野生稻高产QTL的分子标记辅助育种进展

1995年中国国家杂交水稻工程技术研究中心与美国康奈尔大学合作,在马来西亚普通野生稻中鉴定出两个主效高产QTLyld1.1和yld2.1.随后将野生稻高产QTL导入优良晚稻恢复系测64-7及中稻恢复系9311和明恢63中,采用分子标记辅助选择与田间选择相结合,育成了Q611等携带野生稻高产QTL yld1.1和yld2.1的新恢复系.经测交鉴定,Q611所配组合表现出强大的产量优势,说明野生稻高产QTL具有显著的增产效应和重要的育种价值,同时也表明采用分子标记辅助选择方法对数量性状进行遗传改良同样具有明显的效果.     

利用野生稻高产基因培育超级杂交稻研究

传统育种方法在挖掘和利用水稻栽培品种的遗传资源方面日趋饱和,进一步提高杂交水稻产量潜力必须考虑利用水稻野生近缘种的有利基因库。随着分子生物学技术的发展,越来越多的研究揭示出作物的野生近缘种中蕴藏着许多有利基因。分子标记辅助选择在定向导入这些远缘有利基因方面显示出许多优越性,日益成为活跃的作物科学研究领域之一。介绍了马来西亚普通野生稻的2个高产QTLs的发现及其分子标记辅助选择在培育超级杂交稻方面的初步进展,并展望了这一领域的研究前景。     

分子标记在水稻育种中的应用

分子标记技术的应用日趋广泛,对水稻育种研究有重要的价值。通过重点介绍近年来分子标记在水稻分子遗传图谱的构建、遗传资源保存和遗传多样性分析、基因的标记及克隆、分子标记辅助育种等方面研究的应用情况,探讨了分子标记的应用在水稻育种上的优势。     

野生稻增产QTL导入9311之近等基因系的构建

以超级杂交中稻恢复系9311为受体和轮回亲本,马来西亚普通野生稻(O.rufipogon)为增产QTL yld1.1和yld2.1的供体进行杂交和连续回交,各世代采用分子标记辅助选择,至BC6F1后自交,得到BC6F2群体,通过分子标记检测,获得分别携带野生稻增产QTL yld1.1、yld2.1及同时携带yld1.1和yld2.1的3套近等基因系.对同时携带yld1.1和yld2.1的近等基因系进行遗传背景分析,发现其与受体9311的遗传组成有93.9%一致.田间试验表明,野生稻增产QTL近等基因系的产量均高于受体,说明将野生稻增产QTL转移至杂交稻恢复系中,能提高其产量水平,且2个QTL的增产效果大于单个QTL的效果.     

马来西亚普通野生稻增产QTL的分子标记辅助选择及其育种效果

位于马来西亚普通野生稻（Oryza rufipogon）第1和第2染色体上的两个主效增产QTL（yld1.1和yld2.1）分别具有18%和17%的增产效果。为探明野生稻增产QTL对杂交水稻产量性状改良的效果,以超级杂交稻亲本9311为受体和轮回亲本,马来西亚普通野生稻为增产QTL供体进行杂交和连续回交,并利用与这两个增产QTL紧密连锁的4个SSR分子标记对回交群体进行分子鉴定和辅助选择。产量比较试验结果显示, 育成的携带野生稻增产QTL的9311改良系比受体9311增产,主要表现为有效穗数和每穗总粒数显著增加;携带野生稻增产QTL的稳定株系所配杂交组合也比对照显著增产。研究表明野生稻增产QTL yld1.1和QTL yld2.1导入栽培水稻品种的遗传背景后能显著提高产量潜力,可作为超级杂交稻育种重要资源。     

SSR分子标记在稻瘟病抗性育种中的应用

稻瘟病俗称水稻癌症,每年都造成严重损失。实践证明,发展抗性育种是解决这一问题最有效的方法之一。SSR分子标记为辅助选育抗稻瘟病水稻新品种和抗性鉴定提供了新的方法和手段。阐述了SSR分子标记在水稻遗传连锁图谱构建、稻瘟病抗性基因定位、稻瘟病菌危害研究、分子标记辅助育种当中的应用,以为以后的研究奠定基础。     

SSR标记技术在水稻遗传育种中的应用

SSR是建立在PCR基础上的分子标记,与RFLP、RAPD、AFLP相比,SSR具有多态性高、结果稳定可靠、重复性好、操作简单等特点,已在水稻研究中被广泛应用。阐述了SSR标记的基本原理与操作规程,介绍了其在构建水稻连锁图谱、水稻品种特异性鉴定及水稻分子标记辅助育种等方面的应用情况。并分析了目前SSR在应用中所存在的问题,提出相应的解决方法,以期推动SSR标记技术在遗传育种研究中的进展,从而加速育种进程。     

茶树分子标记辅助育种研究进展

茶树是多年生异花授粉作物,育种效率低.分子标记辅助选择技术可以显著提高育种效率,已成为作物遗传育种领域的研究重点.发掘与目标性状紧密连锁的功能性分子标记是开展分子标记辅助选择育种的前提,目前主要依靠QTL作图与关联作图两种方法.简述了QTL作图和关联作图在茶树分子标记辅助育种研究中的进展及存在的问题,并对其发展趋势进行了展望.     

大豆QTL定位的研究进展

QTL定位就是以分子标记技术为工具、以遗传连锁图谱为基础、利用分子标记与QTL之间的连锁关系确定控制数量性状的基因在基因组中的位置.本文综述了大豆农艺性状、生理性状、抗虫性状等的QTL定位及分子标记辅助育种的研究进展.     

水稻抗稻瘟病遗传育种研究进展

稻瘟病是我国水稻生产中最严重的病害之一。简述了稻瘟病的危害、发病过程和抗性遗传机理,综述了稻瘟病抗性基因定位和克隆、分子标记辅助育种相关研究进展,探讨了水稻抗稻瘟病育种及其研究方向。     

Use of Major Quantitative Trait Loci to Improve Grain Yield of Rice

Further improvement of rice productivity remains a challenge. Breeding is perceived as an important option to increase rice yield. However, the genetic progress of grain yield in most rice breeding programs was slow in the last decades. Although great progress in rice genomics and molecular biology has been achieved, the effect of such technological innovations on rice breeding is far small. Marker-assisted selection （MAS） for a few target quantitative trait loci （QTLs） has significant effects in improving qualitative traits, such as disease resistance. The success of MAS has therefore motivated breeders to identify and use major QTLs for yield and yield component traits. In this review, we summarized the recent methods in QTL identification, including novel statistical methods for linkage and association mapping, special population types, and whole-genome sequencing. We reviewed the successful application of marker-assisted gene introgression and gene pyramiding to improve grain yield and discussed the design of efficient MAS schemes to further increase the success rate of breeding programs. The use of well-characterized major QTLs through introgression and gene pyramiding is proven effective in improving grain yield, particularly yield under abiotic stress. Major QTLs that are stable across genetic background and growing environments are often found in less adapted germplasms, such as landraces and wild relatives. Advanced backcross QTL analysis and introgression lines, which integrate QTL discovery and utilization, are important methods for exploiting major QTLs contained in such germplasms. Next-generation sequencing substantially increases mapping resolution and accelerates the identification of casual genes underlying major QTLs. Practical guidelines derived from theoretical and empirical studies are given to guide the design of efficient marker-assisted gene introgression and pyramiding schemes.     

野生稻种质资源在水稻育种中的利用

针对目前中国水稻育种面临的遗传资源利用范围狭窄这一主要问题，从重要基因资源的发掘角度，综述了野生稻种质资源的利用现状，探讨了其在水稻超高产育种、抗病虫育种、抗逆性育种、品质育种等方面的应用潜力。     

QTL Analysis for Yield Traits Related to Low Nitrogen Tolerance Using Backcrossing Recombinant Inbred Lines Derived from Dongxiang Wild Rice (Oryza rufipogon Griff.)

【Objective】Dongxiang wild rice (Oryza rufipogon Griff.) has strong low nitrogen tolerance and is an important germplasm for low nitrogen tolerance improvement. Identification of genes responsible for low nitrogen tolerance in Dongxiang wild rice is of great importance to understand molecular mechanisms of low nitrogen tolerance and develop rice varieties with low nitrogen tolerance. 【Method】Quantitative trait loci (QTLs) for plant height and yield traits under low and normal nitrogen conditions was identified using backcrossing recombinant inbred lines (BC1F12) derived from an interspecific cross Xieqingzao B // Dongxiang wild rice/Xieqingzao B and its genetic linkage. 【Result】A total of 57 QTLs were detected in 33 regions on all chromosome, except chromosome 4 and 8. They explained individually 3.17%~63.40% phenotypic variation, and 32 QTLs of them had favorable alleles derived from Dongxiang wild rice. Nineteen QTLs were simultaneously detected under both nitrogen treatments, and 38 QTLs were only identified under single nitrogen treatment, suggesting various genetic mechanisms in rice growth and yield formation under low and normal nitrogen conditions. 【Conclusion】Fourteen QTL clusters, 43 QTLs included, scattered on seven chromosomes, indicating the common genetic-physiological mechanisms behind different traits, and the QTL pyramiding for low nitrogen tolerance can be achieved by molecular marker-assisted selection.     

提高水稻杂种优势水平的可能途径

杂交水稻的单产处于徘徊状态。提高单产的可靠途径在于扩大双亲的遗传差异, 进一步提高杂种优势水平。培育“杂交水稻超高产群体理想型”, 应用分子标记辅助相互轮回选择法累加不同组群的优势基因和应用分子标记技术挖掘与利用野生稻中的远缘优势基因, 有可能大幅度地提高杂交水稻的单产潜力。     

Quantitative Trait Locus Mapping of High Photosynthetic Efficiency and Biomass in Oryza longistaminata

Photosynthetic efficiency, a key trait that determines yield potential in rice, is quantitatively regulated by multiple genes. Utilization of valuable genetic resources hidden in wild rice is an effective way to improve rice photosynthesis and yield potential. In this study, 152 backcross inbred lines derived from wild rice Oryza longistaminata were explored for QTL mapping of photosynthetic rate (Pn) and biomass (BM) in natural fields. Five novel QTLs for Pn and seven QTLs for BM or daily biomass (DBM) derived from O. longistaminata were identified. One of these QTLs, qPn8.1, could significantly improve Pn and was located in a 68-kb region containing only 11 candidate genes. Meanwhile, qBM1.1 and qDBM1.1 for BM and DBM on chromosome 1 were overlapped with qPn1.1 for Pn from 9311, and could affect both Pn and BM in natural fields. These QTLs identified in O. longistaminata may provide a novel alternative to explore new genes and resources for yield potentiality, highlighting the important role of wild rice in rice breeding programs.     

Dissecting Genetic Basis of Deep Rooting in Dongxiang Wild Rice

Deep rooting is an important trait in rice drought resistance. Genetic resources of deep-rooting varieties are valuable in breeding of water-saving and drought-resistant rice. In the present study, 234 BC₂F₇ backcross introgression lines were derived from a cross of Dongye 80 (an accession of Dongxiang wild rice as the donor parent) and R974 (an indica restorer line as the recurrent parent). A genetic linkage map containing 1 977 bin markers was constructed by ddRADSeq for QTL analysis. Thirty-one QTLs for four root traits (the number of deep roots, the number of shallow roots, the total number of deep roots and the ratio of deep roots) were assessed on six rice chromosomes in two environments (2020 Shanghai and 2021 Hainan). Two of the QTLs, qDR5.1 and qTR5.2, were located on chromosome 5 in a 70-kb interval. They were detected in both environments. qDR5.1 explained 13.35% of the phenotypic variance in 2020 Shanghai and 12.01% of the phenotypic variance in 2021 Hainan. qTR5.2 accounted for 10.88% and 10.93% of the phenotypic variance, respectively. One QTL (qRDR2.2) for the ratio of deep roots was detected on chromosome 2 in a 210-kb interval and accounted for 6.72% of the phenotypic variance in 2020. The positive effects of these three QTLs were all from Dongxiang wild rice. Furthermore, nine and four putative candidate genes were identified in qRDR2.2 and qDR5.1/qTR5.2, respectively. These findings added to our knowledge of the genetic control of root traits in rice. In addition, this study will facilitate the future isolation of candidate genes of the deep-rooting trait and the utilization of Dongxiang wild rice in the improvement of rice drought resistance.     

应用东乡野生稻回交重组自交系分析水稻耐低氮产量相关性状QTL

目的 东乡野生稻低氮耐性强,是水稻耐低氮育种的重要资源。鉴定东乡野生稻耐低氮基因对研究耐低氮遗传机制、培育耐低氮水稻品种具有重要意义。方法 利用协青早B//东乡野生稻/协BBC₁F₁₂回交重组自交系及其遗传图谱,应用Windows QTL Cartographer 2.5分析施氮肥和不施氮肥下的株高和产量相关性状QTL。结果 共检测到57个控制株高和产量性状的QTL,分布于10条染色体上的33个区域,单个QTL表型贡献率为3.17%~63.40%,其中32个QTL的增效等位基因来自东乡野生稻。19个QTL在施氮和未施氮条件下均检测到,38个QTL仅在单一环境下检测到显著效应,表明不同施氮水平下水稻性状的遗传机制不同。结论 43个QTL分别聚集于7条染色体上的14个QTL簇,表明不同性状涉及到共同遗传机制,并可通过分子标记辅助选择方法进行耐低氮有利等位基因的聚合育种。     

野生稻优良基因资源的研究与应用进展

野生稻是栽培稻的野生近缘种,作为重要的基因资源,具有诸多的优良性状,如野生稻对病虫害的抗性、对各种逆境的耐受性以及胞质雄性不育等,已被广泛应用于现代栽培稻的育种改良,成为栽培稻遗传改良的丰富基因源和不可替代的物质基础。本文综述了野生稻优良基因的发掘和种质资源的利用现状,总结了野生稻保护和利用目前存在的问题,并对其在水稻育种中的应用潜力做出了展望。     

水稻粒型基因克隆和调控机制研究进展

水稻粒型是影响其产量和品质的重要性状,阐明其遗传调控机理,有助于提高水稻单产和改良品质。水稻粒型性状主要包括粒长、粒宽、粒厚、长/宽比,属于数量性状,受胚、胚乳及母体植株等不同遗传体系的控制。随着水稻功能基因组学和重测序技术的快速发展,目前已经定位超过400个与水稻粒型相关的数量性状位点(QTL),并已克隆了60个水稻粒型基因,涉及植物激素、泛素-蛋白酶体通路、丝裂原活化蛋白激酶(MAPK)信号通路、G蛋白信号通路及表观修饰等多个调控通路。本文对水稻粒型基因克隆及其调控机制的研究进展进行了系统总结和梳理,并对这些基因在育种上的利用价值进行了评价。     

非AA型野生稻资源在水稻育种中的利用

非AA型野生稻涵盖B、C、D、E、F、G、H、J、K等九大基因组,广泛分布于世界各地,具有丰富的遗传多样性,是一座天然的水稻基因宝库。综述了非AA型野生稻的种类、优良特性及其在水稻育种中的利用途径和育种成果,指出了目前利用非AA型野生稻存在的主要问题,提出了相应的策略。