将产生于理想株型与优势利用相结合的超高产育种。研究结果表明 ,增加生物产量是获得超高产的物质基础 ,优化产量结构是实现超高产的先决条件 ,利用籼粳稻亚种间杂交或地理远缘杂交创造新株型和强优势 ,再通过复交或回交优化性状组配是选育超高产品种的有效途径。根据这一理论与方法 ,中国北方已经创造出新株型优异种质 ,并育成了直立大穗型超高产粳稻新品种 ,在北方寒地稻作生态区产量已达到 12～ 13t· ha-1。这些品种的最大特点是直立或半直立大穗型 ,生物产量高。从光合作用与物质生产角度看 。

超高产水稻的产量构成和库源结构

为探讨水稻超高产育种和栽培调控的主攻方向，分析比较了不同时期主栽品种和杂交稻组合不同产量水平的产量构成和库源结构。试验结果表明，超高产水稻产量构成特征是具有足够的穗数和大穗；超高产育种的方向是稳定穗数，培育大穗，增加单位面积总粒数，并增强后期物质生产能力；超高产栽培应利用超高产品种的大穗优势，首先确保适应当地生态的足额的穗数，建立足穗大穗的巨库群体。文中就增加库容量和物质生产能力问题作了讨论。

水稻“精苗稳前、控蘖优中、大穗强后”超高产定量化栽培模式

【目的】寻求水稻稳定超高产的栽培模式。【方法】以早熟晚粳品种武粳15、常优1号为供试材料,其它栽培措施统一在最佳技术指标前提下,就氮肥运筹与穗肥施用叶龄期,设置了稳前优中强后、平衡促进和促前控中3种栽培模式,并以长江中下游地区单季稻大面积生产上的常规栽培模式为CK,对产量及其结构、群体生长发育动态以及根系活力等方面进行系统比较。同时,在江苏东海、兴化、高邮、常熟等地,以徐稻3号、常优1号、陵香优18、武粳15等品种为材料,进行(15—50)×667m2连片的稳前优中强后超高产栽培综合试验与扩大到100×667m2连片试验田上的生产性验证试验。【结果】2品种稳前优中强后、平衡促进2模式的实产均达到了超高产水平(≥750kg/667m2)。与CK相比,稳前优中强后、平衡促进2模式每穗粒数多、群体颖花量大,单位面积穗数、结实率和千粒重则与之相当;2模式的群体于有效分蘖临界叶龄期准时够苗,高峰苗出现在拔节期,且数量适中(适宜穗数的1.3—1.4倍),此后群体平缓消减,至抽穗期基本稳定,最终成穗率显著高于CK;其群体LAI动态与茎蘖动态趋势基本一致,最大LAI均出现在孕穗期,为8.0—8.5,成熟期仍保持3.5—4.0;群体光合势与干物质积累,2模式在生育前期(移栽—拔节期)较CK低,中期(拔节—抽穗期)与CK相当,后期(抽穗—成熟期)显著高于CK;2模式在拔节期的根系干重与CK相当,抽穗期和成熟期则显著高于CK,而这3个时期的根冠比均显著高于CK,其抽穗后(抽穗—腊熟期)的根系平均伤流量与颖花根流量均显著高于CK。同时,连续2年多地的稳前优中强后超高产综合栽培试验以及后3年扩大到100×667m2连片试验田上的生产性验证试验,实产均达800kg/667m2左右。【结论】揭示了水稻超高产栽培的根本在于"强支撑、扩库容、促充实";提出了水稻精苗稳前、控蘖优中、大穗强后的超高产定量化栽培模式。