Yield potential and nitrogen use efficiency of China's super rice

In 1996, a mega project that aimed to develop rice varieties with super-high yield potential(super rice) was launched by the Ministry of Agriculture(MOA) in China using a combination of the ideotype approach and intersubspecific heterosis. Significant progress has been made in the last two decades, with a large number of super rice varieties being approved by the MOA and the national average grain yield being increased from 6.21 t ha~(-1) in 1996 to 6.89 t ha~(-1) in 2015. The increase in yield potential of super rice was mainly due to the larger sink size which resulted from larger panicles. Moreover, higher photosynthetic capacity and improved root physiological traits before heading contributed to the increase in sink size. However, the poor grain filling of the later-flowering inferior spikelets and the quickly decreased root activity of super rice during grain filling period restrict the achievement of high yield potential of super rice. Furthermore, it is widely accepted that the high yield potential of super rice requires a large amount of N fertilizer input, which has resulted in an increase in N consumption and a decrease in nitrogen use efficiency(NUE), although it remains unclear whether super rice per se is responsible for the latter. In the present paper, we review the history and success of China's Super Rice Breeding Program, summarize the advances in agronomic and physiological mechanisms underlying the high yield potential of super rice, and examine NUE differences between super rice and ordinary rice varieties. We also provide a brief introduction to the Green Super Rice Project, which aims to diversify breeding targets beyond yield improvement alone to address global concerns around resource use and environmental change. It is hoped that this review will facilitate further improvement of rice production into the future.     

Advances and Prospects in Breeding Japonica Rice for Super High Yield in the Northern China

In this paper, advances and prospects in breeding japonica rice for super high yield in the northern China were analyzed comprehensively in terms of breeding theories, techniques and practices. The author holds that developing and spreading super rice is an important way to enhance the overall yielding ability of japonica rice and attaining immense expansion of rice production. After theories and technical guidelines for super rice breeding were formulated, which involved the creation of new plant morphology and strong hybrid vigor through crossing indica with japonica subspecies, the optimization of combination of desirable traits via multiple crossing or backcrossing, the assemblage of favorable genes and the integration of ideal plant morphology with the utilization of vigor-major breakthroughs have been made in conventional breeding of japonica super rice. A batch of new super rice varieties marked by superior rice quality and high disease resistance, such as Shennong 265, Shennong 606, and Jijing 88, etc., have been developed and released. In comparison with the advancement in conventional breeding ef super rice, progress in hybrid japonica super rice breeding is slower because of climatic and ecological constraint in northern China. Therefore, solving the contradictions between vigor and growth duration, between yield and rice quality, and boosting vastly seed production are still serious challenges for breeders of hybrid japonica rice. Physiological and genetic problems in japonica super rice breeding are also discussed in this paper.     

Relationship Between Grain Yield and Yield Components in Super Hybrid Rice

Chinese super hybrid rice breeding project has developed many new varieties with great yield potential.It is controversial which yield component should be emphasized in super hybrid rice production.The present study was conducted to compare super hybrid rice with common hybrid and super inbred rice and analyze contributions of yield components to grain yield of super hybrid rice under experimental conditions,and evaluate relationships between grain yield and yield components of super hybrid rice in farmer's paddy fields.Field experiments were done in Changsha,Guidong,and Nanxian,Hunan Province,China,from 2007 to 2009.Eight super hybrid varieties,one common hybrid variety,and one super inbred variety were grown in each location and year.Rice production investigation was undertaken in high-yielding (Guidong),moderate-yielding (Nanxian),and low-yielding (Ningxiang) regions of Hunan Province,China,in 2009.Grain yield and yield components were measured in both the field experiments and rice production investigation.Super hybrid rice varieties outyielded common hybrid and super inbred varieties across three locations and years.Yield potential has been increased by 11.4％ in super hybrid rice varieties compared with common and super inbred varieties.The higher yield of super hybrid varieties was attributed to improvement in panicle size.Panicles per m2 had the highest positive contribution to grain yield with the exception under yield level of 10.0 to 12.0 t ha-1,and was positively related to grain yield in farmer's field at all of the high-,moderate-,and low-yielding regions.Our study suggests that panicle per m2 ought to be emphasized in super hybrid rice production.     

北方粳型稻超高产育种理论与实践

 从育种理论、育种技术及育种实践等方面，综合评述了中国北方粳型稻超高产育种研究进展与前景，认为培育和推广超级稻是继株型育种和杂交稻之后，提高北方粳稻综合生产能力，实现北方水稻生产跨越式发展的重要途径。在“利用籼粳稻杂交创造新株型和强优势，通过复交优化性状组配，聚合有利基因，选育理想株型与优势利用相结合的超级稻”育种理论与技术路线确立之后，北方粳型超级粳稻在常规育种方面已取得重大突破，成功地培育出一批优质抗病的超级稻新品种并已广泛应用于生产，如沈农265、沈农606、吉粳88等。与常规超级稻育种相比，超级杂交粳稻育种研究进展则相对较缓慢。这一方面是由于北方气候与生态条件的限制，另一方面是育种技术相对落后。解决优势与生育期的矛盾、产量与品质的矛盾以及提高制种产量等问题，仍然是北方超级杂交粳稻育种所面临的严峻挑战。本文还讨论了与粳型超级稻育种有关的生理和遗传问题。     

中国超级稻育种研究进展与前景

综合评述了中国超级稻育种研究进展与前景,认为培育和推广超级稻,是继株型改良和杂交稻育种之后,提高水稻综合生产能力,实现水稻单产水平进一步提高的重要途径。在"利用籼粳稻杂交创造新株型和强优势,通过复交优化性状组配聚合有利基因,选育理想株型与优势利用相结合的超级稻"育种理论与技术路线确立之后,在常规超级稻育种和超级杂交稻育种两方面都已取得重大突破,成功地创造出一批新株型优异种质,培育出一批优质抗病的超级稻新品种和新组合。这些超级稻新品种、新组合已广泛地应用于水稻生产实践,并已取得较好的增产效果。     

中国北方粳型超级稻研究进展

1996年农业部正式启动中国水稻超高产育种即超级稻研究项目,20年来中国超级稻研究后来居上,无论超高产遗传生理基础研究还是超级稻育种实践,无论南方超级杂交籼稻还是北方超级常规粳稻,总体上都处于国际领先水平,为探索进一步提高生产潜力和将其转化为现实生产力提供了科学依据和技术储备,为中国稻作科学保持国际先进水平作出了突出贡献。文章从超级稻兴起、技术路线确立、新品种选育与示范推广、生理与遗传基础研究等方面综合评述了中国北方粳型超级稻研究进展。在此基础上讨论了北方粳型超级稻相关生理与遗传问题：近年来北方粳稻继续保持较高产量水平和加工品质,同时以垩白性状为代表的外观品质有明显提高,至少在9 t·hm^-2之前产量与主要品质性状的矛盾并不突出,产量和品质可以在更高水平上达成新的平衡;分析北方粳稻区域试验结果表明,通过延长生育期提高产量是不足取的,通过增加株高提高产量也是行不通的,提高稻瘟病抗性是北方粳稻的重要育种目标;北方粳稻着粒密度普遍较高,但是对产量构成因素和主要品质性状的负面影响相对较小,可以认为经过育种家的不懈努力,北方粳稻着粒密度处于比较合适范围;籽粒长宽比是决定籼粳稻碾磨品质的主要因素,而对外观品质亚种间差异影响较小,近年来中国籼稻碾磨品质有明显改善,籼粳稻差异幅度有所降低,籼粳稻外观品质均有明显改善,但是籼粳稻差异依旧。建议：在全面总结20年来中国超级稻研究成果与经验基础上,明确今后超级稻研究的方向与目标,改设立阶段性产量目标分期攻关为按生态区长期稳定支持,改小面积产量验收评价指标为考核大面积均衡增产。根据北方粳稻生态、生产和品种特性,有针对性地开展育种基础理论和关键技术研究,如籼粳血缘与产量和品质关系的遗传和生理生态机制,从分子、细胞、组织、器官、个体、群体水平全面评价直立穗型基因EP1功能,有效改良籼粳稻杂交育成直立大穗型品种品质特别是食味品质,充分利用分子生物学相关理论、技术研究成果,在抗稻瘟病、抗冷性和耐盐碱种质创新及育种应用上有所突破。     

我国超级杂交稻育种研究进展及展望

回顾了国内外超级稻育种历史,介绍了我国超级稻育种研究进展,指出我国超级稻育种在籼粳亚种优势利用及株型育种中取得了重大突破,超级稻在我国已处于大面积推广阶段。针对我国超级稻品种（组合）普遍存在适应性不广、结实率偏低、抗性及米质较差、双季超级稻品种（组合）较少及育种理论和技术还有待完善等问题,提出未来超级稻育种的策略。     

Yield potential and stability in super hybrid rice and its production strategies

China's Super Hybrid Rice Breeding Program has made significant progress over the past two decades. In this paper, we reviewed our studies on the yield potential and stability in super hybrid rice and discussed the strategies for super hybrid rice production. The results of our studies show that rice yield potential has been increased by 12% in super hybrid cultivars as compared with ordinary hybrid and inbred cultivars. The higher grain yields in super hybrid rice cultivars are attributed to larger panicle size coupled with higher biomass production or higher harvest index. However, grain yields in super hybrid rice cultivars vary widely among locations depending on soil and climatic factors. Therefore, it is important to tailor target yield to local conditions in super hybrid rice production. The target yield for super hybrid rice production can be determined by the average yield method or the regression model method. Improving soil quality is critical to achieving the target yield in super hybrid rice production. Favorable crop rotations such as rice-oilseed rape and novel soil management practices, such as biochar addition, are effective approaches to improve soil quality. It is needed to develop simplified cultivation technologies for super hybrid rice to meet the changes in socioeconomic environments during the period of transition. There are such technologies as no-tillage direct seeding and mechanized transplanting at high hill density with single seedling per hill.     

超级稻育种技术和途径的探讨

回顾了超级稻发展的历程,由于育种技术和栽培方法不断开拓创新,中国水稻最高单产屡屡突破世界纪录,超级稻育种技术居世界领先水平。在综观国内外超级稻育种研究现状的基础上,综述了水稻产量的理论极限及超级稻育种技术,并提出了对今后超级稻育种的看法。     

Breeding strategies for increasing yield potential in super hybrid rice

Super hybrid rice breeding is a new breeding method combining semi-dwarf breeding and heterosis breeding using germplasm and gene-environment interactions. This paper reviews the breeding strategies of super hybrid rice breeding in China, focusing on the utilization of heterosis of indica and japonica subspecies, construction of ideal plant architecture and pyramiding of disease resistant genes in restorer lines. To develop super hybrid rice, considerable effort should be made to explore genes related with high yield, good quality, resistance to pests and diseases, tolerance to stresses. Molecular breeding methods in combination with crossing techniques should be adopted in super hybrid rice breeding.     

华南生态区超级稻育种的主要成就及未来发展趋势

中国超级稻研究项目启动至今,对促进我国的粮食增产,提升我国水稻育种水平发挥了重要作用。广东省农业科学院自1996年以来,作为中国超级稻研究项目主要发起和承担单位,承担了该项目的华南稻区超级稻选育研究工作。在开创水稻生态育种并取得显著成就的基础上,经过10年攻关,再创华南超级稻育种新辉煌。先后构建出"早长、根深"超级稻株型模式和华南广适应型优质超级稻株型模式;在优质超级晚稻育种和广适型超级稻育种方面率先取得重大突破;先后育成一批达标优质超级稻,主要代表品种有:品质可与泰国优质香米相媲美的优质超级稻品种胜泰1号、我国超级晚稻育种取得突破的先锋品种桂农占和大穗高结实的广适型超级稻品种玉香油占等,这些超级稻正迅速在生产上大面积推广应用,创造了显著的社会经济效益。     

南方稻区超级杂交中稻育种研究进展

南方稻区的杂交中稻生产是中国水稻生产的重要组成部分,由于育种技术路线正确,中国率先在超级杂交中稻育种上取得了突破性进展。对中国在超级杂交中稻亲本选育、新组合配制、育种技术体系的建立和推广应用上所取得的进展进行了回顾,指出了在广适性组合较少、推广力度不够,影响超级杂交稻的快速发展,以及高产、优质和高抗有机结合的组合少等方面存在的问题,要从拓宽水稻遗传基础,选育广适性组合、发掘特异种质资源,选育综合性状优良的超高产组合、建立轻型化配套栽培技术体系,加强推广力度3个方面去解决存在的问题,并讨论了中国在超级杂交中稻育种中应加快已有研究成果的转化,选育具有广适性、综合性状优良的超级杂交中稻组合,加强第三期超级杂交稻的研究等方面的研究重点。     

野生稻种质在水稻高产育种上的应用研究进展

野生稻种质拥有许多优良的性状和基因,与栽培稻的亲缘关系最近,是栽培稻遗传改良的重要候选资源.文章通过综述野生稻种质在常规稻、三系杂交稻、两系杂交稻上的应用研究进展,并结合生产实践对水稻高产育种方向提出了建议:在科研体制上应加强顶层设计,允许实施一定数量的中长期育种项目,为培育重大品种创造环境;对于普通野生稻的利用,宜选择具有所需优异性状的栽培稻作亲本进行回交、复交或选择不同野栽杂交后代中的优良株系进行兄妹交,使各亲本的优良基因结合于同一栽培品种上;通过胚拯救、转基因、花粉管导入或穗茎注射野生稻DNA、MAS等方法相结合、构建野生稻外源种质渗入的近等基因系和染色体片段替换系等生物技术手段,充分利用其优异性状;利用骨干亲本材料与野生稻种质资源构建遗传材料进行基础理论研究,同时利用MAS技术在骨干亲本材料中进行高产QTL遗传效应验证,从而促进遗传育种科研项目在实践中推广应用.     

超级稻生态育种及超高产栽培特征与途径的研究进展

超级稻是目前作物生产领域的研究热点。围绕超级稻,回顾了超级稻育种的发展,并重点介绍了几种典型生态稻区株型模式,进而分析了超级稻的一些栽培特征,最后展望了超级稻的未来和发展方向。超级稻穗大粒多、叶片直挺、株型紧凑、茎秆粗壮、根系健壮,抽穗后干物质生产积累优势明显,超级稻栽培根本途径在于“强支撑、扩库容、促充实”。     

对黑龙江垦区超级稻研究的思考

超级稻育种是中国自主创新的重大技术,综述了超级稻的定义、名称来源及其研究过程;中国超级稻的研究现状,并就黑龙江垦区超级稻研究提出了几点思考,即培育超级稻新品种、发掘现有品种增产潜力、深入研究寒地水稻增产潜力机理和良种良法配套等。     

Analysis on potential approaches to utilize genic male sterility in plant hybrid breeding

The exploitation of plant heterosis is an effective approach to increasing the food production. The heterotic hybrid varieties in major crops such as rice, cotton, and wheat can show more than 20% yield advantage over best conventional ones under the same cultivation conditions. The difficulties in breeding elite male sterile lines and the inconveniences for commercial hybrid seed production are hampering the development of hybrid crops breeding.     

两系法杂交稻两优培九育种的理论与实践

两系法超级杂交稻两优培九是中国独创的两系法杂交稻育种中形成的品种,是中国超级稻育种计划完成第一步目标的标志性品种,是继三系杂交稻汕优63之后种植面积最大的杂交稻,在国内外具有重大影响。两优培九的育种实践经历了艰苦曲折的科研攻关和推广过程。最初是尝试通过化学杀雄制种的方法利用典型籼粳杂种的优势,在亚优2号的育种实践失败后,技术路线调整为通过光温敏两系法将部分亚种间杂种优势与江淮生态区的水稻理想株型相结合,克服杂交稻结实率不高、不稳等弱点,达到高产、优质、多抗、适应性广泛并能安全制种的目标。通过分析多个水稻光温敏不育系与不同生态型父本配组的杂种F1的性状表现,确定以带有1/4爪哇稻亲缘的培矮64S为重点母本,选择优势生态群中的合适类型父本重点配组,避开生育期超长和植株偏高等障碍性问题,并根据江淮流域一季稻区的常年气候特点进行生态育种。通过大量筛选,育成两优培九,达到遗传、形态和功能“三优”的统一,将优质、超高产、多抗性状聚集于一体。通过对培矮64S育性转换、开花授粉有危害的高温、低温指标的研究和对各生态区常年气候中出现这些温度频率的分析,提出适宜制种区域和相应的父母本安全抽穗期。研究培矮64S育性转换的植株温度指标,提出遭遇低温危害时“以水调温”的制种纯度保障技术。通过对两优培九的生物学特性和适宜生长条件的研究,提出适宜种植区、各种植区的适宜齐穗期和主要种植方式的播栽期等生产指导性指标,分析生产上可能发生的问题并提出相应的预防措施和解决对策,研发提高结实率及其稳定性的栽培技术。通过配套生产技术的系统研究和应用,两优培九在南方稻区多年大面积成功种植。通过全程回顾育种战略的形成、研究思路和技术路线、品种培育和核心配套技术的研发及示范推广过程,论述了两优培九育成和大面积应用的意义;补充了水稻理想株型中的茎秆分布性状,提出“渔叉型”茎秆分布的概念;认为可以利用籼粳米质性状的互补选择各种适口性的稻米;大面积成功推广一个品种,尤其要加强应用技术研究,前瞻性地研究品种的最适生长条件,然后根据各地的气候条件规划最适种植区,并制定相应的最优栽培措施,还要储备可能发生问题的预防措施和解决对策。     

不同类型水稻品种的产量构成因素与产量的关系

本试验研究了不同类型品种在10.5～11.25 t.hm-2的目标产量下产量构成因素与产量的关系,为高产栽培提供理论依据。以在四川应用较多的超级稻品种和非超级稻品种为材料,研究不同类型品种连续3年高产栽培条件下的产量表现,进而分析其产量构成因素与产量的关系。研究表明:超级稻的产量与穗数、千粒重关系密切,同时,与穗粒数成显著负相关,与结实率成负相关,但未达显著水平。非超级稻品种的产量与穗数、穗粒数、结实率、千粒重呈负相关,且与穗粒数、结实率呈显著负相关。明确不同类型品种的产量构成因素与产量的关系,可以制订合理的高产栽培技术措施,充分发挥超级稻的产量潜力,实现水稻大面积稳产高产具有重要意义。     

广西优质常规稻育种现状及发展对策

根据2000~2011年广西育成并通过审定的50个优质常规稻品种的米质、产量、抗性等,分析了广西优质常规稻品种育种现状及存在问题,如米质虽已取得较大改良但直链淀粉含量仍偏低;育成了一系列米质优且产量高的香稻品种如广香1号、三香628、桂香3号、柳丰香占、家福香1号、兆香1号等;近3年(2009~2011年)的优质常规稻产量明显稳定提升,每年均超过6600 kg/ha,但育成水稻品种抗病性普遍较差,抗病育种徘徊不前等.今后需根据稻米市场导向,以长粒型、高胶稠度、中等偏低直链淀粉含量、低垩白度的大米类型为选育目标;引进国内外现有的中等直链淀粉含量的优质品种资源,直接或创新后作为杂交亲本加以利用;以粗长粒型作为选育目标,通过提高千粒重来进一步提高优质常规稻的单产;加大资金投入,提高育种技术,并加大抗病及抗逆育种力度,提高现代生物技术在优质常规稻育种中的应用等.     

云南德宏杂交籼稻品种农艺性状与产量的相关性

为探讨云南省德宏州籼稻品种农艺性状与产量的关系,采用单相关、偏相关、回归分析和通径分析等多种分析方法对2020年德宏州品比试验中的42个水稻品种进行综合评价。结果表明,有效穗数、穗实粒数、千粒质量均与产量呈显著正相关。主成分分析提取了穗数因子、粒数因子、粒重因子和穗长因子4个主成分,累计贡献率达85.29%。根据各品种主成分得分进行综合排序,锦两优906、泸优164、花优33分列前3位。聚类分析将42个品种聚为5个类群,第Ⅵ类可作为生产上高产栽培的优势品种,第Ⅴ类可作为早熟高产育种的优异资源。依据各类型品种的特征,笔者提出了针对性的高产育种目标和栽培建议。