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1.
    
We developed 178 recombinant inbred lines from a southern‐by‐spring oat population designated as “TxH.” These lines were genotyped to generate a high‐quality linkage map that resolved 6,902 markers into 21 linkage groups that matched closely with the latest hexaploid oat consensus map. Three major quantitative trait loci (QTLs) affecting heading date were found in locations that are consistent with known QTLs and candidate genes, and two other QTLs affecting heading date were found in novel locations. Five QTLs affecting plant height were found. Both sets of QTLs are responsible for transgressive segregation observed for these two traits. Four QTLs affecting resistance to crown rust, caused by the pathogen Puccinia coronata f. sp. avenae, were identified. Two of these QTLs are consistent with known clusters of rust resistance genes, while two may represent new locations of novel rust resistance genes. A complete set of SNP sequences suitable for generating markers for molecular selection is provided.  相似文献   

2.
    
Vitamin E (VE) is an important nutritional trait in rice grains. In order to dissect the genetic basis underlying VE content, a recombinant inbred lines population derived from 'Zhenshan 97B' and 'Nanyangzhan' was used for quantitative trait locus (QTL) analysis. Totally, 29 QTLs for six VE traits were identified in 2 consecutive years. Among those, five QTLs repeatedly detected in two years formed a cluster on chromosome 2, which was responsible for all five VE isomers. OsγTMT, the gene encoding γ‐tocopherol methyltransferase in rice, was located to the same region and treated as the candidate gene. Sequence analysis of alleles from two parents revealed many polymorphisms, including 19 single nucleotide polymorphisms (SNPs) and two insert/deletions (Indels) in the promoter region, two nonsynonymous SNPs in exons, and 25 SNPs and an Indel in introns. Besides, a QTL for δ‐tocotrienol and two QTLs for α‐tocopherol were repeatedly detected on chromosome 5 and 8, respectively, all three regions carrying no homologous genes involved in VE biosynthesis. These results could be useful in development of rice lines displaying desirable VE content.  相似文献   

3.
    
The objective of the present study was to analyse the genetic basis of falling number in three winter wheat populations. Samples for falling number determination for each population originated from at least three test environments that were free from the occurrence of preharvest sprouting at harvest time. Quantitative trait locus (QTL) analysis employing falling number values from single environments identified eight, five and three QTL in the populations Dream/Lynx, Bussard/W332‐84 and BAUB469511/Format, respectively. A major QTL common to all three populations and consistently detected in each environment mapped to the long arm of chromosome 7B. The QTL was located to a similar genomic region as the previously described major QTL for high‐isoelectric point α‐amylase content. The T1BL.1RS wheat‐rye translocation and the dwarfing gene Rht‐D1 segregating in Dream/Lynx and BAUB469511/Format were found to be important factors of falling number variation. In both populations, the presence of Rht‐D1b or the absence of T1BL.1RS increased falling number. The results indicate that late maturity α‐amylase, responsible for low falling numbers, has now been documented in German wheat germplasm.  相似文献   

4.
    
The heading date is an important trait for determining regional and climatic adaptability in rice. To expand the adaptability of the indica rice cultivar ‘IR64’, we pyramided multiple early or late heading quantitative trait locus (QTLs) in the ‘IR64’ genetic background by crossing previously developed near-isogenic lines (NILs) with a single QTL for early or late heading. The effects of pyramiding QTLs were observed in three different climatic zones of the Philippines, Madagascar, and Japan. The early heading pyramiding lines (PYLs) headed 6.2 to 12.8 days earlier than ‘IR64’ while the late heading PYLs headed 18.8 to 27.1 days later than ‘IR64’. The PYLs tended to produce low grain yield compared to ‘IR64’. The low yield was not improved by combining SPIKE, which is a QTL that increases the number of spikelets per panicle. Conversely, ‘IR64-PYL(7+10)’ carrying Hd5 and Hd1 headed earlier, produced more tillers, and more panicles per m2 than ‘IR64’, and mitigated the yield decrease in early heading. These results suggest that the effects of pyramided QTLs on heading date were consistent across various environments and PYLs could be used to enhance the adaptation of ‘IR64’ in other rice growing environments.  相似文献   

5.
    
Microsatellite or simple sequence repeat (SSR) markers are important tools for genetic analyses, especially those targeting diversity. The primary objective of this study was to develop robust oat‐based microsatellite markers from newly enriched genomic libraries to expand on a relatively small existing oat SSR toolbox. Microsatellite motifs characterized by (CA/GT), (AAT/TTA), (ATG/TAC) and (CATC/GTAG) repeats were targeted for enrichment. Preliminary screening showed that 90% of clones from the (CA/GT) and 79% of the clones from the (ATG/TAC) libraries contained repeats, while < 11% of the clones from (AAT/TTA) and (CATC/GTAG) libraries contained repeats. Subsequent sequencing of 1536 clones from the (CA/GT) and (ATG/TAC) libraries resulted in 539 and 578 SSRs for which primers were designed, respectively. A total of 246 SSRs were polymorphic across 11 oat lines. One hundred and twenty‐five of the markers produced highly reproducible assays that interrogated 369 alleles at 193 loci. Of these, 79 robust assays interrogated 146 codominant alleles. These markers will be useful for a wide range of genetic analyses in oat including assessment of diversity and marker‐assisted breeding.  相似文献   

6.
    
Waxy barley referred to as low‐amylose or amylose‐free has special advantages in nutrition composition and food processing. Waxy gene encoding granule–bound starch synthase I (GBSSI) is responsible for amylose synthesis in barley. The G3935‐to‐T in Waxy gene has been previously found in amylose–free barley. In this study, G3935‐to‐T was proved to co‐segregate with the waxy phenotype of barley, but has no obvious effect on GBSSI catalytic activity and starch chain length distribution. However, recombinant inbred lines with G3935‐to‐T in Waxy gene are of significant modification in starch granules morphology and pasting properties, increase of grain β‐glucan content, and decrease of thousand kernel weight along with lower kernel width. A polymerase chain reaction with confronting two–pair primers marker was developed for economic and efficient screening of G3935‐to‐T. This study provides the basis for cultivar improvement of waxy barley then fully developing its potential value and utility in food processing.  相似文献   

7.
    
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8.
    
Sugarcane (Saccharum Spp.) produces 80% of the world's sugar along with other by‐products. The production of sugarcane is vulnerable to infestation of sugarcane yellow leaf virus (SCYLV) worldwide. A study was conducted using an F1 segregating population derived from CP95‐1039 × CP88‐1762 to identify the genetic factors underlying SCYLV resistance. The disease infection data were measured using tissue blot immunoassay after 6 years of exposure to the virus under natural field conditions. Genetic maps were created using genotyping by sequencing‐based markers for each parent separately following a pseudo‐testcross approach. Two quantitative trait loci (QTL) were detected for SCYLV resistance accounting for 28% of the phenotypic variation. A major QTL qSCYLR79 located on linkage group 79 and linked with marker 3PAV3154 appears to be unique for SCYLV resistance in sugarcane. Progeny having a combination of two major alleles had 31% less SCYLV incidence than progeny with a combination of major and minor alleles in the genomic region of qSCYLR79. Thus, selection against the minor allele may decrease the SCYLV incidence in sugarcane.  相似文献   

9.
    
Tan spot, caused by a necrotrophic fungus Pyrenophora tritici‐repentis (Ptr), has become an important foliar disease of wheat worldwide. Effective control of tan spot can be achieved by deployment of resistant wheat cultivars. An F2:3 population derived from a cross between synthetic hexaploid wheat (SHW), TA4161‐L1 (moderately resistant) and susceptible winter wheat cultivar, ‘TAM105’ was evaluated with race 1 of Ptr under controlled conditions. The population was genotyped using Diversity Arrays Technology (DArT). Presence of transgressive segregants indicated contribution of positive alleles from both parents. Two major QTLs were located on the short arm of chromosomes 1A and 6A and designated as QTs.ksu‐1A and QTs.ksu‐6A, respectively. Two additional QTLs were identified on chromosome 7A. Resistant alleles of all the QTLs were contributed by TA4161‐L1. Novel QTLs on 6A and 7A can be a valuable addition to known resistance genes and utilized in breeding programmes to produce highly resistant cultivars.  相似文献   

10.
    
Sex expression is of primary importance for the genetic improvement and production of monoecious hemp: masculinized phenotypes are associated with higher fungal sensitivity, and feminized phenotypes with higher seed yields. However, sex expression varies quantitatively among plants and nodes and with time. Here, we developed eight variables that characterize the sex expression in monoecious hemp to dissect its genetic determinism. The monoecy degree (MD), ranging from 1 (mostly male flowers) to 5 (mostly female flowers), was recorded for each node of 167 plants, at 6 times at 1‐week intervals. Two types of longitudinal variables were constructed: ‘synthesis’ (mean MD and percentages of nodes of each MD) and ‘structure’. The latter consisted of the parameters of a logistic curve describing MD as a function of the node position. An r‐square of 0.97 was obtained between the estimated and observed MD values, and the logistic parameters were weakly correlated with each other and with the synthesis variables. Therefore, we conclude that the present modelling approach is relevant for characterizing the sex expression in monoecious hemp.  相似文献   

11.
水稻萌发耐淹性种质资源筛选及QTL定位   总被引:1,自引:0,他引:1  
萌发耐淹性种质资源的筛选、耐低氧萌发基因的挖掘和利用是选育适宜直播水稻新品种的基础。为简便、高效的评价种质资源的萌发耐淹性,本研究对来自不同年代和地区的191份粳稻种质资源进行了萌发耐淹性鉴定,共获得12份萌发耐淹性强的种质资源,其中连粳15号表现出较强的低氧萌发能力。利用其与籼稻品种黄莉占构建的F2:3分离群体,采用模拟大田的鉴定方法,在水稻1号、3号、9号、10号染色体上共检测到4个QTL,即qGS1、qGS3、qGS9和qGS10。共解释表型变异的70.9%,其中qGS1、qGS3和qGS10,能够被重复检测到,贡献率分别为19.2%~24.0%、12.6%~14.7%、19.1%~20.5%,是稳定表达的QTL位点。这些种质资源和QTL的发现为耐低氧发芽水稻新品种的培育提供了重要的亲本资源、基因资源和标记资源,同时也为选育优良直播稻品种提供了理论依据。  相似文献   

12.
    
The objective of this study was to determine quantitative trait loci (QTL) underlying ten floral and related traits in Aquilegia. The traits assessed were calyx diameter, corolla diameter, petal length, petal blade length, sepal length, sepal width, spur length, spur width, plant height and flower number. These are important traits for ornamental value and reproductive isolation of Aquilegia. QTL analysis of these traits was conducted using single‐marker analysis and composite interval mapping (CIM). We used an F2 population consisting of 148 individuals derived from a cross between the Chinese wild species Aquilegia oxysepala and the cultivar Aquilegia flabellata ‘pumila’. Resulting CIM analysis identified 39 QTLs associated with these traits, which were mapped on seven linkage groups. These QTLs could explain 1.22–53.28% of the phenotypic variance. Thirty‐one QTLs, which explained more than 10% of the phenotypic variation, were classified as major QTLs. Graphical representations of the QTLs on seven linkage groups were made. Our research provides the potential for future molecular assisted selection breeding programmes and the cloning of target genes through fine mapping.  相似文献   

13.
    
Ascochyta blight (AB) and botrytis grey mould (BGM) are the most devastating fungal diseases of chickpea worldwide. The wild relative of chickpea, C. reticulatum acc. ILWC 292 was found resistant to BGM whereas, GPF2 (Cicer arietinum L.) is resistant to AB. A total of 187 F8 Recombinant Inbred Lines (RILs) developed from an inter-specific cross of GPF2 × C. reticulatum acc. ILWC 292 were used to identify quantitative trait loci (QTLs) responsible for resistance to AB and BGM. RILs along with parents were evaluated under artificial epiphytotic field/laboratory conditions for two years. Highly significant differences (P < 0.001) were observed for reaction to both pathogens in both years. Parents and RILs were genotyped-by-sequencing to identify genome wide single nucleotide polymorphism (SNPs). A total of 1365 filtered and parental polymorphic SNPs were used for linkage map construction, of which, 673 SNPs were arranged on eight linkage groups. Composite interval mapping revealed three QTLs for AB and four QTLs for BGM resistance. Out of which, two QTLs for AB and three QTLs for BGM were consistent in both years. These QTLs can be targeted for further fine mapping for deployment of resistance to AB and BGM in elite chickpea cultivars using marker-assisted-selection.  相似文献   

14.
    
Cold tolerance is a complex trait, and QTL pyramiding is required for rice breeding. In this study, a total of seven QTLs for cold tolerance in the Japonica rice variety ‘Nipponbare’ were identified in an F2:3 population. A stably inherited major QTL, called qCTS11, was detected in the region adjacent to the centromere of chromosome 11. In a near‐isogenic line population, the QTL was further dissected into two linked loci, qCTS11.1 and qCTS11.2. Both of the homozygous alleles of qCTS11.1 and qCTS11.2 from ‘Nipponbare’ showed major positive effects on cold tolerance. Through pyramiding the linked QTLs in the cold‐sensitive Indica rice cultivar ‘93‐11’, we have developed a new elite, high‐yielding Indica variety with cold tolerance.  相似文献   

15.
    
X. Yin    S. D. Chasalow    P. Stam    M. J. Kropff    C. J. Dourleijn    I. Bos  P. S. Bindraban 《Plant Breeding》2002,121(4):314-319
Genes contributing to the quantitative variation of a complex crop trait can be numerous. However, using existing approaches, the number of quantitative trait loci (QTL) detected for a trait is limited. Therefore, rather than looking for QTL for a complex trait itself, determining QTL for underlying component traits might give more information. In this study the potential of component analysis in QTL mapping of complex traits was examined using grain yield in spring barley as an example. Grain yield was divided into three components: number of spikes/m2, number of kernels/spike, and 1000‐kernel weight. These traits were measured for individuals of a recombinant inbred‐line population in field trials conducted over 2 years. By the use of an approximate multiple QTL model, one to eight QTL were detected for each trait in a year. Some QTL were mapped to similar positions in both years. Almost all QTL for yield were found at the position of or in close proximity to QTL for its component traits. A number of QTL for component traits were not detected when yield itself was subjected to QTL analysis. However, relative to the QTL for yield itself, all component‐trait QTL did not explain the variation in yield better. The results in relation to the potential of using component analysis in studying complex crop traits are discussed.  相似文献   

16.
    
Recombinant inbred lines (RILs) derived from a cross between Brassica rapa L. cv. ‘Sampad’, and an inbred line 3‐0026.027 was used to map the loci controlling silique length and petal colour. The RILs were evaluated under four environments. Variation for silique length in the RILs ranged from normal, such as ‘Sampad’, to short silique, such as 3‐0026.027. Three QTL, SLA3, SLA5 and SLA7, were detected on the linkage groups A3, A5 and A7, respectively. These QTL explained 36.0 to 42.3% total phenotypic variance in the individual environments and collectively 32.5% phenotypic variance. No additive × additive epistatic interaction was detected between the three QTL. Moreover, no QTL × environment interaction was detected in any of the four environments. The number of loci for silique length detected based on QTL mapping agrees well with the results from segregation analysis of the RILs. In case of petal colour, a single locus governing this trait was detected on the linkage group A2.  相似文献   

17.
Recognizing the enormous potential of DNA markers in plant breeding, many agricultural research centers and plant breeding institutes have adopted the capacity for marker development and marker-assisted selection (MAS). However, due to rapid developments in marker technology, statistical methodology for identifying quantitative trait loci (QTLs) and the jargon used by molecular biologists, the utility of DNA markers in plant breeding may not be clearly understood by non-molecular biologists. This review provides an introduction to DNA markers and the concept of polymorphism, linkage analysis and map construction, the principles of QTL analysis and how markers may be applied in breeding programs using MAS. This review has been specifically written for readers who have only a basic knowledge of molecular biology and/or plant genetics. Its format is therefore ideal for conventional plant breeders, physiologists, pathologists, other plant scientists and students.  相似文献   

18.
    
A genetic linkage map of walnut containing 2,220 single nucleotide polymorphisms (SNPs) in 16 linkage groups (LGs) was constructed using an F1 mapping population from a cross between “Chandler” and “Idaho,” two contrasting heterozygous parents. Five quantitative yield traits, lateral fruitfulness, harvest date and three nut traits (shell thickness, nut weight and kernel fill) were then mapped on to linkage groups. A significant quantitative trait locus (QTL) in LG 11 with negative additive effects suggested heterozygote superiority in the expression of lateral bearing. A set of three QTLs explaining ~10% of the variation in harvest date was located in LG 1. Shell thickness, nut weight and kernel fill were under the control of two to three linked pleiotropic QTLs in LG 1 segregating from “Idaho.” The marginal positive additive effects of QTLs for harvest date, shell thickness and nut weight and small negative additive effects for kernel fill suggested that the QTLs had a marginal effect on the expression of these traits.  相似文献   

19.
甘蓝型油菜产量及相关性状的QTL分析   总被引:12,自引:1,他引:11  
高产是甘蓝型油菜育种的重要目标之一,产量是多基因控制的数量性状。本文通过QTL作图分析了产量及其相关性状的数量性状位点,以甘蓝型油菜中油821和保604 F1代小孢子培养获得的DH系为作图群体,构建了由20个连锁群组成的,包括251个分子标记( 2个RFLP标记,72个RAPD标记,91个SSR标记,86个SRAP标记)的遗传连锁图(10个标记没有分配到连锁群中)。图谱的平均图距为6.96 cM,共覆盖油菜基因组1 746.5 cM。在此图谱基础上采取复合区间作图法,检测到与油菜产量及其相关性状有关的QTL共17个。其中控制株高的3个分别位于第4、第9和第10连锁群上,对性状的解释率为9.42%~17.58%;与分枝部位有关的4个分别位于第4、第6和第7连锁群上,其中Bp1 和Bp2 均位于第4连锁群,对性状的解释率为8.13%~15.20%;与主花序有效长有关的3个分别位于第4、第10和第16连锁群上,对性状的解释率为7.49%~23.36%;与一次有效分枝有关的2个分别位于第1、第4连锁群上,对性状的解释率为15.29%~19.58%;与角果总数和千粒重有关的分别位于第4连锁群和第9连锁群上,贡献率分别为17.42%和7.64%;与单株产量有关的3个分别位于第3、第4和第15连锁群,共解释26.60%的表型变异。部分性状的QTL在连锁群上成簇分布,对性状贡献率很大,表现主效QTLs的特点,相应的性状之间也呈显著相关,这表明一因多效或者相关的QTLs之间紧密连锁是性状相关的遗传基础。本研究中与主效QTLs连锁的标记可用于油菜产量性状的分子标记辅助选择。  相似文献   

20.
    
Z. Hao  X. Liu  X. Li    C. Xie    M. Li    D. Zhang    S. Zhang    Y. Xu 《Plant Breeding》2009,128(4):337-341
The maize genome hosts tremendous phenotypic and molecular diversity. Introgression lines (ILs), developed by continuous backcrossing to recurrent parents, could provide a unique genetic stock for quantitative trait locus (QTL) mapping. Using maize lines from six heterotic groups of different ecological zones, we developed >500 BC2F2 IL sets by crossing 11 inbred lines (as recurrent parents) with >200 local maize inbred lines (as donor parents). Of them, 34 IL sets were selected as a subset for drought tolerance screening and a total of 417 ILs survived under severe water stress at seedling stage. One set of 32 surviving ILs, derived from Chang7-2/DHuang212, was used for QTL mapping with simple sequence repeat markers covering the whole genome, with seven QTL detected. Furthermore, investigating all surviving ILs, we identified two common regions in bin 3.04, corresponding to marker intervals bnlg1904–umc1772 and umc1223–bnlg1957, respectively, which shared high genetic variation in three IL sets. Our results indicated that selective genotyping can be used to identify genetic loci for complex traits. The ILs, highly selected for drought tolerance in this study, provide a unique set of materials for both genomic studies and development of enhanced germplasm resources.  相似文献   

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