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1.

Background

Harvest index (HI) in rice is defined as the ratio of grain yield (GY) to biomass (BM). Although it has been demonstrated that HI is significantly related to yield and is considered as one of the most important traits in high-yielding rice breeding, HI-based high-yielding rice breeding is difficult due to its polygenic nature and insufficient knowledge on the genetic basis of HI. Therefore, searching for rice varieties with high HI and mapping genes associated with high HI can facilitate marker-assisted breeding for high HI in rice.

Results

Yuexiangzhan, a popular indica cultivar with good reputation of high HI was crossed with Shengbasimiao, an indica cultivar with lower HI to develop a recombinant inbred line population, and QTL mapping for HI and its component traits was conducted. In total, five QTLs for HI, three QTLs for GY, and six QTLs for BM were detected in two-year experiments. Among the three GY QTLs, one co-located with the HI QTL on chromosome 8, while the other two co-located with the two tightly-linked BM QTLs on chromosome 3. The co-located QTLs in each of the chromosomal regions produced additive effects in the same direction. Particularly, the HI QTL on chromosome 8, qHI-8, could be detected across two years and explained 42.8% and 44.5% of the phenotypic variation, respectively. The existence of qHI-8 was confirmed by the evaluation of the near isogenic lines derived from a residual heterozygous line, and this QTL was delimitated to a 1070 kb interval by substitution mapping.

Conclusion

In the present study, the detected GY QTLs overlapped with both HI QTL and BM QTL, suggesting a positive relationship between GY and HI or BM, respectively. With an understanding of the genetic basis for grain yield, harvest index and biomass, it is possible to achieve higher yield through enhancing HI and BM by pyramiding the favorable alleles for the two traits via marker-assisted selection (MAS). As qHI-8 has a large phenotypic effect on HI and expresses stably in different environments, it provides a promising target for further genetic characterization of HI and MAS of high HI in rice breeding.
  相似文献   

2.
【目的】创制优质香型丝苗米水稻新种质，探索水稻育种改良新途径，助力广东丝苗米品牌建设。【方法】以广东省农业主导品种粤农丝苗(YNSM)与优质稻粤王丝苗(YWSM)为材料，利用CRISPR/Cas9基因编辑技术定点编辑上述品种的香味基因Badh2，创制香稻新品系，随后通过分子标记辅助选择(MAS)技术定向导入GW7/GL7位点，系谱选育优质香型丝苗米水稻新种质。【结果】利用CRISPR/Cas9基因编辑技术成功创制两个香稻新品系yn-kobadh2与yw-kobadh2，其2-AP含量均极显著提高，达到239.39～440.79μg/kg，而有效穗数、每穗实粒数、糙米外观品质、千粒重与产量等主要农艺性状均未受到显著影响；MAS技术结合系谱选育的方法成功选育两个丰产性好、籽粒长宽比超过4.3的优质香型丝苗米水稻新品系NWbadh2GW7-1与NWbadh2GW7-2，达到广东丝苗米品种关于香味与外观粒型的认定标准。【结论】利用CRISPR/Cas9基因编辑与分子辅助选择技术相结合可精准、高效地创制新的优...  相似文献   

3.
Varalu is an early maturing rice variety widely grown in the rainfed ecosystem preferred for its grain type and cooking quality. However, the yield of Varalu is substantially low since it is being affected by reproductive drought stress along with the blast disease. The genetic improvement of Varalu was done by introgressing a major yield QTL, qDTY12.1, along with two major blast resistance genes i.e. Pi54 and Pi1 through marker-assisted backcross breeding. Both traits were transferred till BC2 generation and intercrossing was followed to pyramid the two traits. Stringent foreground selection was carried out using linked markers as well as peak markers (RM28099, RM28130, RM511 and RM28163) for the targeted QTL (qDTY12.1), RM206 for Pi54 and RM224 for Pi1. Extensive background selection was done using genome-wide SSR markers. Six best lines (MSM-36, MSM-49, MSM-53, MSM-57, MSM-60 and MSM-63) having qDTY12.1 and two blast resistance genes in homozygous condition with recurrent parent genome of 95.0%-96.5% having minimal linkage drag of about 0.1 to 0.7 Mb were identified. These lines showed yield advantage under drought stress as well as irrigated conditions. MSM-36 showed better performance in the national coordinated trials conducted across India, which indicated that improved lines of Varalu expected to replace Varalu and may have an important role in sustaining rice production. The present study demonstrated the successful marker-assisted pyramiding strategy for introgression of genes/QTLs conferring biotic stress resistance and yield under abiotic stress in rice.  相似文献   

4.
野生稻高产QTL的分子标记辅助育种进展   总被引：16，自引：3，他引：16  
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.  相似文献   

5.
【Objective】The objective of the study is to identify new genes related to heading date and yield related traits in rice, and to screen the elite rice lines carrying favorable alleles, therefore providing new genes and excellent germplasm for molecular marker-assisted (MAS) breeding.【Method】The multi-parent generation inter-crosses (MAGIC) population MAGIC-Hei was planted in 2017 and 2018 in Changsha, Hunan Province. Genome-wide association analysis was performed to detect the quantitative trait loci associated with heading date, number of tillers per plant, grain number per panicle, seed setting rate, 1000-grain weight and grain yield per plant based on genotyping by sequencing (GBS).【Results】Totally, 26 QTLs that control heading date and yield related traits were identified on all the chromosomes except chromosome 10 in the two years. Of these, 11 are new and qNTP9, associated with the number of effective panicles, was detected in the two years. qNTP9 was less affected by environment and could be used for further fine mapping and gene cloning. Based on the phenotypic and the SNP genotypes five elite lines carrying favorable alleles were selected, which could be used for future high-yielding rice breeding. 【Conclusion】The loci associated with heading date and yield related traits could be used for rice breeding.  相似文献   

6.
关于超级稻品种培育的资源和基因利用问题   总被引：11，自引：1，他引：11  
 超级稻育种是矮化育种和杂种优势利用的深化,其本质是资源或基因及基因与环境互作的综合利用。为给超级稻育种提供思路,回顾和分析了超级稻育种中的资源及基因综合利用现状,包括籼粳基因渐渗及利用、栽培稻产量QTL累加及利用、野生稻产量及抗病基因发掘及利用、株型和根系相关基因的发掘及遗传改良等。指出由于真正能用于超级稻育种的有利基因及连锁标记还不多,水稻基因研究成果还不足以支撑超级稻分子育种,目前的超级稻育种仍以常规杂交技术和资源的综合利用为主。需要进一步发掘高产、优质、抗病虫、抗逆基因,常规育种技术与分子育种技术相结合,培育广适性或绿色超级稻。  相似文献   

7.
野生稻高产基因及其分子标记辅助育种研究   总被引：27，自引：8，他引：27  
传统遗传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,分子标记辅助选择在定向导入远缘有利基因方面的研究日益活跃.介绍了马来西亚普通野生稻的2个高产QTLs(即yld1.1和yld2.1)的发现及其分子标记辅助育种的进展,并展望了这一领域的研究前景.  相似文献   

8.
土壤盐渍化严重制约水稻生产发展,提高耐盐性已成为水稻育种的重要目标之一。挖掘水稻耐盐新基因,解析其分子作用机制可以为水稻耐盐性遗传改良奠定基础。本文从定位群体、耐盐性鉴定时期和鉴定方法、耐盐性评价指标、鉴定到的耐盐QTL、耐盐QTL的精细定位和图位克隆等方面,总结了近年来水稻耐盐QTL定位研究中所取得的进展;介绍了水稻耐盐/盐敏感突变体筛选和基因克隆以及耐盐性关联分析的研究近况;并对水稻耐盐性分子标记辅助选择改良的现状作了概述。  相似文献   

9.
《Plant Production Science》2013,16(3):334-337
Abstract

Pearl millet [Pennisetum glaucum (L.) R. Br.] is the staple cereal of the hottest, driest areas of the tropics and subtropics. Drought stress is a regular occurrence in these regions, making stress tolerance an essential attribute of new pearl millet cultivars. Recent breeding research has mapped several quantitative trait loci (QTLs) for components of grain and stover yield per se, as well as yield maintenance, under terminal drought stress conditions. We report here the evaluation of these QTLs as possible selection criteria for improving stress tolerance of an elite hybrid cultivar. Initial evaluations, based on hybrids made with topcross pollinators bred from lines selected directly from the mapping population, indicated an advantage to the QTL-based topcross hybrids. This advantage seemed to be related to a particular plant phenotype that was similar to that of the drought tolerant parent of the mapping population. Subsequent evaluations were based on testcross hybrids of drought tolerance QTL introgression lines in the background of the drought-sensitive parent of the mapping population, H 77/833-2. These introgression lines were bred by limited marker-assisted backcrossing of a putative major drought tolerance QTL into H 77/833-2 from the mapping population’s drought tolerant parent. Several of these QTL introgression lines had a significant positive general combining ability for grain yield under terminal stress and significantly out-yielded testcross hybrids made with the original recurrent parent both in unrelieved terminal drought stress and in gradient stress evaluations.  相似文献   

10.
野生稻增产QTL导入9311之近等基因系的构建   总被引：4，自引：2，他引：4  
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.  相似文献   

11.
回交导入系是利用回交及标记辅助选择的手段构建而成的遗传与育种材料。经过多代回交，后代材料在轮回亲本的遗传背景下只包含一个或少量供体亲本染色体片段，因此，可作为QTL分析的重要材料。同时，多代回交有利于打破优异基因与不良基因的连锁，优异基因导入到整体表现优良的轮回亲本材料中，进而实现对育种材料的改良。鉴于其一致的遗传背景，导入系在QTL精细定位和基因克隆、QTL间互作研究、遗传验证及作物聚合育种和分子设计育种中均发挥重要的作用。本文对回交导入系的构建及其在作物遗传育种中的应用进行综述。  相似文献   

12.
基于小麦产量三要素的产量条件QTL分析   总被引：2，自引：0，他引：2  
为了从单个QTL水平上解析产量与产量三要素的遗传基础,利用花培3号和豫麦57杂交获得的168个家系的DH群体及其遗传图谱,在5个环境下对产量进行了非条件QTL分析和基于产量三要素(穗粒数、千粒重和单位面积穗数)的条件QTL分析,共检测到9个非条件QTL和28个条件QTL。其中,检测到2个主效QTL(QY.sdau-4D和QY.sdau-6D.2),它们可分别解释15.77%和10.16%的表型变异。分别检测到6个"一因多效"QTL和11个微效QTL;其中,QYsdau-4D.2通过影响单位面积穗数、穗粒数和千粒重而影响产量,QYsdau-2D.1和QYsdau-3A.1能提高单位面积产量但不影响穗粒数,即单位面积产量和穗粒数在该位点上几乎没有关联。本研究结果为通过分子设计聚合高产有利基因提供了理论基础,对培育单位面积产量大幅度提高的小麦新品种具有重要意义。  相似文献   

13.
【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.  相似文献   

14.
不同年份水稻产量性状的QTL分析   总被引：7，自引：1，他引：6  
分别于2005年和2006年利用热研2号（粳稻）和密阳23（籼稻）为亲本构建的含111个家系的F6和F7重组自交系群体,对单株穗数、每穗颖花数、每穗实粒数、结实率、千粒重和单株产量6个性状进行了QTL分析。两年共检测到分布于7条染色体上的19个QTL,其中2005年检测到10个,2006年检测到14个,两年相同的QTL 5个。大多数性状之间具有显著的表型相关性,相关性较强的性状之间具有较多共同或紧密连锁的QTL。检测到3个控制产量性状的QTL区域存在一因多效或紧密连锁,其中第8染色体上RM5556-RM331区域两年同时检测到控制每穗颖花数、每穗实粒数以及单株产量的QTL。这些QTL为通过分子标记辅助选择提高水稻产量提供了有用信息。  相似文献   

15.
A marker-assisted back-cross (MABC) programme was used to introgress four root quantitative trait loci (QTLs) from the tropical japonica rice variety Azucena into the Indian upland rice variety, Kalinga III. Previously we tested the products for root traits and reported that the introgressed QTL9 (on chromosome 9) significantly increased root length in the new genetic background. Here we describe field testing for agronomic traits in near-isogenic lines (NILs) that differ for introgressed QTLs. Four NILs were selected and characterised in replicated field experiments in eastern and western India over 3 years. They were tested by upland farmers in a target population of environments (TPE) in three states of eastern India, over 2 years. NILs out-performed Kalinga III for grain and straw yield and there was interaction between the genotypes and the environment (G × E). No effect was found for the root QTL9 on grain or straw yield, however, the presence of several introgressions significantly improved both traits. Some of this effect was due to introgression of Azucena alleles at non-target regions. Overall, the Azucena introgressions increased straw yield more than grain yield. While it has yet to be demonstrated whether this effect is due to improved root systems, this finding fits with the assumption that introgressed genes are involved in partitioning of biomass to the roots and stems, rather than to the grain. The NILs could replace Kalinga III for cultivation in medium upland environments in eastern India.  相似文献   

16.
The quantitative resistance gene pi21 from Sensho was introgressed to an indica breeding line IR63307-4B-13-2, a pyramiding line IRBB4/5/13/21, and a tropical japonica line Kinandang Patong by marker-assisted backcrossing. A total of 192 improved lines at the BC_4F_3 and BC_4F_4 generations were developed and confirmed to have the gene introgression via genotyping using a pi21-specific In Del marker. Thirteen randomly selected improved lines, representing all the three genetic backgrounds, demonstrated resistance against leaf blast composites in the field and a broader spectrum resistance against individual isolates compared to the recurrent parents in the glasshouse. Specifically, the tested lines exhibited pi21-acquired resistance against 11 leaf blast isolates that elicited susceptible reactions from the recurrent parents. All the tested lines maintained a comparative heading date, and similar or improved panicle length, number of primary branches per panicle and number of total grains per panicle relative to the recurrent parents. The physical grain characteristics of the recurrent parents were also maintained in the 13 lines tested, although variability in the amylose content and chalkiness degree was observed. The successful marker-assisted introgression of pi21 in diverse genetic backgrounds and the resulting broader spectrum resistance of improved lines against leaf blast indicate the potential of pi21 for deployment in cultivars grown across other rice growing regions in Asia.  相似文献   

17.
水稻粒重及其相关性状的遗传解析   总被引：47，自引：3，他引：47  
 应用292个 Lemont/ 特青F13重组自交系(RILs)和272个标记的遗传连锁图谱分析粒重及籽粒长、宽、厚、长/宽、体积和容重6个相关性状的遗传。所有性状在RILs中出现超亲分离。粒重与其他籽粒性状均呈显著正相关，而涉及籽粒品质的容重与粒宽、粒厚呈显著负相关。检测到影响粒重及其相关性状的主效QTL 48个和互作位点38对，这些QTL解释了各性状55%以上的表型变异。80%以上的主效QTL呈现一因多效或生理相关。QGl3和 QGl2等通过籽粒体积间接影响粒重， Lemont增效等位基因有利于籽粒品质的改良，而QGw5、QGt1和QGv7的特青增效等位基因增加粒重同时降低籽粒容重及品质。通过标记辅助选择进行不同QTL的重组，有望在增加粒重的同时改善籽粒品质。  相似文献   

18.
Genetic improvement is one of the most effective strategies to prevent rice from blast and bacterial blight(BB) diseases,the two most prevalent diseases jeopardizing rice production.Rice hybrids with dural resistance to blast and BB are needed for sustainable production of food.An incomplete diallele design resulted in 25 crosses between five blast and five BB resistant germplasm accessions.Only one pair of parents,DH146 × TM487,showed polymorphism for all the markers to identify one blast resistance gene Pi25 and three BB resistance genes,Xa21,xa13 and xa5,thus it was used in the marker-assisted selection(MAS).F2 individuals of DH146 × TM487 were genotyped using flanking markers of RM3330 and sequence tagged site(STS) marker SA7 for Pi25.The resistant F2 plants with Pi25 were used for pyramiding BB resistance genes Xa21,xa13 and xa5 identified by the markers pTA248,RM264 and RM153,respectively in subsequent generations.Finally,after selection for agronomic traits and restoration ability among 12 pyramided lines,we acquired an elite restorer line,R8012 including all four target genes(Pi25+Xa21+xa13+xa5).Hybrid Zhong 9A/R8012 derived from the selected line showed stronger resistance to blast and BB,and higher grain yield than the commercial checks uniformally in experimental plots,2007 state-wide yield trial and 2008 nation-wide yield trial.This study provides a paradigmatic example to show that MAS is a practically feasible tool in effectively pyramiding multiple resistance genes.The resultant restoring line and its hybrid would play an important role in securing rice production in China.  相似文献   

19.
Molecular design breeding is one of straightforward approaches to break yield barriers in rice. In this study, GW6 gene for grain length and width from Baodali was transferred into an indica recurrent parent 9311 and a japonica variety Zhonghua 11 （ZH11） using marker-assisted backcross （MAB）. One and three introgression lines were selected for phenotypic analysis from 9311 and ZH11 genetic backgrounds, respectively. SSL-1, an improved 9311 near isogenic line with GW6 performed 11%, 19% and 6.7%higher of grain length, 1000-grain weight and single plant yield, respectively, as compared with 9311. All the three improved ZH11-GW6 lines, R1, R2 and R3, had more than 30% increase in grain weight and about 7%higher in grain yield. Seed plumpness of R1, R2 and R3 was improved synchronously because the three ZH11-GW6 lines contained GIF1 （Grain Incomplete Filling 1）, a dominant grain filling gene. Thus, GW6 has high potential in increasing the yield of inbred lines through MAB, making it an important genetic resource in super hybrid rice breeding. This study provides insights in the utilization of GW6 for large grain and high yield rice breeding via molecular design breeding.  相似文献   

20.
【目的】本研究旨在挖掘水稻粒型新基因、探索其分子机理,解析籽粒发育调控遗传网络奠定基础,并为通过分子标记聚合有利基因开展超级稻分子设计育种提供理论依据。【方法】以植株和籽粒形态差异较大的晚粳稻品种春江16B(CJ16B）和广亲和中籼稻背景恢复系C84为亲本构建含有188个家系的重组自交系为作图群体,利用158对在双亲中存在多态性差异的分子标记,构建了遗传连锁图谱,总遗传距离为1428.40cM,平均标记间距为9.04cM。在构建遗传图谱的基础上,完成RIL188个株系籽粒的粒长、粒宽、粒厚、长宽比和千粒重等5个性状考查并进行QTL定位。【结果】在海南陵水和浙江杭州两地共检测到籽粒相关主效QTL30个,包括籽粒QTL新座位18个,解释遗传变异3.51%~17.25%。其中粒长、粒宽、粒厚和长宽比QTL位点分别为9个、5个、5个和6个,千粒重QTL位点5个。经基因座位比对,发现有5个QTL区间与已克隆的调控籽粒形态相关基因座位相近,我们通过对双亲目标基因的测序并根据差异位点设计dCAPs分子标记进行验证。【结论】该RIL群体及其遗传图谱可用于水稻重要农艺性状主效QTL基因的定位和克隆,新定位的18个粒型QTL可以为水稻籽粒发育调控网络提供补充和资料积累。  相似文献   

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