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1.
为了明确外源激素诱导水稻抗旱性的效果及其生理机制。以中嘉早17为材料,分析外源激素在淹水灌溉、干湿交替灌溉和干旱灌溉方式下叶绿素荧光参数的差异及其对产量与产量构成的影响。结果表明,干旱灌溉显著降低了叶片光系统Ⅱ(PSⅡ)最大光化学量子产量、实际光量子效率、非光化学猝灭值、有效穗数、每穗粒数、结实率,孕穗期比分蘖期更为敏感,表现为相同胁迫时间下最大光化学量子产量、每穗粒数、单株穗数等下降更显著。赤霉素(gibberellin,GA3)处理后降低了PSⅡ最大光化学量子产量、非光化学猝灭和光化学猝灭系数,导致有效穗数减少、千粒重和结实率降低。脱落酸(abscisic acid,ABA)处理能缓解孕穗期干旱胁迫,减轻水稻叶片的光抑制程度,提高叶绿素荧光参数,增强抗旱能力。综合来看,以分蘖期淹水条件下结合IBA处理产量最高,比对照增产7.4%,这可能与淹水条件下吲哚丁酸(indolebutyric acid,IBA)处理能提高光合效率有关。  相似文献   

2.
杂交水稻结实率的研究   总被引:2,自引:0,他引:2  
对杂交水稻常规水稻在结实期间剑叶和谷粒中的蔗糖含量的变化,穗上不同部位的结实情况,实粒率和千粒重的动态变化以及它们之间的关系,结实率对有机营养供应变化的反应等方面进行了比较研究。结果表明,杂交水稻结实率较低主要是由于穗的中、下部尤其是稳下部出现较多的秕粒造成的;与常规水稻比较,杂交水稻在灌浆的前中期,剑叶和籽粒中的蔗糖含量高,籽粒增重快,后期则相反;穗上部和下部的结实率和千粒重皆差异大;在实粒增加过程中,千粒重与常规水稻相同时,实粒率低,在灌浆后期,实粒率对有机营养应给的变化较敏感,早、晚季及“库”“源”关系变化时,结实率和千粒重的变化幅度大。本文还对杂交水稻结实率较低和较不稳定的原因进行了探讨。  相似文献   

3.
中国骨干玉米自交系抗旱性分析与评价   总被引:2,自引:0,他引:2  
在新疆典型干旱、半干旱地区,通过玉米自交系的14个主要产量性状对干旱胁迫的响应特征进行分析,用主成分分析法筛选其抗旱性的主要鉴定指标,并采用抗旱系数和抗旱指数对自交系的抗旱性进行聚类分析,综合评价47份自交系的抗旱性。结果显示:(1)干旱导致玉米自交系株高、穗位高、叶绿素含量降低,果穗短小,秃尖增大,穗行数和行粒数减小,千粒重和穗粒重降低,最终造成产量下降。(2)各自交系抗旱性强弱与干旱条件下的穗粒重、穗粗、行粒数、千粒重、株高、穗位高、穗长、秃尖长、穗行数、叶绿素含量等性状具有较密切的关系,其中抗旱性表现较好的自交系是掖52106、英64、478等,其次是Mo17Ht、Mo17、丹340、郑58、X178、C103等。研究表明,在育种实践中,田间自交系抗旱性筛选应以穗粒重、穗粗、行粒数、千粒重、株高、穗位高、穗长、秃尖长、穗行数、叶绿素含量等为主要指标,并结合产量抗旱系数、抗旱指数对自交系抗旱性进行综合评价。  相似文献   

4.
东乡野生稻回交重组系的抗旱性评价体系   总被引:2,自引:0,他引:2  
选用协青早B//东乡野生稻/协青早B回交重组系及其亲本共79份水稻材料,研究了水稻发芽期、苗期、孕穗期、成熟期的种子萌发抗旱指数等31个指标与东乡野生稻回交重组系抗旱性的关系.结果表明:15% PEG-6000溶液处理的相对发芽势、20% PEG-6000溶液处理的种子萌发抗旱指数和相对发芽势及水分胁迫后最长根长、苗高、根鲜质量、根干质量、根系相对含水量、萎蔫率、叶片可溶性糖含量、叶片脯氨酸含量、叶片丙二醛含量、叶片相对含水量、卷叶级别、株高、单株分蘖数、单株有效穗数、穗实粒数、着粒密度、结实率、千粒重等21个指标的相对值与抗旱系数或抗旱指数的相关性显著.通过逐步回归分析筛选出9个抗旱性鉴定指标:20% PEG-6000溶液处理的相对发芽势及水分胁迫后根干质量、根系相对含水量、叶片可溶性糖含量、叶片脯氨酸含量、叶片丙二醛含量、单株有效穗、结实率和千粒重的相对值.根据这些指标和偏相关系数,建立了不同时期的抗旱性评价(D值)方程和评价体系,可对东乡野生稻回交重组系抗旱性进行较好的评价.  相似文献   

5.
河北省冬小麦丰产抗旱性表型鉴定指标分析   总被引:2,自引:0,他引:2  
以河北省审定的85个冬小麦品种为材料,采用防雨棚春季干旱和露地灌溉2个处理,分别于开花期、成熟期调查株高等27个表型性状,分析了各表型性状与单株子粒产量的相关性。结果表明,单株成穗数等12个性状与单株子粒产量抗旱系数或抗旱指数呈显著或极显著相关;结合表型性状变异系数,明确了提高单株成穗数、穗粒数、灌溉条件下较长的旗叶长度和干旱条件下较短的旗叶长度是培育丰产抗旱小麦新品种的主攻方向;子粒比重、子粒长度及干旱条件下的结实率和每穗小穗数可作为河北省小麦种质资源丰产抗旱性的鉴定依据;河北省小麦品种丰产性高,而抗旱性尚需进一步改善。  相似文献   

6.
东乡普通野生稻与栽培稻苗期抗旱性的比较   总被引:4,自引:0,他引:4  
干旱影响水稻生长发育,不论什么时期发生最终都导致产量损失。研究水稻资源抗旱性有助于水稻抗旱改良和稳定干旱胁迫下水稻的产量。东乡普通野生稻被公认为是栽培稻的祖先,对增强水稻抗旱性可能十分重要。对4份来自3个仅存的居群的东乡野生稻与15份栽培稻进行苗期抗旱性比较,考察了3次重复的盆栽土培试验中8个抗旱指标。表明东乡普通野生稻比栽培稻更为抗旱,表现在最大根长、茎长、根干重、根鲜重、根干鲜重比及抗旱指数等6个性状,而不表现在根数及根茎长比;其中茎长、最长根长、根干重、根鲜重及根系相对含水量对水稻苗期抗旱性影响更大。采用抗旱指数和抗旱总级别值法对水稻抗旱性进行评定,结果表明4份东乡野生稻材料间的抗旱性存在很大差异,且来水桃树下居群的抗性最高,东乡野生稻抗旱性可能与其原生境状况有关。结果认为东乡普通野生稻可作为栽培稻抗旱改良的遗传资源。  相似文献   

7.
干旱是水稻生产中最严重的非生物胁迫,增强根系对深层土壤水分的吸取能力是提高水稻抗旱性的重要育种目标。为筛选优异抗旱稻种资源,本研究对2234份栽培稻种质资源进行了以深根比为鉴定指标的避旱性鉴定评价,在水分梯度抗旱大棚中对131份具有不同深根比的种质进行了孕穗期抗旱性鉴定评价。供试材料的深根比变异范围为8.6%~60.1%,平均深根比为25.8%,47.2%材料的深根比集中在20%~30%之间,25.2%材料的深根比低于20%,深根比超过40%的高深根比种质仅占6.1%;国外材料中高深根比种质比例达到了24.4%,其次是上海(17.9%)和湖南(15.6%),广东、贵州和广西的高深根比种质比例均低于1%;地方品种的深根比略高于育成品种(系),地方品种的高深根比种质比例也高于育成品种(系);粳稻深根比高于籼稻深根比,粳稻中高深根比种质比例是籼稻的3.6倍;在籼稻种质中,湖南籼稻材料中高深根比种质比例较高,而广东、广西和贵州等省的籼稻种质中都只有1份高深根比种质。孕穗期抗旱性鉴定结果显示,高深根比种质中的高抗旱材料比例是低深根比材料的3.2倍、是中等深根比材料的2.0倍。综合分析干旱胁迫和正常水分条件下的结实率以及两种情况下的每穗粒数比值和结实率比值等抗旱性鉴定指标,筛选获得26份抗旱性优异材料,可作为水稻节水抗旱育种优良亲本和应用于抗旱基因挖掘。  相似文献   

8.
在大田条件下,以转基因抗虫水稻Bt63、R1和R2及非转基因水稻汕优63(对照)为材料,设置高、低两种虫压环境条件,研究虫压胁迫对转Bt抗虫基因水稻生长发育及产量相关性状的影响.结果表明:抗虫水稻在虫压胁迫条件下可充分体现出外源基因的抗性特点.在高虫压条件下,3种转Bt基因水稻受螟虫危害程度远低于对照植株,株高、分蘖数、地上部鲜质量、穗长、穗质量、单株穗数、单株实粒数、实粒质量、结实率、千粒重等生长发育和产量指标均高于对照,但仅株高、分蘖数和穗长3个指标与对照有显著差异.因此,抗虫外源Bt基因的引入对水稻结实性不会产生负面效应,高虫压胁迫条件对抗虫转基因水稻产量的影响较小.  相似文献   

9.
为了鉴定陆地棉的抗旱性与丰产性,在年降雨量不足40 mm的敦煌市,设干旱胁迫和正常灌溉两个处理,通过测定102份棉花品种的15个形态与产量指标,应用相关分析的方法确定抗旱指标,采用直接抗旱鉴定评价法与综合抗旱鉴定法对其进行抗旱性评价,结果显示,棉花抗旱性综合评价应选择年际间变异较小的单铃重、株高、主茎节间长度、果枝数、单株铃数、单株产量和茎干重7个指标,基于这7个单项指标计算的综合抗旱性评价指标之间相关性较高,都能评价棉花品种的抗旱性,抗旱丰产棉花种质的筛选需要综合考虑多种因素的影响,在综合评价品种抗旱性的基础上,结合单株籽棉产量计算的改进抗旱指数和抗旱系数,可筛选出抗旱丰产品种金垦1号和金垦108,不抗旱丰产品种中21371、巴西012、石远321、冀丰1056和新陆早33号,两年鉴定结果一致,品种抗旱丰产性表现稳定,适合西北内陆棉区种植,可作为抗旱鉴定标准品种。  相似文献   

10.
小麦品种抗旱性评价指标研究   总被引:6,自引:0,他引:6  
以抗旱性不同的冬小麦品种为材料,在正常降雨年型的干旱处理(DT)和正常灌溉(CK)条件下,对于不同类型抗旱品种的产量形成能力、抗旱性评价指标以及相关抗旱生理参数进行了较全面的研究。结果表明,可采用抗旱指数(DRI)和产量降低指数(YDI)作为评价小麦品种抗旱性强弱的指标。供试品种成熟期单株干物重具有较大的差异,表现为随着品种抗旱性的增强而不断增加,表明干旱条件下单株干物重的大小与小麦品种的抗旱性具有密切联系。研究发现,单位面积穗数与产量降低指数的相关达到极显著水平,表明在干旱条件下单位面积具有较多的穗数形成能力,对于干旱条件下小麦获得相对较高的产量具有重要作用。旗叶全展、中期和生长后期的净光合速率(Pn)和脯氨酸含量均与抗旱指数和产量降低指数、叶绿素含量与产量降低指数分别呈显著或极显著相关,表明可用植株旗叶的Pn、叶绿素含量和脯氨酸含量作为评价小麦品种抗旱性强弱的参考生理指标。  相似文献   

11.
Water deficit is a serious environmental stress and the major constraint to rice productivity. Losses in rice yield due to water shortage probably exceed losses from all other causes combined and the extent of the yield loss depends on both the severity and duration of the water stress. Drought affects rice at morphological, physiological, and molecular levels such as delayed flowering, reduced dry matter accumulation and partitioning, and decreased photosynthetic capacity as a result of stomatal closure, metabolic limitations, and oxidative damage to chloroplasts. Small-statured rice plants with reduced leaf area and short growth duration are better able to tolerate drought stress, although the mechanisms are not yet fully understood. Increased water uptake by developing larger and deeper root systems, and the accumulation of osmolytes and osmoprotectants are other important mechanisms for drought resistance. Drought resistance in rice has been improved by using plant growth regulators and osmoprotectants. In addition, several enzymes have been found that act as antioxidants. Silicon has also improved drought resistance in rice by silicification of the root endodermis and improving water uptake. Seed priming improves germination and crop stand establishment under drought. Rice plants expressing HVA1, LEA proteins, MAP kinase, DREB and endo-1, 3-glucanase are better able to withstand drought stress. Polyamines and several enzymes act as antioxidants and reduce adverse effects of drought stress in rice. Drought resistance can be managed by developing and selecting drought-tolerant genotypes. Rice breeding and screening may be based on growth duration, root system, photosynthesis traits, stomatal frequency, specific leaf weight, leaf water potential, and yield in target environments. This review discusses recent developments in integrated approaches, such as genetics, breeding and resource management to increase rice yield and reduce water demand for rice production.  相似文献   

12.
Drought resistance of rice is a complex trait and is mainly determined by mechanisms of drought avoidance and drought tolerance. The present study was conducted to characterize the genetic basis of drought resistance at reproductive stage in field by analyzing the QTLs for drought response index (DRI, normalized by potential yield and flowering time), relative yield, relative spikelet fertility, and four traits of plant water status and their relationships with root traits using a recombinant inbred population derived from a cross between an indica rice and upland rice. A total of 39 QTLs for these traits were detected with individual QTL explained 5.1–32.1% of phenotypic variation. Only two QTLs for plant water status were commonly detected in two environments, suggesting different mechanisms might exist in two types of soil conditions. DRI has no correlation with potential yield and flowering time under control, suggesting that it can be used as a good drought resistance index in field conditions. The co-location of QTLs for canopy temperature and delaying in flowering time suggested a usefulness of these two traits as indexes in drought resistance screening. Correlation and QTL congruence between root traits and putative drought tolerance traits revealed that drought avoidance (via thick and deep root traits) was the main genetic basis of drought resistance in sandy soil condition, while drought tolerance may play more role in the genetic basis of drought resistance in paddy soil condition. Therefore, both drought mechanisms and soil textures must be considered in the improvement of drought resistance at reproductive stage in rice.  相似文献   

13.
Involvement of polyamines in the drought resistance of rice   总被引:2,自引:0,他引:2  
This study investigated whether and how polyamines (PAs) in rice (Oryza sativa L.) plants are involved in drought resistance. Six rice cultivars differing in drought resistance were used and subjected to well-watered and water-stressed treatments during their reproductive period. The activities of arginine decarboxylase, S-adenosyl-L-methionine decarboxylase, and spermidine (Spd) synthase in the leaves were significantly enhanced by water stress, in good agreement with the increase in putrescine (Put), Spd, and spermine (Spm) contents there. The increased contents of free Spd, free Spm, and insoluble-conjugated Put under water stress were significantly correlated with the yield maintenance ratio (the ratio of grain yield under water-stressed conditions to grain yield under well-watered conditions) of the cultivars. Free Put at an early stage of water stress positively, whereas at a later stage negatively, correlated with the yield maintenance ratio. No significant differences were observed in soluble-conjugated PAs and insoluble-conjugated Spd and Spm among the cultivars. Free PAs showed significant accumulation when leaf water potentials reached -0.51 MPa to -0.62 MPa for the drought-resistant cultivars and -0.70 MPa to -0.84 MPa for the drought-susceptible ones. The results suggest that rice has a large capacity to enhance PA biosynthesis in leaves in response to water stress. The role of PAs in plant defence to water stress varies with PA forms and stress stages. In adapting to drought it would be good for rice to have the physiological traits of higher levels of free Spd/free Spm and insoluble-conjugated Put, as well as early accumulation of free PAs, under water stress.  相似文献   

14.
The progress in development and dissemination of drought tolerant lines has been slow as compared to the increasing drought prevalence in the rice growing regions. Significant amount of work has been done in the past on drought resistance traits in rice crop, still the benefit of improved drought tolerant rice cultivars reaching the farmer’s field is not very high and ways to expedite the development of drought tolerant and productive rice cultivars needs to be addressed. In this article, an assessment of easily practicable approach of managed stress screening and prospect of direct selection for yield under drought stress is discussed. Also the large effect yield QTLs identified for grain yield under drought stress field conditions is being reviewed for successful introgression into elite genetic background for developing drought tolerant cultivars with improved yield for the drought prone target environment.  相似文献   

15.
The use of molecular markers in the mapping of traits of agronomic importance holds great promise for speeding the development of improved plant varieties and increasing our understanding of the physiological or molecular mechanisms behind biological phenomena. The technique is now being applied to drought resistance in rice (Oryza sativa L.). Drought is important because a considerable proportion of the world rice area is not irrigated and can be prone to water deficit. A large number of people, particular some of the poorest rice farmers, stand to gain if new varieties which combine high yield and drought resistance can be developed. Rice should be particularly useful for the molecular genetic analysis of drought resistance because of its growing role as a model monocot species and the diversity of drought resistance mechanisms which are found in the germplasm. We briefly review the traits which might be considered important in improving drought resistance in rice, before explaining the molecular mapping approach. We review progress at locating quantitative trait loci (QTLs) for individual mechanisms of drought resistance in controlled environment conditions. This includes a detailed comparison of reported QTLs related to root morphological characters. The search for QTLs associated with field performance under drought stress is analysed and the problems associated with understanding the genetic control of a complex physical and physiological phenomenon under conditions of substantial environmental variation are highlighted. We emphasise that the use of near isogenic lines in overcoming some of the problems offers considerable promise for the future.(seconded from CIRAD-CA, France)  相似文献   

16.
17.
Late season drought coinciding with the rice booting to heading stage affects the development of plant height,panicle exsertion,and flag leaf size,and causes significant yield loss.In this study,a recombinant inbred line population derived from a cross between paddy and upland cultivars was used for data collection of the morphologic traits under well water and drought stress conditions.bought stress was applied at the stage of panicle initiation in the field in 2002 and at the booting stage in PVC pipes in 2003.The data from stress con ditions and their ratios(tait measured under stress condition/trait measured under well water condition)or differences(trait measured under stress condition minus trait measured under well water condition)were used for OTL analysis.Totally,17 and 36 QTLs for these traits were identified in 2002 and 2003,respectively,which explained a range of 2.58%-29.82%Of the phenotypic variation.Among them,six QTLs were commonly identified in the two years,suggesting that the drought stress in the two years was different.The genetic basis of these traits will provide useful information for improving rice late season drought resistance,and their application as indirect indices in rice late season drought resistance screening was also discussed.  相似文献   

18.
19.
Drought is a major abiotic stress limiting rice production and yield stability in rainfed ecosystems. Identifying quantitative trait loci (QTL) for rice yield and yield components under water limited environments will help to develop drought resilient cultivars using marker assisted breeding (MAB) strategy. A total of 232 recombinant inbred lines of IR62266/Norungan were used to map QTLs for plant phenology and production traits under rainfed condition in target population of environments. A total of 79 QTLs for plant phenology and production traits with phenotypic variation ranging from 4.4 to 72.8% were detected under non-stress and drought stress conditions across two locations. Consistent QTLs for phenology and production traits were detected across experiments and water regimes. The QTL region, RM204-RM197-RM217 on chromosome 6 was linked to days to 50% flowering and grain yield per plant under both rainfed and irrigated conditions. The same genomic region, RM585-RM204-RM197 was also linked to harvest index under rainfed condition with positive alleles from Norungan, a local landrace. QTLs for plant production and drought resistance traits co-located near RM585-RM204-RM197-RM217 region on chromosome 6 in several rice genotypes. Thus with further fine mapping, this region may be useful as a candidate QTL for MAB, map-based cloning of genes and functional genomics studies for rainfed rice improvement.  相似文献   

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