Progress in ideotype breeding to increase rice yield potential

The ideotype approach has been used in breeding programs at the International Rice Research Institute (IRRI) and in China to improve rice yield potential. First-generation new plant type (NPT) lines developed from tropical japonica at IRRI did not yield well because of limited biomass production and poor grain filling. Progress has been made in second-generation NPT lines developed by crossing elite indica with improved tropical japonica. Several second-generation NPT lines outyielded the first-generation NPT lines and indica check varieties. China's “super” rice breeding project has developed many F₁ hybrid varieties using a combination of the ideotype approach and intersubspecific heterosis. These hybrid varieties produced grain yield of 12 t ha⁻¹ in on-farm demonstration fields, 8–15% higher than the hybrid check varieties. The success of China's “super” hybrid rice was partially the result of assembling the good components of IRRI's NPT design in addition to the use of intersubspecific heterosis. For example, both designs focused on large panicle size, reduced tillering capacity, and improved lodging resistance. More importantly, improvement in plant type design was achieved in China's “super” hybrid rice by emphasizing the top three leaves and panicle position within a canopy in order to meet the demand of heavy panicles for a large source supply. The success of “super” hybrid rice breeding in China and progress in NPT breeding at IRRI suggest that the ideotype approach is effective for breaking the yield ceiling of an irrigated rice crop.     

2013年我国通过审定的水稻品种产量及品质性状分析

2013年,我国通过省级以上审定的水稻品种共有422个,其中,籼型常规稻20个、籼型三系杂交稻180个、籼型两系杂交稻84个、粳型常规稻113个、粳型三系杂交稻15个、粳型两系杂交稻3个、不育系7个;每667 m2产量籼型常规稻为463.35 kg、籼型三系杂交稻为539.70 kg、籼型两系杂交稻为557.03 kg、粳型常规稻为584.80 kg、粳型杂交稻为629.95 kg;品质优质达标率粳稻为58.78%,明显好于籼稻的39.08%,常规稻为59.40%,明显好于杂交稻的38.30%。达优质1级的品种有7个,分别是宏科79、吉农大878、金穗9号、泰优390、五优华占、黄华占和粤齐新占;综合抗性表现优异的品种不多,但有些品种对单个病害的抗性表现较突出。对2013年审定的水稻品种与2010-2012年审定的品种作了比较。     

我国杂交籼稻选育进展

自水稻杂种优势被利用以来,我国杂交籼稻育种取得显著进展,在保障我国粮食安全中发挥着重要作用。本文根据国家水稻数据中心水稻品种审定数据信息,对我国籼型水稻不育系研究进展、杂交籼稻品种审定情况、籼型超级稻品种发展现状和几个籼稻育种大省的杂交籼稻国审情况进行了对比和分析,并对杂交籼稻的发展进行了展望。     

Yield potential and radiation use efficiency of “super” hybrid rice grown under subtropical conditions

China's “super” hybrid rice breeding project has developed many new varieties using a combination of the ideotype approach and intersubspecific heterosis. It is controversial whether these “super” hybrid varieties have increased the yield potential of irrigated rice. This study was conducted to compare grain yield and yield attributes among “super” hybrid, ordinary hybrid, and inbred varieties. Field experiments were done in Liuyang (moderate-yielding site) and Guidong (high-yielding site) counties, Hunan Province, China, in 2007 and 2008. Two varieties from each varietal group were grown in each field experiment under moderate and high N rates. Grain yield, yield components, aboveground total dry weight, harvest index, total N uptake, and crop radiation use efficiency (RUE) were measured for each variety. A significant difference in grain yield was observed among the varieties and varietal groups but not between the two N rates. “Super” hybrid varieties have increased rice yield potential by 12% compared with ordinary hybrid and inbred varieties. The higher grain yield of “super” hybrid varieties was attributed to improvement in both source and sink. “Super” hybrid varieties produced more biomass than ordinary hybrid and inbred varieties. Long growth duration and high accumulated incident radiation were partially responsible for high biomass production for the “super” hybrid varieties. “Super” hybrid varieties had significantly larger panicle size (spikelets per panicle) than ordinary hybrid and inbred varieties, which resulted in larger sink size (spikelets per m²). Crop RUE did not explain the yield superiority of “super” hybrid rice. Our study suggests that “super” hybrid rice varieties do not necessarily require more N fertilizer to produce high grain yield.     

Review and Prospects on Rice Breeding and Extension in China

Rice is the most important food crop in China. In 2004, the planting area was about 2.8973×107 ha accounting for 28.5% of the total planting area of food crops, and the yield reached 1.7769×107 t accounting for 37.8% of the total food output. Breeding a…     

中国水稻品种对白背飞虱的抗性

评价了来自中国的13个粳稻品种、11个籼稻品种、13个杂交稻组合,以及11个热带粳稻品种的杀卵作用和拒食抗性.具有杀卵作用的品种仅见于粳稻品种.测试的13个粳稻品种中,4个表现出明显的杀卵作用.重新评价了来自中国不同省份的42份粳稻和43份籼稻对白背飞虱的抗性.10个粳稻(约占24%)具有杀卵抗性,卵死亡率为53%～100%;95%以上的籼稻品种中,白背飞虱的卵死亡率低于30%;来自浙江的4个粳稻品种明显地抑制白背飞虱的取食.浙江的21个粳稻地方品种对白背飞虱拒取食和杀卵作用表现出独立性和连续变化.三千黄、长红稻和矮秆稻具有杀卵抗性,鸡脚黄和麻雀青具有拒取食抗性.这些发现表明抗白背飞虱基因在中国存在于同一生态区的粳稻地方品种中.     

2001-2018年通过河南省审定的水稻品种情况分析

对2001-2018年通过河南省审定的水稻品种基本情况及其产量、米质等性状进行了介绍分析。结果表明,2001-2018年河南省通过审定品种132个,其中籼型水稻77个、占比58.33%,粳型水稻54个、占比40.91%,籼粳杂交稻1个、占比0.76%;育种单位涉及科研、教学及推广单位、种业企业等,种业企业选育或参与选育的品种比例正逐渐增加;审定品种年度间产量总体呈上升趋势,并以粳型杂交稻和籼型两系杂交稻产量最高;46.21%的水稻品种达到国标优质稻谷等级,粳型水稻优质达标率高于籼型水稻,垩白粒率和垩白度是限制河南稻米品质等级的主要因素,有待进一步提高。     

Genetics and Improvement of Bacterial Blight Resistance of Hybrid Rice in China

Since 1980s,rice breeding for resistance to bacterial blight has been rapidly progressing in China. The gene Xa4 was mainly used in three-line indica hybrid and two-line hybrid rice. The disease has been ‘quiet’ for 20 years in China,yet in recent years it has gradually emerged and been prevalent in fields planted with newly released rice varieties in the Changjiang River valley. Under the circumstances,scientists inevitably raised several questions:what causes the resurgence and what should we do next? And...     

2016年我国审定的水稻品种及基本特性分析

分析了2016年我国水稻品种的审定情况及通过省级以上审定水稻品种的基本特性.结果表明,2016年我国通过省级以上审定的水稻品种共有492个次(有13个品种通过两个及以上省份审定),其中,籼型常规稻36个、籼型两系杂交稻137个、籼型三系杂交稻166个、粳型常规稻87个、粳型杂交稻25个(其中19个为籼粳杂交稻)、 不育系41个.区试平均产量籼型常规稻为501.36 kg/667 m2,比区试对照增产3.86%;籼型两系杂交稻为592.54 kg/667 m2,比区试对照增产5.46%;籼型三系杂交稻为552.96 kg/667 m2,比区试对照增产5.16%;粳型常规稻为624.94 kg/667 m2,比区试对照增产7.48%;粳型杂交稻为651.96 kg/667 m2,比区试对照增产8.91%.品种品质表现是粳稻好于籼稻,常规稻好于杂交稻,优质达标率粳稻为51.79%、籼稻为43.95%,常规稻为56.91%、杂交水稻为41.77%.并列举了一些对单个病害抗性表现较好的品种.     

Practice and Thought on Developing Hybrid Rice for Super High Yield by Exploiting Inter-subspecific Heterosis

Since the breakthrough of grain yield owing to the development of dwarf rice and three-line system hybrid rice, rice breeding for high yield hardly had showed significant progress in the next successive two decades. It was considered that utilizing heterosis between subspecific varieties (Oryza sativa L.) would be an effective approach to increase yield further. During 1987-1993,an indica-japonica hybrid Yayou 2 yielded as high as 10.5 t/ha; however, it failed to be commercialized because of seed purity problem due to non-uniform emasculation by chemical agent in seed production, and sensitivity of seed setting in F1 plants to environmental conditions. In the past decade, two inter-subspeific hybrids, Liangyoupeijiu (Peiai 64S/9311, javanica/indica) and Liangyou E32 (Peiai 64S/E32, javanica/japonica); both of them exhibited grain yield higher than 10.5 t/ha, and were widely judged as the pioneers of super hybrid rice. Liangyoupeijiu has been successfully popularized over 4 million hectare in wide climatic areas, while Liangyou E32 made a yield record and offered a model of plant ideotype for super hybrid rice. It was considered that in combination with plant ideotype, active physiological functions, and wide-range adaptability to ecological conditions, exploitation of indica-japonica heterosis would be the key approach for super hybrid rice breeding.     

中国杂交水稻白叶枯病抗性的遗传改良

 20世纪80年代,中国杂交水稻抗白叶枯病育种进展迅速。在大面积种植的籼型三系和两系杂交稻中主要应用白叶枯病抗性基因Xa4,白叶枯病在生产中几乎“销声匿迹”了20年。但近年来,此病害却在长江流域一些种植新组合的稻田里又爆发了。什么原因引起它再度流行？品种的抗性是否还有效？抗病育种是否还是水稻改良的主要目标之一？通过哪些途径才能更有效地利用抗病基因培育出更为持久的抗性品种？为回答这些问题,就我国杂交水稻对白叶枯病抗性的改良,寄主与病菌群体的互动演变效应进行了分析,讨论了拓宽抗性遗传基础、白叶枯病菌毒性群体结构、基因轮换、合理利用基因等问题。 在采用了包括传统方法、分子标记辅助选择和转基因技术的综合策略后,杂交水稻抗白叶枯病育种研究将出现新的局面。     

极端高温天气对杂交中籼稻生育特性的影响

在极端高温天气下，对大面积杂交中籼稻生长情况进行跟踪调查。调查结果表明，当前水稻生产中杂交中籼品种抗高温能力较强；不同杂交中籼品种抗高温能力有差异；在一定范围内，播期越早，极端高温天气对杂交中籼稻产量影响越大。     

Comparison of Different Methods of Rice Establishment and Nitrogen Management Strategies for Lowland Rice

Abstract

Shortage of labor and water are forcing farmers to explore the alternatives of transplanting. A field experiment was conducted at the experimental farm of International Rice Research Institute (IRRI), Philippines during the 2003 wet season and the 2004 dry season to (1) evaluate the effects of different crop-establishment methods and N management on yield and yield parameters of rice; (2) determine N-use efficiency and water-use efficiency under different methods of rice establishment; and (3) analyze the economics of different crop-establishment methods. Crop-establishment method did not influence grain yield during the wet or dry seasons, indicating the potential of the three variants of direct seeding as alternative methods of establishing lowland rice. Direct-seeded rice had shorter crop duration, required less water and therefore had higher water-use efficiency than the transplanting method. Crop establishment did not influence the various indices of nitrogen-utilization efficiency except partial factor productivity of N (PFPN) during the wet season. During the dry season, dry-seeded rice had the lowest recovery efficiency. In contrast, agronomic-use efficiency and recovery efficiency were significantly higher in the SPAD-based (soil plant analyses development) N management strategy during the dry season. PFPN was significantly higher in the SPAD-based N management strategy during the wet and dry seasons. The interaction effect of crop establishment and N management indicated that for smaller N input and higher efficiency of N usage, N requirement for direct-seeded rice should be based on SPAD N technique. The cost-and-return analysis showed that benefit-cost ratio was consistently higher in dry seeding rice than transplanted rice using a SPAD-based N management.     

粳型亲籼系的选育及其在杂交水稻超高产育种上的利用

杂交水稻超高产育种的关键是籼粳亚种间杂种优势的利用。粳型亲籼系的选育和利用是籼粳亚种间杂种优势利用的重要途径,作为超高产杂交水稻的强优恢复系,粳型亲灿系的育种目标是：１）对籼稻具有很高的亲和性;２）基因组属于粳型或偏粳型;３）与籼稻具有遗传协调性;４）具有良好的农艺性状;５）带有一些重要基因,对通过利用粳型亲灿系建立超高产要交水稻的育种体系进行了讨论。     

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。     

Increasing Production of Rainfed Lowland Rice in Drought Prone Environments

Summary

Drought is a major production constraint of rainfed lowland rice grown in Thailand and Laos. Adverse soil conditions also reduce yield. In an attempt to increase rainfed lowland rice production in these countries, a major collaborative international project was conducted during a 6-year period in the region. The objectives of the project were to quantify production constraints, determine genotypic variation in yield, and identify an effective breeding strategy. A rice simulation model was developed also and used to investigate the potential impact of strategies for genetic improvement and agronomic management.

Four major physical or biological constraints to higher production levels of rainfed lowland rice were identified, (1) the lack of standing water at the appropriate time of transplanting, (2) severe water stress that often develops at the end of the growing season, (3) low yield potential of the present cultivars, particularly in Thailand, and (4) adverse soil conditions including low pH and low soil fertility. The results of the field experiments and simulation modelling exercises showed that the influence of these constraints can be reduced and yield increased by several methods : in particular, choice of appropriate cultivars and time of sowing to match crop phenology with water availability, application of appropriate fertilizer, adoption of high yielding cultivars, adoption of direct seeding in place of the traditional transplanting system, and reduction of percolation water loss from the paddies.

A technology package currendy being investigated for the rainfed lowland rice is direct seeding early in the season, using cultivars that flower by the end of the rainy season, with application of organic or chemical fertilizer. The appropriate cultivars are early flowering and short-intermediate statured, possess high yield potential and ability to maintain favourable plant water status at flowering, and have the ability to establish well and compete against weed under direct seeding.     

北方超级粳稻育种研究进展与前景

从育种理论、育种技术及新品种选育等方面,综合评述了中国北方超级粳稻育种研究的进展与前景,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,通过回交或复交优化性状组配,聚合有利基因,进而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,常规超级梗稻育种已取得了重大突破,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。与常规超级稻育种相比,超级杂交粳稻育种研究进展相对较缓慢。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研究相对落后。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。讨论了与超级粳稻育种有关的生理和遗传问题。     

栽培稻抗旱性研究的现状与策略

 水资源短缺正成为制约我国农业发展的重要因素。培育抗旱的栽培稻品种并实现水稻旱作，不但可在很大程度上节约水资源，而且有利于增产稳产，节约能源和减少环境污染。抗旱性包括逃旱性、避旱性、耐旱性和复原抗旱性。形态生理学的研究揭示出大量的与栽培稻抗旱性有关的形态特征和生理特性，如根系和叶片性状、生育期、渗透调节、脱落酸含量与栽培稻抗旱性密切相关，且已利用分子标记对上述性状进行了基因定位（QTL）研究。旱稻品种改良也已取得重大进展。在进行抗旱品种改良的基础上，通过引进相应的栽培技术，节水种植，实现水稻旱作，并达到稳产与增产的目的，是抗旱性研究的战略目标。在增产、稳产和优质的前提下，以培育耐旱性极强的水稻（或旱稻）为中心，建立有代表性的抗旱性研究基地, 进一步加强稻属抗旱基因资源的发掘和创新、抗旱生理学和遗传学的研究、利用现代生物技术实现不同物种间抗旱基因的转移、建立节水种植栽培技术新体系是目前抗旱性研究的主要内容。     

用遗传距离划分籼型水稻优势生态型

利用6个籼型水稻生态型的72份亲本为材料,对主要农艺性状进行主成分分析,以欧氏距离为指标,研究了各生态型间遗传差异。结果表明,云贵籼和华南籼之间的遗传距离最大,为6.345 1,韩国籼与IRRI籼之间的遗传距离最小,只有2.914 1。由于云贵籼和华南籼与其它生态型之间的遗传距离均较大,故初步将其确定为籼型水稻优势生态型。     

后期功能型超级杂交稻的概念及生物学意义

 在借鉴国际水稻研究所新株型育种经验基础上，我国于1996年开始实施中国超级稻育种计划，采取的技术路线是理想株型塑造与籼粳亚种间杂种优势利用相结合，至2005年的目标产量是在百亩（6.67 hm2）规模下单季稻达到12 t/hm2（800 kg/667 m2）。介绍了国外水稻超高产育种和国内超级稻育种的基本情况，着重介绍了由中国水稻研究所育成的超级杂交稻组合“协优9308”。该组合表现出高产与优良株型的完美结合，生育后期青秆黄熟，结实率高，籽粒饱满。2000年在浙江新昌验收百亩片平均产量达到11 837 kg/hm2，最高产田块产量达到12 282 kg/hm2。以“协优9308”为例，提出了“后期功能型”超级杂交稻的概念和生理特征，并对今后的超级杂交稻育种策略进行了讨论。