首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
Plant breeding programs aim to develop cultivars with high adaptability to the specific conditions in a local region. As a result, unique genes and gene combinations have been accumulated in local elite breeding populations during the long history of plant breeding. Genetic analyses on such genes and combinations may be useful for developing new cultivars with more-desirable agronomic traits. Here, we attempted to detect quantitative trait loci (QTL) for rice blast resistance (BR) using a local breeding rice population from Hokkaido, Japan. Using genotyping data on single nucleotide polymorphisms and simple sequence repeat markers distributed throughout the whole genomic region, we detected genetic regions associated with phenotypic variation in BR by a genome-wide association mapping study (GWAS). An additional association analysis using other breeding cultivars verified the effect and inheritance of the associated region. Furthermore, the existence of a gene for BR in the associated region was confirmed by QTL mapping. The results from these studies enabled us to estimate potential of the Hokkaido rice population as a gene pool for improving BR. The results of this study could be useful for developing novel cultivars with vigorous BR in rice breeding programs.  相似文献   

2.
Understanding genetic diversity among local populations is a primary goal of modern crop breeding programs. Here, we demonstrated the genetic relationships of rice varieties in Hokkaido, Japan, one of the northern limits of rice cultivation around the world. Furthermore, artificial selection during rice breeding programs has been characterized using genome sequences. We utilized 8,565 single nucleotide polymorphisms and insertion/deletion markers distributed across the genome in genotype-by-sequencing for genetic diversity analyses. Phylogenetics, genetic population structure, and principal component analysis showed that a total of 110 varieties were classified into four distinct clusters according to different populations geographically and historically. Furthermore, the genome sequences of 19 rice varieties along with historic representations in Hokkaido, nucleotide diversity and FST values in each cluster revealed that artificial selection of elite phenotypes focused on chromosomal regions. These results clearly demonstrated the history of the selections on agronomic traits as genome sequences among current rice varieties from Hokkaido.  相似文献   

3.
越冬栽培稻是一类能越过自然冷冬季节并在第2年春季萌芽、正常开花结实、收获稻谷的水稻品种。本文通过对越冬栽培稻产量性状QTL分析,明确产量相关性状的遗传规律,旨在进一步解析越冬栽培稻产量性状的遗传机制,为育种创新利用提供理论依据。以3份越冬栽培稻构建的3个半同胞F2群体为材料。各考察15个产量相关性状,利用Excel 2003、GraphPad Prism 5.0和QTL IciMapping 4.10软件分析数据、绘制遗传图谱、定位QTL和联合分析。结果表明,产量性状表型值在3群体中呈连续正态分布,表现为数量性状遗传。共检测到37个QTL和26对上位性QTL,贡献率分别介于2.32%~36.31%和1.04%~2.05%;检测到9个同时影响2个及以上产量性状(一因多效)QTL标记区间;以联合分析检测到13个产量性状相关QTL,其中4个QTL区间与单群体检测QTL区间重叠;越冬栽培稻产量相关性状QTL以加–显性效应遗传为主、上位性遗传效应为辅。本研究将为越冬栽培稻产量相关基因挖掘及育种创新利用奠定基础。  相似文献   

4.
Anther and stigma size are critical floral traits that influence outcrossing in rice (Oryza sativa), a crop that is predominantly self-fertilizing. The efficiency of hybrid rice seed production depends on efficient outcrossing ability of parental lines, which is promoted by increased anther and stigma size. Phenotypic correlations between anther and stigma traits have been observed in many studies; however, evidence for this relationship is unclear and the genetic basis remains to be elucidated. To examine this relationship and to identify quantitative trait loci (QTLs) for increased anther and stigma size, we developed two advanced backcross QTL mapping populations derived from a cross between a Thai elite indica crop variety (SPR1) and an accession of common wild rice (O. rufipogon Griff.), which is predominantly outcrossing. One mapping population was selected for increased anther size while the other was selected for increased stigma size. We mapped QTLs for anther size and stigma size in both populations. Bulked segregant analysis was used to identify molecular markers associated with the selected traits. A total of 16 significant QTLs associated with anther and stigma traits were identified across the two populations, and these were located in five genomic regions on four chromosomes. Whereas three of these regions have been previously reported, two of them are newly identified and should be further explored for improving outcrossing ability in rice. The co-localization of QTL for anther and stigma traits strongly suggests some degree of shared developmental basis for these traits.  相似文献   

5.
选用204对SSR标记对全国野生大豆群体(174份代表性样本)的基因组扫描,采用TASSEL软件的GLM (general linear model)方法对百粒重、开花期、成熟期、干豆腐得率、干豆乳得率和耐淹性性状值关联分析,解析与性状关联位点的优异等位变异,鉴别出一批与农艺、加工性状关联的优异等位变异及携带优异等位变异的载体材料;进一步分析极值表型材料的遗传构成。结果表明: (1)累计51个位点(次)与性状关联,有些标记同时与2个或多个性状相关联,可能是性状相关的遗传基础;关联位点中累计16位点(次)与连锁分析定位的QTL一致;(2)与地方品种群体和育成品种群体的关联位点比较,发现野生群体关联位点只有少数与之相同,群体间育种性状的遗传结构有明显差异。(3)与多性状关联的位点其等位变异对不同性状的效应方向可相同可不同,如GMES5532a-A332对百粒重和耐淹性的相对死苗率都是增效效应,而GMES5532a-A344对百粒重是减效效应,对相对死苗率是增效效应;(4)极值表型材料间的遗传构成有很大差异。表型值大的材料携带较多增效效应大的位点等位变异,例如N23349的百粒重是9.08 g,含有4个增效效应较大的位点等位变异;表型值小的材料携带较多减效效应大的位点等位变异,如N23387的百粒重是0.75 g,含有4个减效效应较大的位点等位变异。关联作图得到的信息可以弥补连锁定位信息的不足,尤其是全基因组位点上复等位变异的信息为育种提供了亲本选配和后代等位条带辅助选择的依据。  相似文献   

6.
To improve salt tolerance of two elite rice varieties, Ce258 and Zhongguangxiang1 (ZGX1), two sets of introgression lines (ILs) each comprising 200 BC1F10 lines derived from a common donor, IR75862, and two recipient parents, Ce258 and ZGX1, were used for mapping of QTLs for four salt tolerance‐related traits at the seedling stage. Although the three parents were susceptible to salt, the two IL populations showed transgressive segregations for salt tolerance with 12 and 8 salt tolerance ILs in the Ce258‐ILs and ZGX1‐ILs. Eighteen main‐effect QTLs were identified for the four traits in the two IL populations, and the IR75862 alleles at most loci showed increased and decreased salt tolerance in the ZGX1 and Ce258 backgrounds, suggesting overwhelming genetic background effects on QTL detection for salt tolerance. The qDSS11 simultaneously detected in the two backgrounds was validated in a F2 population derived from a salt tolerance line and ZGX1. Our results indicated that salt tolerance‐enhancing allele could be identified in the elite susceptible breeding lines and that introgression of the favourable alleles could facilitate the development of superior lines with greater salt tolerance levels.  相似文献   

7.
To identify quantitative trait loci (QTLs) associated with the primary target traits for selection in practical rice breeding programs, backcross inbred lines (BILs) derived from crosses between temperate japonica rice cultivars Nipponbare and Koshihikari were evaluated for 50 agronomic traits at six experimental fields located throughout Japan. Thirty-three of the 50 traits were significantly correlated with heading date. Using a linkage map including 647 single-nucleotide polymorphisms (SNPs), a total of 122 QTLs for 38 traits were mapped on all rice chromosomes except chromosomes 5 and 9. Fifty-eight of the 122 QTLs were detected near the heading date QTLs Hd16 and Hd17 and the remaining 64 QTLs were found in other chromosome regions. QTL analysis of 51 BILs having homozygous for the Koshihikari chromosome segments around Hd16 and Hd17 allowed us to detect 40 QTLs associated with 27 traits; 23 of these QTLs had not been detected in the original analysis. Among the 97 QTLs for the 30 traits measured in multiple environments, the genotype-by-environment interaction was significant for 44 QTLs and not significant for 53 QTLs. These results led us to propose a new selection strategy to improve agronomic performance in temperate japonica rice cultivars.  相似文献   

8.
Cold tolerance at booting stage is one of the major determinants for a stable yield of rice (Oryza sativa L.) in many high elevation or high latitude regions. Understanding the genetic basis of cold tolerance is crucial for the improvement of cold tolerance through breeding. In this study, association mapping was performed in 347 rice accessions worldwide with different statistical models in order to identify the genetic marker loci/QTL associated with cold tolerance traits at the booting stage. The evaluation of cold tolerance for all the traits was conducted under natural low temperature in Yunnan and cold water irrigation in Jilin. The 148 SSRs were used for the genotyping. Population structure analysis identified three main subpopulations for the accessions that corresponded to major geographic origins. The relative kinship analysis revealed a weak or no relationship for most of the individual pairs. Model comparisons indicated that the Q+K model controlling both population structure (Q) and the relative kinship (K) was performed better than other models in association mapping. In total, 24 markers were identified that were significantly associated with cold tolerance, including five markers in Yunnan and 19 markers in Jilin. Moreover, RM282, RM252, RM335 and RM6824 were identified in multiple environments or years. Many of these identified markers were located either in or nearby the regions where the QTLs have been reported for cold tolerance at booting stage. These results highlighted the targeted regions for future studies and might be subsequently used in breeding programs to trace and select the useful alleles by MAS.  相似文献   

9.
Breeding of excellent rice varieties is essential for modern rice production. Typical breeding procedures to introduce and maintain valuable agricultural traits require at least 8 generations from crossing to stabilization, always taking more than 4–5 years of work. This long and tedious process is the rate-limiting step in the development of new varieties, and therefore fast culturing methods are in urgent need. Taking advantage of early flowering characteristics of light-sensitive rice under short-day conditions, we have developed a practical protocol to accelerate the breeding cycle of rice, which we have termed the “1 + 2”, “2 + 2”, “1 + 3”, and “0 + 5” methods according to the different rice varieties and different breeding purposes. We have also incorporated several techniques, including glume cutting, seed desiccation at 50°C in a drier seed dormancy breakage with low concentration of HNO3, and direct seeding. Using the above strategy, we have shortened the life cycle of light-sensitive rice varieties to about 70 days, making it possible for several rice cultivars to proliferate 4–5 generations in a single calendar year. This protocol greatly accelerates the process of new variety breeding, and can be used in rice research for shortening the process of genetic analysis and the construction of mapping populations.  相似文献   

10.
Drought is an important constraint to productivity in rainfed rice environments. Improvement in the various components of rice drought tolerance is now possible through the identification and manipulation of DNA markers linked with genes controlling these quantitative traits. A recombinant inbred line population was derived from the cross IAC165 × Co39. A molecular map was built that contained 182 RFLP and microsatellite markers. Segregation distortions were limited to a few chromosomal segments. Constitutive root traits, including maximum root length, root thickness and root dry weight in various layers, were measured on 125 lines in a greenhouse replicated experiment. QTL analysis was performed using composite interval mapping. Between 1and 4 main effect QTLs, which explained individually between 5.5 and 24.8% of the variability, were identified for each trait. The most important genomic regions, which carried QTLs for several traits, were found on chromosomes 1, 4, 9, 11 and 12.The QTL locations were in good agreement with previous studies on these traits, confirming the value of the QTLs in a different genetic background. Epistasis represented a non-negligible component of the observed variability for some of the traits but was not detected for others. These results add to the understanding of the genetic control of root morphology in rice, which is necessary to strengthen marker-aided selection programs to improve varieties for water-limited environments. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

11.
Vigorous cold tolerance at the fertilization stage (CTF) is a very important characteristic for stable rice production in cold temperature conditions. Because CTF is a quantitatively inherited trait, pyramiding quantitative trait loci (QTLs) using marker-assisted selection (MAS) is effective for improving CTF levels in rice breeding programs. We previously identified three QTLs controlling CTF, qCTF7, qCTF8 and qCTF12, using backcrossed inbred lines derived from a cross between rice cultivar Eikei88223 (vigorous CTF) and Suisei (very weak CTF). However, pyramiding of these QTLs for the application of MAS in practical rice breeding programs have not yet been elucidated. In this study, we examined the effect of pyramiding QTLs for improvement of CTF level using eight possible genotype classes from the 152 F3 population derived from a cross between Eikei88223 and Suisei. Increasing of CTF levels in combinations between qCTF7 and qCTF12 and between qCTF8 and qCTF12 were detected. Furthermore, we compared the haplotype pattern around the QTLs for CTF among the rice cultivars from Hokkaido. These results are useful for improvement of new cultivars with high CTF levels using MAS and identification of genetic resources with the novel QTL(s) for CTF.  相似文献   

12.
Cold temperature during the reproductive phase leads to seed sterility, which reduces yield and decreases the grain quality of rice. The fertilization stage, ranging from pollen maturation to the completion of fertilization, is sensitive to unsuitable temperature. Improving cold tolerance at the fertilization stage (CTF) is an important objective of rice breeding program in cold temperature areas. In this study, we characterized fertilization behavior under cold temperature to define the phenotype of CTF and identified quantitative trait loci (QTLs) for CTF. A wide variation in CTF levels has been identified among local cultivars in Hokkaido, which is one of the most northern regions for rice cultivation in the world. Clear varietal differences in pollen germination, and pollen tube elongation due to cold temperature have been observed. These differences may confer a degree of CTF among this population. We conducted QTL analysis for CTF using 120 backcrossed inbred lines derived from a cross between Eikei88223 (vigorous CTF) and Suisei (very weak CTF). Three QTLs for CTF were identified. A clear effect by QTL, qCTF7, for increasing the level of CTF was validated using advanced progeny. These results will facilitate marker-assist selection for desirable QTLs for CTF in rice breeding program.  相似文献   

13.
利用品质性状的回交选择导入系挖掘水稻抗纹枯病QTL   总被引:5,自引:1,他引:4  
将优质、抗纹枯病的高秆供体Tarom Molaii和Binam导入半矮秆IR64和特青背景,培育品质性状回交选择构建的4个导入系群体IR64/Tarom Molaii、特青/Tarom Molaii、IR64/Binam和特青/Binam,定位了影响水稻抗纹枯病病级(disease scale, DS)、相对病斑高度(relative lesion height, RH)和株高(plant height, PH)的QTL。结果表明,4个导入系群体的DS与RH高度相关,两者与PH呈显著负相关。导入系后代各性状均呈现超亲分离,出现抗性明显优于双亲的抗病个体,其中40%左右属半矮秆抗病类型。采用单向方差分析,在这4个群体中分别定位到10、8、8和6个影响3个性状的QTL,多数基因座上降低DS和RH即增强抗病性同时增加株高的等位基因均来自两个供体。未在同一供体两个不同背景下检测到影响3个性状的相同QTL,表明抗纹枯病QTL表达有明显的遗传背景效应。PH与DS及PH与RH被定位在同一个显著标记位点的QTL数分别占两个性状QTL总数的38%和52%,表明水稻纹枯病抗性与株高关系密切,两者存在许多连锁位点。与以往相同群体品质性状QTL的定位结果相比,发现品质性状QTL与抗纹枯病QTL大多分布在染色体的不同区域,彼此独立遗传。对利用目标性状选择导入系定位非目标性状QTL的效果、影响因素及育种应用进行了探讨,强调了目标性状选择导入系对非目标性状QTL发掘及育种应用的重要性。  相似文献   

14.
Improving the eating quality of cooked rice has been one of the most important objectives in rice breeding programs. Eating quality of cooked rice is a complex trait including several components, such as external appearance, taste, aroma, and texture. Therefore, dissection of these components followed by marker-assisted selection of detected QTL(s) may be a useful approach for achieving desirable eating quality in rice breeding. Whiteness of cooked rice (WCR) is an important factor related to the external appearance of cooked rice. WCR is known to be associated with the amylose and protein contents of the endosperm. However, the genetic basis of WCR remains unclear. In this study, we evaluated phenotypic variation in WCR among recently developed rice cultivars from Hokkaido, Japan. Then, we developed doubled haploid lines (DHLs) derived from a cross between two cultivars from Hokkaido, Joiku No. 462 (high WCR) and Jokei06214 (low WCR). Using the DHLs, we detected two QTLs for WCR, qWCR3 and qWCR11, on chromosomes 3 and 11, respectively. We also examined the dosage effect of the two QTLs based on both the categorized segregants in the DHLs and the relationship between the WCR phenotype and inheritance around the QTL regions in cultivars from Hokkaido.  相似文献   

15.
Grain shape is an important trait for improving rice yield. A number of quantitative trait loci (QTLs) for this trait have been identified by using primary F2 mapping populations and recombinant inbred lines, in which QTLs with a small effect are harder to detect than they would be in advanced generations. In this study, we developed two advanced mapping populations (chromosome segment substitution lines [CSSLs] and BC4F2 lines consisting of more than 2000 individuals) in the genetic backgrounds of two improved cultivars: a japonica cultivar (Koshihikari) with short, round grains, and an indica cultivar (IR64) with long, slender grains. We compared the ability of these materials to reveal QTLs for grain shape with that of an F2 population. Only 8 QTLs for grain length or grain width were detected in the F2 population, versus 47 in the CSSL population and 65 in the BC4F2 population. These results strongly suggest that advanced mapping populations can reveal QTLs for agronomic traits under complicated genetic control, and that DNA markers linked with the QTLs are useful for choosing superior allelic combinations to enhance grain shape in the Koshihikari and IR64 genetic backgrounds.  相似文献   

16.
The demand for superior grain quality represents a major issue in rice (Oryza sativa L.) breeding. To study the genetic basis of rice grain quality, including traits specifying grain dimension and percentage of grains with chalkiness, quantitative genetic analysis was conducted in a population of 37 introgression lines (ILs) of indica elite variety Habataki in the background of japonica cultivar Sasanishiki across two different environments. The ILs showed transgressive segregation for all of the investigated traits, including percentage of grains with chalkiness, brown grain length, width, thickness, length/width ratio, length/thickness ratio, volume and 1,000-brown grain weight, the result indicated that these rice grain quality traits were polygenic phenomenon. Fifty-four QTLs were identified on eleven chromosomes, and 44 QTLs were associated with more than one trait, as a cause of the observed phenotypic correlations between different traits. Five stable QTLs, namely QPGWC.NH-1.1, QPGWC.NH-1.2, QGW.NH-3.1, QLW.NH-7.1 and QGV.NH-8.2, were identified in this study. This study provides useful information for marker-aided improvement of grain quality (grain dimension and percentage of grains with chalkiness) in rice; moreover, ILs carrying these QTLs constitute good candidates for future fine mapping and positional cloning projects.  相似文献   

17.
Rice is one of the most important crops in the world. The wild species of rice are expected to have novel beneficial alleles that have been lost from cultivated rice during the process of domestication. Therefore, wild species could be the potential source to induce lost genetic diversity in cultivated rice. Serving as an important reservoir of novel genes/QTLs, wild species, in general, are better adapted to different ecologies and can tolerate many biotic and abiotic stresses. Despite that, only a few wild species are studied and extensive characterization both at the molecular and morphological level is yet to be achieved. Several agronomically important genes/QTLs for improving biotic and abiotic stresses, resistance, productivity and grain quality traits were identified from AA genome donor wild species and were tagged with breeder friendly molecular markers for their transfer to elite genetic backgrounds. The present review provides information on the important wild rice species harbouring genes/QTLs for agriculturally important traits and their successful utilization in rice breeding programmes.  相似文献   

18.
孙慧敏  张军  赵团结  盖钧镒 《作物学报》2010,3(10):1615-1623
利用自然群体进行关联分析是检测目标性状QTL、揭示其遗传基础的有效方法。对国内黄淮和南方地区和东亚、东南亚、南亚291份大豆品种幼苗期耐淹性和64个SSR标记的关联分析结果表明,整个群体由国内和国外2个不同的亚群体组成,2个亚群均存在连锁不平衡。在群体1(国内)中分别检测到相对死苗率、相对失绿率、相对萎蔫率的关联位点3、7和12个,群体2(国外)中相应位点6、3和5个;多个位点兼与2个或者3个耐淹性状关联;部分关联位点与连锁定位结果一致。在2个群体中分别筛选出3个耐淹性状减效最大(最耐淹)的优异等位变异24个和22个。相对死苗率优异等位变异在黄淮、南方地区5个主要系谱中分布不同,育种轮次间有波动。结合基因型和耐性表现,从国内材料中优选出合豆2号、黔豆3号、诱变31、南农493-1,从国外材料中优选出PI208432、PI377576、PI481690等耐淹载体材料,为耐淹育种奠定材料和标记辅助选择育种的基础。  相似文献   

19.
Guo  Longbiao  Zhu  Lihuang  Xu  Yunbi  Zeng  Dali  Wu  Ping  Qian  Qian 《Euphytica》2004,140(3):155-162
Effective cumulative temperature (ECT) after heading would be a more reasonable parameter for seed sampling of pre-harvest sprouting/seed dormancy (SD) tests in segregating populations than the days after flowering. SD is an important agronomic trait associated with grain yielding, eating quality and seed quality. To identify genomic regions affecting SD at different grain-filling temperatures, and to further examine the association between SD and ECT during grain-filling, 127 double haploid (DH) lines derived from a cross between ZYQ8 (indica)/JX17 (japonica) by anther culture were analyzed. The quantitative trait loci (QTLs) and their digenic epistasis for SD were identified using a molecular linkage map of this population. A total of four putative QTLs for SD (qSD-3, qSD-5, 6 and 11) were detected on chromosomes 3, 5, 6 and 11, together explaining 41.4% of the phenotypic variation. Nine pairs of digenic epistatic loci were associated with SD on all but chromosome 9, and their contributions to phenotypic variation varied from 2.87%–8.73%. The SD QTL on chromosome 3 was identical to the QTLs found in other mapping populations with different genetic backgrounds, which could be a desirable candidate for gene cloning and marker-assisted selection in rice breeding.  相似文献   

20.
Two genetic linkage maps based on doubled haploid (DH) and recombinant inbred lines (RILs) populations, derived from the same indica-japonica cross ‘Samgang × Nagdong’, were constructed to analyze the quantitative trait loci (QTLs) affecting agronomic traits in rice. The segregations of agronomic traits in RILs population showed larger variations than those in DH population. A total of 10 and 12 QTLs were identified on six chromosomes using DH population and seven chromosomes using RILs population, respectively. Three stable QTLs including pl9.1, ph1.1, and gwp11.1 were detected through different years. The percentages of phenotypic variation explained by individual QTLs ranged from 8 to 18% in the DH population and 9 to 33% in the RILs population. Twenty-three epistatic QTLs were identified in the DH population, while 21 epistatic QTLs were detected in the RILs population. Epistatic interactions played an important role in controlling the agronomic traits genetically. Four significant main-effect QTLs were involved in the digenic interactions. Significant interactions between QTLs and environments (QE) were identified in two populations. The QTLs affecting grain weight per panicle (GWP) were more sensitive to the environmental changes. The comparison and QTLs analysis between two populations across different years should help rice breeders to comprehend the genetic mechanisms of quantitative traits and improve breeding programs in marker-assisted selection (MAS).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号