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。     

水稻抗旱性的主要鉴定指标及其抗旱相关基因的分子生物学研究进展

水资源短缺日益成为限制农业发展的严重问题,水稻作为用水量最多的农作物,其抗旱性研究尤其重要。本文主要介绍与水稻抗旱性有关的一些农艺性状和生理生化指标,及水稻抗旱相关基因的定位克隆及转基因研究进展。     

旱稻病虫草鼠发生与防治技术初报

一、概况干旱缺水是我国水稻生产面临的最大威胁 ,也是制约我国稻作面积扩大和产量提高的重要因素。旱稻是一种抗旱性极强的栽培稻类型 ,可在节约７０%用水的情况下取得与栽培稻相似的产量 ,应用旱稻实现水稻旱作对于节约水资源、增加粮食产量、减少能源消耗、保护生态环境具有重要意义。试验表明 :旱稻适合在干旱条件及无灌溉设施的靠天田、坡耕地上种植 ,由于旱稻的根系长且发达 ,保土效果良好 ,旱稻种植地块的土壤侵蚀与全园植草地块土壤侵蚀量相近 ,其单位面积流失量仅为６７．７７ｔ／ｋｍ２ ,比无植被覆盖的幼林果园地减少７５．８%。…     

栽培稻抗旱性的田间评价方法

干旱是造成水稻减产的主要原因之一。评价和选育抗旱的栽培稻品种不仅有利于增产稳产 ,而且可以节约水资源 ,减少环境污染。作物的抗旱性 ,指作物在大气或土壤干旱条件下生存或形成产量的能力。Ｔｕｒｎｅｒ将作物在缺水的条件下获得产量的能力称之为抗旱性。Ｌｅｖｉｔｔ等将抗旱性定义为供水量很低的情况下 ,植物可以生存的能力。抗旱性可分为避旱性、逃旱性、耐抗旱性和复原抗旱性。洛克菲勒基金总干事Ｂｌｕｍ提出 ,缺乏适当的对作物抗旱性的标准评价体系已成为抗旱性改良的尖锐问题。抗旱性是一个复杂的现象 ,是植物内在水分与生理功能…     

水稻无水层栽培初探

针对辽宁稻区缺水和水资源浪费现象,进行了本项研究,结果表明无水层栽培可以降低水稻的无效分蘖、穗粒数,提高有效穗数、千粒重。无水层栽培全生育期可节水35%以上,有利于缓解北方稻区用水紧张问题,是一项值得推广的水稻节水新技术。     

旱稻品种筛选及其水土保持效果的初步研究

干旱缺水是我国水稻生产面临的最大威胁 ,也是制约我国稻作面积扩大和产量提高的首要因素。旱稻是一种抗旱性极强的栽培稻类型 ,可在节约７０%用水的情况下取得与栽培水稻相似的产量 ,应用旱稻对于节约水资源、增加粮食产量、减少能源消耗、保护生态环境具有重要的意义。浙江省安吉县地处浙江北部 ,山地丘陵面积占全县总面积的７５ % ,有４０００ｈｍ２ 没有灌溉条件的望天田 ,而且安吉频繁出现季节性干旱 (主要出现在６～９月 ,正是作物生长季节 )。因此 ,旱稻在安吉县具有较高的推广应用价值。本研究旨在利用安吉县的自然生态条件 ,鉴定评…     

节水抗旱稻的研究进展

水资源短缺给水稻生产带来严重的威胁,节水抗旱性的研究是当今水稻研究的热点之一。对水稻节水抗旱的鉴定指标、相关基因的定位和克隆以及节水抗旱水稻品种的选育进行了概述。     

干湿交替灌溉对抗旱性不同水稻品种产量的影响及其生理原因分析

【目的】旨在阐明全生育期干湿交替灌溉对抗旱性不同水稻品种产量的影响。【方法】以抗旱性差异显著的4个水稻品种(籼稻扬稻6号和两优培九,粳稻旱优8号和镇稻88)为材料,以常规水层灌溉(CI)为对照,在盆栽条件下研究了轻干湿交替灌溉(WMD)和重干湿交替灌溉(WSD)对水稻产量、根系、叶片及籽粒部分生理特性的影响。【结果】与CI相比,WMD处理下抗旱性较强品种扬稻6号和旱优8号产量分别提高6.90%和7.45%,抗旱性较弱品种两优培九和镇稻88产量分别降低7.28%和8.10%。WSD处理下,4个水稻品种的产量均显著下降,抗旱性较弱的品种产量降幅远高于抗旱性较强的水稻品种。WMD处理下,扬稻6号和旱优8号复水后根系氧化力、根系与叶片细胞分裂素(玉米素+玉米素核苷)含量、叶片光合速率和籽粒中蔗糖-淀粉代谢途径关键酶的活性均较CI有不同程度提高,而两优培九和镇稻88上述指标则与CI持平或有不同程度降低。WSD处理下,4个品种上述指标均较CI不同程度降低。【结论】轻干湿交替灌溉条件下,根系活性强、叶片细胞分裂素含量和光合速率高、籽粒中蔗糖-淀粉代谢途径关键酶活性强是抗旱性较强水稻品种的基本生理特征。     

水稻无水层栽培初探

针对辽宁稻区缺水和水资源浪费现象，进行了本项研究，结果表明无水层栽培可以降低水稻的无效分蘖、穗粒数，提高有效穗数、千粒重。无水层栽培全生育期可节水35％以上，有利于缓解北方稻区用水紧张问题，是一项值得推广的水稻节水新技术。     

"热大99W"序列旱稻新品系农艺特征与抗旱特性的研究

海南山栏稻原种与水稻常规品种杂交,Ｆ２或Ｆ３单株再与水稻雄性不育恢复系杂交,其后代又与雄性不育系再杂交,在四交Ｆ６代进行单株选择,Ｆ７代进行株系选择,Ｆ８代对入选的９个品系进行农艺性状比较、产量构成分析和抗旱生理指标测验。结果表明其中３个品系具有良好的农蕊性状和较高的产量潜力（产量可超过４５００ｋｇ／ｈｍ＾２）,同时表现较强的抗旱性。从而获得兼备水稻理想株型和山栏稻抗旱性的丰产旱稻新品系,为进一步培育优良旱稻新品种奠定了重要基础,并对稻作抗旱育种的技术路线进行了有益的探讨。     

北方旱作水稻研究现状及发展前景

阐述了我国北方旱稻研究现状,分析了旱作条件下水稻生物学性状、生理生化变化规律及旱作水稻产量及其构成因素与其它性状、品质与其它性状的相关关系,指出产量的提高与品质的改良并不存在矛盾,育种工作者完全可以培育出集高产、优质于一身的旱稻品种。评价了旱作水稻各抗旱性鉴定指标,指出综合抗旱力指数K值法作为一种鉴定水稻品种的综合抗旱能力研究方法较为客观、准确,且易于掌握利用。并从旱作水稻研究现状、生产实际出发,结合我国北方气候特点、水资源情况,分析了我国北方发展旱稻的可行性及其广阔的发展前景。     

北方旱作水稻研究现状及发展前景

阐述了我国北方旱稻研究现状,分析了旱作条件下水稻生物学性状、生理生化变化规律及旱作水稻产量及其构成因素与其它性状、品质与其它性状的相关关系,指出产量的提高与品质的改良并不存在矛盾,育种工作者完全可以培育出集高产、优质于一身的旱稻品种。评价了旱作水稻各抗旱性鉴定指标,指出综合抗旱力指数K值法作为一种鉴定水稻品种的综合抗旱能力研究方法较为客观、准确,且易于掌握利用。并从旱作水稻研究现状、生产实际出发,结合我国北方气候特点、水资源情况,分析了我国北方发展旱稻的可行性及其广阔的发展前景。     

灌浆期干旱胁迫对水稻生理性状和产量的影响

目的 研究灌浆期干旱对不同类型水稻叶片生理性状和产量的影响,为干旱气候条件下水稻栽培提供参考。方法 以节水抗旱稻旱优113和普通杂交稻扬两优6号(YLY6)为材料,设置传统淹水灌溉、灌浆期干旱胁迫两个处理,分别测定水稻的产量及产量构成、稻米品质(加工品质、外观品质和营养品质)、干物质生产及分配、叶片生理活性(叶片水势、气叶温差和光合速率)等。结果 与传统淹水灌溉相比,灌浆期干旱胁迫下水稻叶片水势、气叶温差均显著下降,最终导致叶片光合速率降低;但是在复水后2~15 d,叶片的各生理指标可以得到恢复,与对照没有显著差异;水稻产量没有明显变化,产量的稳定主要得益于前期充足的干物质积累使籽粒充分灌浆,结实率显著升高;稻米的碾磨品质没有显著影响,但扬两优6号的外观品质显著降低,却改善了旱优113的外观品质。同时,蛋白质含量升高在一定程度上改善了稻米营养品质。结论 水稻灌浆期适度干旱可以在稳定产量的基础上改善稻米品质。因此,适当在生育后期阶段减少水分的投入,不仅可节约农业用水,稳定籽粒产量,还有利于稻米品质的改善。     

Development of drought-resistant cultivars using physiomorphological traits in rice

Drought is a major problem for rice grown under rainfed lowland and upland conditions, but progress in breeding to improve drought resistance has been slow. This paper describes patterns of water-stress development in rice fields, reviews genetic variation in physio-morphological traits for drought resistance in rice, and suggests how knowledge of stress physiology can contribute to plant breeding programmes that aim to increase yield in water-limiting environments. To provide a basis for integrating physiological research with plant-breeding objectives we define drought resistance in terms of relative yield of genotypes. Therefore, a drought-resistant genotype will be one which has a higher grain yield than others when all genotypes are exposed to the same level of water stress.A major reason for the slow progress in breeding for drought resistance in rice is the complexity of the drought environment, which often results in the lack of clear identification of the target environment(s). There is a need to identify the relative importance of the three common drought types; early-season drought which often causes delay in transplanting, mild intermittent stress which can have a severe cumulative effect, and late stress which affects particularly late-maturing genotypes. In addition, in rainfed lowland rice, flooded and non-flooded soil conditions may alternate during the growing season, and affect nutrient availability or cause toxicity.Several drought-resistance mechanisms, and putative traits which contribute to them, have been identified for rice; important among these being drought escape via appropriate phenology, root characteristics, specific dehydration avoidance and tolerance mechanisms, and drought recovery. Some of these mechanisms/traits have been shown to confer drought resistance and others show potential to do so in rice. The most important is the appropriate phenology which matches crop growth and development with the water environment. A deep root system, with high root length density at depth is useful in extracting water thoroughly in upland conditions, but does not appear to offer much scope for improving drought resistance in rainfed lowland rice where the development of a hard pan may prevent deep root penetration. Under water-limiting environments, genotypes which maintain the highest leaf water potential generally grow best, but it is not known if genotypic variation in leaf water potential is solely caused by root factors. Osmotic adjustment is promising, because it can potentially counteract the effects of a rapid decline in leaf water potential and there is large genetic variation for this trait. There is genotypic variation in expression of green leaf retention which appears to be a useful character for prolonged droughts, but it is affected by plant size which complicates its use as a selection criterion for drought resistance.There is a general lack of drought related research for rice in rainfed lowland conditions. This needs to be rectified, particularly considering their importance relative to upland conditions in Asian countries. We suggest that focussing physiological-genetic research efforts onto clearly defined, major target environments should provide a basis for increasing the relevance of stress physiology and the efficiency of breeding programmes for development of drought-resistant genotypes.     

开花灌浆期干旱胁迫对水、陆稻细胞膜透性和产量性状的影响

 在开花灌浆期对三个水、陆稻品种进行干旱胁迫处理。结果发现,叶片中自由水含量较高的湘粳2号（粳型水稻）在复水后细胞膜透性仍然较高,束缚水含量下降,平均减产幅度最小,表现出明显的耐旱特性。而湘中籼3号（籼型水稻）的表现相反,是不耐旱品种。陆稻品种奉爱的抗旱性明显较强,但产量较低,有待进一步改良。     

Drought Resistance Improvement in Rice: An Integrated Genetic and Resource Management Strategy

Abstract

Drought is the major constraint to rice production in rainfed areas across Asia and sub-Saharan Africa. In the context of current and predicted water scarcity, increasing irrigation is generally not a viable option for alleviating drought problems in rainfed rice-growing systems. It is therefore critical that genetic management strategies for drought focus on maximum extraction of available soil moisture and its efficient use in crop establishment and growth to maximize biomass and yield. Extensive genetic variation for drought resistance exists in rice germplasm. However, the current challenge is to decipher the complexities of drought resistance in rice and exploit all available genetic resources to produce rice varieties combining drought adaptation with high yield potential, quality, and resistance to biotic stresses. The strategy described here aims at developing a pipeline for elite breeding lines and hybrids that can be integrated with efficient management practices and delivered to rice farmers. This involves the development of high-throughput, high-precision phenotyping systems to allow genes for yield components under stress to be efficiently mapped and their effects assessed on a range of drought-related traits, and then moving the most promising genes into widely grown rice mega-varieties, while scaling up gene detection and delivery for use in marker-aided breeding.     

Genetic analysis and validation of quantitative trait loci associated with reproductive-growth traits and grain yield under drought stress in a doubled haploid line population of rice (Oryza sativa L.)

Drought is a major constraint for rice production and yield stability in rainfed ecosystems, especially when it occurs during the reproductive stage. Combined genetic and physiological analysis of reproductive-growth traits and their effects on yield and yield components under drought stress is important for dissecting the biological bases of drought resistance and for rice yield improvement in water-limited environments. A subset of a doubled haploid (DH) line population of CT9993-5-10-1-M/IR62266-42-6-2 was evaluated for variation in plant water status, phenology, reproductive-growth traits, yield and yield components under reproductive-stage drought stress and irrigated (non-stress) conditions in the field. Since this DH line population was previously used in extensive quantitative trait loci (QTLs) mapping of various drought resistance component traits, we aimed at identifying QTLs for specific reproductive-growth and yield traits and also to validate the consensus QTLs identified earlier in these DH lines using meta-analysis. DH lines showed significant variation for plant water status, reproductive-growth traits, yield and yield components under drought stress. Total dry matter, number of panicles per plant, harvest index, panicle harvest index, panicle fertility, pollen fertility, spikelet fertility and hundred grain weight had significant positive correlations with grain yield under drought stress. A total of 46 QTLs were identified for the various traits under stress and non-stress conditions with phenotypic effect ranging from 9.5 to 35.6% in this study. QTLs for panicle exsertion, peduncle length and pollen fertility, identified for the first time in this study, could be useful in marker-assisted breeding (MAB) for drought resistance in rice. A total of 97 QTLs linked to plant growth, phenology, reproductive-growth traits, yield and its components under non-stress and drought stress, identified in this study as well as from earlier published information, were subjected to meta-analysis. Meta-analysis identified 23 MQTLs linked to plant phenology and production traits under stress conditions. Among them, four MQTLs viz., 1.3 for plant height, 3.1 for days to flowering, 8.1 for days to flowering or delay in flowering and 9.1 for days to flowering are true QTLs. Consensus QTLs for reproductive-growth traits and grain yield under drought stress have been identified on chromosomes 1 and 9 using meta-QTL analysis in these DH lines. These MQTLs associated with reproductive-growth, grain yield and its component traits under drought stress could be useful targets for drought resistance improvement in rice through MAB and/or map-based positional analysis of candidate genes.     

Yield response of rice (Oryza sativa L.) genotypes to drought under rainfed lowlands: 2. Selection of drought resistant genotypes

Drought frequently reduces grain yield of rainfed lowland rice. A series of experiments were conducted in drought-prone northeast Thailand to study the magnitude and consistency of yield responses of diverse, rainfed lowland rice genotypes to drought stress environments and to examine ways to identify genotypes that confer drought resistance. One hundred and twenty-eight genotypes were grown under non-stress and four different types of drought stress conditions. The relationship of genotypic variation in yield under drought conditions to genetic yield potential, flowering time and flowering delay, and to a drought response index (DRI) that removed the effect of potential yield and flowering time on yield under stress was examined.Drought stress that developed prior to flowering generally delayed the time of flowering of genotypes, and the delay in flowering was negatively associated with grain yield, fertile panicle percentage and filled grain percentage. Genotypes with a longer delay in flowering time had extracted more water during the early drought period, and as a consequence, had higher water deficits. They were consistently associated with a larger yield reduction under drought and in one experiment with a smaller DRI. Genotypes, however, responded differently to the different drought stress conditions and there was no consistency in the DRI estimates for the different genotypes across the drought stress experiments. The results indicate that with the use of irrigated-control and drought test environments, genotypes with drought resistance can be identified by using DRI or delay in flowering. However, selections will differ depending on the type of drought condition. The inconsistency of the estimates in DRI and flowering delay across different drought conditions reflects the nature of the large genotype-by-environment interactions observed for grain yield under various types of drought in rainfed lowland conditions.