水稻产量库相关穗部性状的遗传分析

收人李源于珍汕97/明恢63的重组系群体中与产量库容有关的10个穗部性状的表现型数据。总体上,每穗颖花数与每穗二次枝梗数、每个二次枝梗上的颖花数、颖花密度有更大的相关性。对所研究的10个性状,两年间共检测到53个QTLs。约43.4%的QTLs能在两年同时检测到。5个染色体区域（第1染色体上G359-RG532和C567-C86-RG236,第2染色体上R712-RM29,第6染色体上P-RG424,第10染色体上C148-RM258）分别对多个穗部性状表现出效应。结果显示相关性状的QTLs大致定位在相似的染色体区域,这表明基因的多效性或紧密连锁是穗部性状间相关的遗传基因。在检测到的大量2位点互作对中,约18.2%在两年都能被检测到。不同性状的共同互作对的比例为8.7%～32.6%。在两年都能检测到2位点组合中,约26.7%的组合同时影响着多个性状,表现出多效效应。结果表明每个性状都由数个QTL、基因型与环境互作、大量的上位性互作所控制。     

水稻加工品质数量性状基因座 (QTLs)分子定位研究

检测了Lemont/特青RI群体212个株系的糙米率（BR）,精米率（MR）和整精米率（HR）等3项加工品质性状,利用RFLP连锁图和线性模型的复合区间作图方法（QTLMapperV1.0)进行QTL定位研究。群体呈边境分布,双向超亲现象明显,HR较BR,MR变异范围更大并偏向低值方向;分别检测到1个MR,4个HR主效QTL,其中QHr6和QHr7等2个基因座具有较大遗传效应;分别检测到12对影响BR、5对影响MR,16对影响HR的上位性基因座,上位性效应的影响大于主效QTLs,不同性状或同一性状上位性效应通过共同的区间形成复杂的互相联系。     

Critical Yield Factors for Achieving High Grain Yield in Early-Season Rice Grown under Mechanical Transplanting Conditions

Double-season rice cropping systems occupy a large portion of the rice production area in southern China. Because the problem of insufficient labor, mechanical transplanting (in contrast to the manual transplanting) was become more attractive in double-season rice system. However, the decisive yield factors which resulting in high grain yield of early-season rice are unclear under mechanical-transplanted conditions. In present study, the field experiments were conducted in the early season in 2017 and repeated in 2018 in Santang Town, Hunan Province, China. Ten early season rice cultivars (Zhuliangyou 819, Lingliangyou 268, Lingliangyou 104, Luliangyou 996, Xiangzaoxian 24, Xiangzaoxian 32, Xiangzaoxian 45, Xiangzaoxian 42, Zhongjiazao 17, and Zhongzao 39) were used as materials in this study. The difference in grain yield and closelyrelated agronomic and physiological traits of ten tested cultivars were compared. The range of yields (t ha^–1 at 86% dry matter) in 2017 was 6.2 to 8.7 (mean 7.8) and in 2018 was 6.5 to 8.4 (mean 7.8). Grain weight and pre-heading biomass accumulation had potent significant positive correlations with the grain yield. The greater pre-heading biomass accumulation was major attributed to higher apparent radiation use efficiency. Our results suggested that early-season rice cultivars to achieve the high grain yield in mechanical-transplanted conditions depends on apparent radiation use efficiency in the pre-heading period and higher grain weight.     

水稻产量数量性状的遗传调控机制研究进展

粒重、每穗粒数和每株穗数是决定水稻产量的三大要素,也是水稻育种改良的重点．这些性状都是遗传复杂的数量性状．近十年来,水稻数量性状遗传学领域取得了突破性的进展,成功克隆了一批控制水稻产量性状的数量性状位点（QTL）．本文将简要介绍产量性状相关QTL的功能与作用机制．这些研究成果不仅有助于揭示产量性状形成的遗传基础,也将有力推动水稻分子设计育种的进程．     

水稻产量相关QTL研究现状

产量是最为复杂的数量性状,对它的遗传机理了解甚微。近15年来,许多学者利用随机分离群体定位了许多影响水稻产量及其组分的QTL,即以QTL定位的方法对产量潜力进行遗传剖析。试验证明上位性效应对产量及其组分性状遗传变异起着重要作用,但目前大多数QTL研究仍侧重于发掘和克隆单个主效QTL,然而对单一基因／QTL的深入了解还不足以诠释复杂性状遗传基础的全貌,还没有为育种家提供足够的可应用于分子标记辅助育种的遗传信息并用于提高水稻产量。笔者认为今后的数量性状研究尚需加强复杂性状QTL遗传网络的发掘,在改良水稻品种性状的同时发展并完善QTL研究。     

水稻生物学产量及其构成性状的QTL定位

QTL的加性效应、加性×加性上位性效应及它们与环境的互作效应是数量性状的重要遗传分量.利用IR64/Azucena的125个DH品系为群体,分析了水稻生物学产量及其两个构成性状干草产量和谷粒产量的遗传组成.用基于混合模型的复合区间作图(MCIM)方法进行QTL定位.检测到12个位点有加性主效应,27个位点涉及双位点互作,18个位点存在环境互作.结果表明水稻生物学产量和它的两个构成性状普遍存在上位性效应和QE互作效应.此外,还探讨了性状间相关的遗传基础.发现4个QTLs和一对上位性QTLs可能与生物学产量与干草产量之间的正相关有关.3个QTL可能与干草产量与谷粒产量之间的负相关有关.这些结果可能部分地解释了这3个性状相关的遗传原因.通过对水稻生物学产量及其两个构成性状所定位QTL的分析,加深了对数量性状QTL的认识.首先,QTL的上位性效应和QE互作效应是普遍存在的;其次,QTL的多效性或紧密连锁可能是遗传相关的原因,当QTL对两个性状作用的方向相同时可导致正向遗传相关,反之则为负向遗传相关,当有些QTL表现为同向作用而另一些QTL表现为反向作用时,则可削弱性状间的遗传相关性;第三,复合性状的QTL效应可分解为其组成性状的QTL效应,如果QTL对各组成性状的效应方向相反而相互抵消,可使复合性状的QTL效应不易被检测;第四,加性效应的QTL常参预构成上位性效应,而具有上位性效应的QTL并非都有加性主效应,表明忽略上位性的QTL定位方法会降低检测QTL的功效;最后,鉴别不同类型的QTL效应有利于指导育种实践,选择主效QTL适用于多环境,QE互作QTL适用于特定环境,对上位性QTL应强调选择基因组合而并非单个基因.     

Identification of a Drought Tolerant Introgression Line Derived from Dongxiang Common Wild Rice (O. rufipogon Griff.)

Construction of introgression lines using cultivated rice as recipient and wild rice is a novel approach to explore primitive and broad genetic resources in rice breeding. We recently generated a set of 159 introgression lines via a backcrossing program using an elite Indica cultivar rice Guichao 2 (O. sativa L. ssp. indica) as recipient and a common wild rice Dongxiang accession (O. rufipogon Griff.) as donor. In this study, we have evaluated the previously constructed 159 introgression lines for drought-tolerance. A total of 12 quantitative trait loci (QTLs) related to drought tolerance were mapped. Furthermore, a drought tolerant introgression line, IL23, was identified and characterized. Genotype analysis of IL23 demonstrated that IL23 contained two QTLs associated with drought tolerance, qSDT2-1 and qSDT12-2, which were located on chromosome 2 and 12 within the two introgressed segments derived from the common wild rice, respectively. Physiological characterization, including measurement of water loss, osmotic potential, electrolytical leakage, MDA content, soluble sugars content and the leaf temperature, revealed that IL23 showed the characteristics associated with drought tolerance. Identification and characterization of IL23 would provide a useful basis for isolation of novel genes associated with drought tolerance and for molecular breeding of drought tolerant rice. Furthermore, the results in this study indicated that construction of introgression lines from common wild rice should be an appropriate approach to obtain favorable genetic materials.     

栽培稻旱胁迫叶片相关性状的遗传解析

利用籼稻窄叶青8号(ZYQ8)和粳稻京系17(JX17)衍生的加倍单倍体(DH)群体127个株系,2002年在杭州采用田间断水法栽培,在水分胁迫下,对叶片的卷叶、相对含水量和电导率3个性状进行了评价和QTL分析。结果表明,3个性状在DH群体中均存在双向超亲分离,接近正态分布,受数量性状基因的控制;检测到影响这些性状的6个QTL,其中卷叶3个(qLR—1,qLR—5和qLR—11)、相对含水量2个(qRWC—1和qRWC—6和电导率1个(qERC—6）。旱胁迫时,目测卷叶方便易行,适于对大批品种或资源筛选,对抗旱栽培稻品种的筛选和利用具有一定的指导意义。     

穗颈维管性状与产量相关性状的遗传分析

穗颈维管性状是实现"源"合成的同化物输送至籽粒中的唯一通道.本研究利用来源于籼稻93-11(受体)和粳稻日本晴(供体)构建的染色体片段代换系群体,调查穗颈维管性状与穗部产量性状.结果表明,大部分穗颈维管性状与穗部产量性状呈显著相关;7个穗颈维管性状共检测到42个QTL,其中16个位点日本晴等位基因起增效作用;6个穗部产...     

超级杂交水稻谷粒产量与叶光合速率的关系

在2000～2005年期间,通过测定几种超级杂交水稻与普通杂交水稻‘汕优63’的产量构成和叶片光合作用探讨了谷粒产量与光合作用的关系。结果表明:(1)4种超级杂交水稻‘培矮64S/E32’、‘P88S/O293’、‘金23A/611’和‘GD-lS/ RB207’的产量水平显著高于‘汕优63’,是对照的108%～120%。(2)与‘汕优63’相比,这些超级杂交水稻的株型好,上层叶片直立,穗大即每穗粒数多,是对照的125%～177%。(3)与‘汕优63’相比,这些组合第二叶的净光合速率显著提高,但第一叶即剑叶的未必都较高。(4)去半叶处理降低了‘GD-1S/RB207’的结实率,而去半穗处理显著提高了结实率。因此,这些超级杂交水稻的高产原因在于穗大、株型好以及群体光能利用效率高。增加单叶特别是剑叶的光合能力是克服谷粒产量的光合产物源限制和在未来的超级杂交水稻育种中实现产量潜力新突破的关键。     

水稻米粒延伸性的遗传剖析

以籼稻ZYQ8与粳稻JX17为亲本的DH群体作为研究材料,考察DH群体及双亲的米粒延伸率相关性状,并使用该群体的分子连锁图谱进行QTL分析.共检测到14个与稻米延伸性有关的QTL,包括2个粒长QTL、7个饭粒长QTL和5个米粒延伸率QTL,分别位于第1、2、3、5、6、7、10、11和12染色体.所有QTL的LOD值介于2.26～9.25,分别解释性状变异的5.31%～17.21%.在第3染色体上的G249～G164、第6染色体上的G30～RZ516和第10染色体上的G1082～GA223区间同时检测到控制饭粒长和米粒延伸率的QTL.米粒延伸性受多基因控制,Wx基因与位于第6染色体上的qCRE-6的G30～RZ516区间相近,对米饭的延伸性具重要影响.     

水稻粒长QTL定位与主效基因的遗传分析

该研究利用短粒普通野生稻矮杆突变体和长粒栽培稻品种KJ01组配杂交组合F_1,构建分离群体F_2;并对该群体粒长进行性状遗传分析,利用平均分布于水稻的12条染色体上的132对多态分子标记对该群体进行QTL定位及主效QTLs遗传分析,为进一步克隆新的主效粒长基因奠定基础,并为水稻粒形育种提供理论依据。结果表明:(1)所构建的水稻杂交组合分离群体F_2的粒长性状为多基因控制的数量性状。(2)对543株F_2分离群体进行QTL连锁分析,构建了控制水稻粒长的连锁遗传图谱,总长为1 713.94 cM,共检测出24个QTLs,只有3个表现为加性遗传效应,其余位点均表现为遗传负效应。(3)检测到的3个主效QTLs分别位于3号染色体的分子标记PSM379～RID24455、RID24455～RM15689和RM571～RM16238之间,且三者对表型的贡献率分别为54.85%、31.02%和7.62%。(4)在标记PSM379～RID24455之间已克隆到的粒长基因为该研究新发现的主效QTL位点。     

杂交粳稻及其亲本千粒重与产量、品质的相关性

为了探明杂交粳稻及其亲本千粒重与产量、品质的关系,以4个千粒重介于23.1~28.0 g之间的BT型不育系和24个千粒重介于18.1~32.0 g之间的三系粳稻恢复系,采用p×q不完全双列杂交(NCⅡ)设计,配制96个杂交组合为试验材料,对F1千粒重优势表现、F1千粒重与亲本千粒重及其与产量、品质性状间的相关性进行分析,确定高产优质兼顾的杂交粳稻的千粒重范围。结果表明:(1)56.3%的杂交组合千粒重超过其双亲平均值,19.8%的杂交组合千粒重表现正向超亲优势;(2)F1千粒重与母本千粒重、父本千粒重、双亲千粒重平均值的相关性均达极显著水平(r=0.33**、0.71**、0.78**),且恢复系千粒重对杂种的影响大于不育系;(3)F1千粒重、父本千粒重及双亲千粒重平均值与组合单株产量的相关性均达极显著水平(r=0.55**、0.47**、0.51**),母本千粒重与组合单株产量相关不显著;(4)F1千粒重、父本千粒重与糙米率、精米率、整精米率、垩白粒率、粒长、粒宽均呈极显著正相关,与透明度呈显著正相关,母本千粒重与垩白粒率、垩白度、粒长均呈极显著正相关,与粒宽呈显著正相关;(5)杂交粳稻育种中具有高产优质兼顾的F1千粒重范围应在25.1~27.0 g之间。     

Mapping QTL for Biomass Yield and Its Components in Rice (Oryza sativa L.)

Addicive effects, additive by additive epistatic effects, and their environmental interactions of QTLs are important genetic components of quantitative traits. Genetic architecture underlying rice biomass yield and its two component traits (straw yield and grain yield) were analyzed for a population of 125 DH lines from an inter-subspecific cross of IR64/Azucena. The mixed-model based composite interval mapping approach (MCIM) was used to detect QTLs, There were 12 QTLs detected with additive main effects, 27 QTLs involved in digenic interaction with aa and/or aae effects, and 18 QTLs affected by environments with ae and/or aae effects. It was revealed that epistatic effects and QE interaction effects existed on biomass yield and its component traits in rice. In addition, the genetic basis of relationships among these traits were investigated. Four QTLs and one pair of epistatic QTLs were detected to be responsible for the positive correlation between biomass yield and straw yield. Three QTLs might be responsible for the negative correlation between straw yield and grain yield. This result could partially explain the genetic basis of correlation among the three traits, and provide useful information for genetic improvement of these traits by marker-assisted selection.     

Multi-Environmental Genetic Analysis of Grain Size Traits Based on Chromosome Segment Substitution Line in Rice (<i>Oryza sativa</i> L.)

Grain size traits are critical agronomic traits which directly determine grain yield, but the genetic bases of these traits are still not well understood. In this study, a total of 154 chromosome segment substitution lines (CSSLs) population derived from a cross between a japonica variety Koshihikari and an indica variety Nona Bokra was used to investigate grain length (GL), grain width (GW), length-width ratio (LWR), grain perimeter (GP), grain area (GA), and thousand grain weight (TGW) under four environments. QTL mapping analysis of six grain size traits was performed by QTL IciMapping 4.2 with an inclusive composite interval mapping (ICIM) model. A total of 64 QTLs were identified for these traits, which mapped to chromosomes 1, 2, 3, 4, 6, 7, 8, 10, 11, and 12 and accounted for 1.6%–27.1% of the total phenotypic variations. Among these QTLs, thirty-six loci were novel and seven QTLs were identified under four environments. One locus containing the known grain size gene, qGL3/GL3.1/OsPPKL1, also have been found. Moreover, five pairs of digenic epistatic interactions were identified except for GL and GP. These findings will facilitate fine mapping of the candidate gene and QTL pyramiding to genetically improve grain yield in rice.     

江西东乡野生稻苗期抗旱基因定位

普通野生稻是栽培稻的祖先种,其遗传多样性远远大于栽培稻,蕴涵着栽培品种中难以找到的重要性状.以江西东乡普通野生稻为供体、以桂朝2号为遗传背景的野生稻基因渗入系（BC4F5、BC4F6）为材料,利用30%的PEG人工模拟干旱环境,对渗入系二叶一心苗期进行抗旱鉴定,共定位了12个与抗旱有关的QTL,其中在第2、6和12染色体上发现了4个QTL的加性效应值为正,来自东乡野生稻的等位基因能使渗入系的抗旱性增强,特别是位于第12染色体RM17附近的qSDT12-2在多次重复中均被检测到,在PEG处理后1-8 d能稳定表达.通过对抗旱性QTL的动态分析,发现不同QTL表达时间不同.     

利用双单倍体群体剖析水稻产量及其相关性状的遗传基础

主效QTL、上位性效应和它们与环境的互作(QE)都是数量性状的重要遗传因素。利用籼粳交珍汕97／武育粳2号F1植株上的花药进行组织培养得到的190个双单倍体群体和179个微卫星标记,通过两年两重复田间试验,采用混合线性模型方法分析了9个控制水稻产量及其相关性状的遗传效应,得到57个主效QTL,41对上位性互作,8对QTL与环境的互作和7对上位性效应与环境的互作。单个主效QTL解释这些性状1．3％～25．8％的表型方差。各性状QTL的累积表型贡献率达11．5％～66．8％。大多数性状之间具有显著的表型相关性,相关性较高的性状之间常具有较多共同或紧密连锁的QTL。结果表明,基因的多效性或紧密连锁可能是性状相关的重要遗传基础。     

利用CSSLs群体研究稻米粒型QTL的表达稳定性

利用Asominori×IR2 4的染色体片段置换系 (CSSLs)群体 ,对稻米粒长、粒宽和长宽比进行连续两年及 4个地点的QTL表达稳定性分析。结果表明 :3个性状“两年四点”的表现型都为连续分布 ,均存在超亲遗传类型 ;共检测到 13个粒型相关QTL ,其中在 8个环境中都能被重复检测到的QTL有 6个 ,即影响粒长的 qGL 3、控制粒宽的qGW 5a和 qGW 5b以及共同作用于长宽比的qLWR 3、qLWR 5a和 qLWR 5b。这 6个QTL对应置换系的相应性状与背景亲本Asominori的表现型差异在 8个环境中都达到极显著水平 (P <0 0 0 1) ,且同一QTL对应置换系相应性状的表现型在不同环境间呈显著正相关 (r≥ 0 75 ,r0 0 5=0 6 6 6 ) ,说明这 6个QTL表达稳定性较高。由于 qGL 3和 qLWR 3均位于R19 C16 77标记区间 ,qGW 5a和 qLWR 5a位于C2 6 3标记附近 ,qGW 5b和 qLWR 5b被定位在R5 6 9标记附近 ,因此R19、C16 77、C2 6 3和R5 6 9这 4个RFLP标记对优良水稻外观品质的标记辅助选择 (MAS)育种有着重要作用     

Dissection of genetic overlap of salt tolerance QTLs at the seedling and tillering stages using backcross introgression lines in rice

QTLs for salt-tolerance(ST)related traits at the seedling and tillering stages were identified using 99 BC2F8 introgression lines(IL)derived from a cross between IR64(indica)as a recurrent parent and Binam(japonica)from Iran as the donor parent.Thirteen QTLs affecting survival days of seedlings(SDS), score of salt toxicity of leaves(SST),shoot K concentration(SKC)and shoot Na concentration(SNC) at the seedling stage and 22 QTLs underlying fresh weight of shoots(FW),tiller number per plant(TN) and plant height(PH)at the tillering stage were identified.Most QTLs detected at the tillering stage showed obvious differential expression to salt stress and were classified into three types based on their differential behaviors.Type I included 11 QTLs which were expressed only under the non-stress condition.Type II included five QTLs expressed in the control and the salt stress conditions,and three of them(QPh5,QPh8 and QTn9)had similar quantity and the same direction of gene effect,suggesting their expression was less influenced by salt stress.Type III included six QTLs which were detectable only under salt stress,suggesting that these QTLs were apparently induced by the stress.Thirteen QTLs affecting trait difference or trait stability of ILs between the stress and non-stress conditions were identified and the Binam alleles at all loci except QPh4,QTn2 and QFw2a decreased trait difference.The three QTLs less influenced by the stress and 13 QTLs affecting trait stability were considered as ST QTLs which contributed to ST.Comparing the distribution of QTLs detected at the seedling and tillering stages,most(69%)of them were genetically independent.Only four were the same or adjacent regions on chromosomes 1,2,8 and 11 harboring ST QTLs detected at the two stages,suggesting that partial genetic overlap of ST across the two stages occurs.It is likely,therefore,to develop ST rice variety for both stages by pyramiding of ST QTLs of different stages or selection against the overlapping QTLs between the two stages via marker-assisted selection(MAS).     

Mapping osmotic adjustment in an advanced back-cross inbred population of rice

Osmotic adjustment is one of several characters putatively associated with drought tolerance in rice. Indica cultivars are known to have a greater capacity for osmotic adjustment than japonica cultivars. We developed an advanced back-cross population using an indica donor, IR62266-42-6-2, to introgress osmotic adjustment into an elite japonica cultivar, IR60080-46A. One hundred and fifty BC₃F₃ families were genotyped using microsatellites and RFLP markers, and a few candidate genes. We evaluated osmotic adjustment in these lines under greenhouse conditions using the re-hydration technique. Using the composite interval mapping technique, we detected 14 QTLs located on chromosomes 1, 2, 3, 4, 5, 7, 8 and 10 that together explained 58% of the phenotypic variability. Most, but not all, of the alleles with positive effects came from the donor parent. On chromosome 8, two QTLs were associated in repulsion. The QTL locations were in good agreement with previous studies on this trait on rice and in other cereals. Some BC₃F₃ lines carried the favorable alleles at the two markers flanking up to four QTLs. Intercrossing these lines followed by marker-aided selection in their progenies will be necessary to recover lines with levels of osmotic adjustment equal to the donor parent. The advanced back-cross strategy appeared to be an appropriate method to accelerate the process of introgressing interesting traits into elite material.Communicated by Q. Zhang