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1.
Wild soybean, the progenitor of cultivated soybean, is an important gene pool for ongoing soybean breeding efforts. To identify yield-enhancing quantitative trait locus (QTL) or gene from wild soybean, 113 wild soybeans accessions were phenotyped for five yield-related traits and genotyped with 85 simple sequence repeat (SSR) markers to conduct association mapping. A total of 892 alleles were detected for the 85 SSR markers, with an average 10.49 alleles; the corresponding PIC values ranged from 0.07 to 0.92, with an average 0.73. The genetic diversity of each SSR marker ranged from 0.07 to 0.93, with an average 0.75. A total of 18 SSR markers were identified for the five traits. Two SSR markers, sct_010 and satt316, which are associated with the yield per plant were stably expressed over two years at two experimental locations. Our results suggested that association mapping can be an effective approach for identifying QTL from wild soybean.  相似文献   

2.
To fully exploit the diversity in African rice germplasm and to broaden the gene pool reliable information on the population genetic diversity and phenotypic characteristics is a prerequisite. In this paper, the population structure and genetic diversity of 42 cultivated African rice (Oryza spp.) accessions originating from West Africa (Benin, Mali and Nigeria, Liberia etc.) were investigated using 20 simple sequence repeats (SSR) and 77 amplified fragment length polymorphisms (AFLP). Additionally, field trials were set up to gain insight into phenotypic characteristics that differentiate the genetic populations among rice accessions. The analysis revealed considerably high polymorphisms for SSR markers (PIC mean?=?0.78) in the germplasm studied. A significant association was found between AFLP markers and geographic origin of rice accessions (R?=?0.72). Germplasm structure showed that Oryza sativa accessions were not totally isolated from Oryza glaberrima accessions. The results allowed identification of five O. glaberrima accessions which grouped together with O. sativa accessions, sharing common alleles of 18 loci out of the 20 SSR markers analyzed. Population structure analysis revealed existence of a gene flow between O. sativa and O. glaberrima rice accessions which can be used to combine several interesting traits in breeding programs. Further studies are needed to clarify the contributions of this gene flow to valuable traits such as abiotic and biotic stresses including disease resistance.  相似文献   

3.
小豆遗传差异、群体结构和连锁不平衡水平的SSR分析   总被引：1，自引：0，他引：1  
利用57对小豆SSR标记和31对绿豆SSR标记,用5份日本材料作对照,对249份中国小豆种质进行遗传差异、群体结构和连锁不平衡(LD)分析。结果表明,共检测到630个等位变异,SSR位点等位变异数在2~17之间,遗传多样性指数范围为0.024~0.898,平均为0.574。15个不同地理来源群体间表现出显著的遗传多样性差异,其中中国云南最高,河北、天津最低。聚类分析将254份材料划分为3个类群,在一定程度上和地理生态环境相关。LD分析显示和其他作物相比,小豆LD衰减距离较短,最大衰减距离为5.8 cM (R2>0.1),基因组LD平均衰减距离小于1 cM (R2>0.1,P<0.001)。  相似文献   

4.
Quantitative trait loci (QTLs) with additive (a), additive × additive (aa) epistatic effects, and their treatmental interactions (at and aat) were studied under salt stress and normal conditions at seedling stage of wheat (Triticum aestivum L.). A set of 182 recombinant inbred lines (RILs) derived from cross Xiaoyan 54 × Jing 411 were used. A total of 29 additive QTLs and 17 epistasis were detected for 12 traits examined, among which eight and seven, respectively, were identified to have QTL × treatment effects. Physiological traits rather than biomass traits were more likely to be involved in QTL × treatment interactions. Ten intervals on chromosomes 1A, 1D, 2A (two), 2D, 3B, 4B, 5A, 5B and 7D showed overlapping QTLs for different traits; some of them represent a single locus affecting different traits and/or the same trait under both treatments. Eleven pairs of QTLs were detected on seemingly homoeologous positions of six chromosome groups of wheat, showing synteny among the A, B and D genomes. Ten pairs were detected in which each pair was contributed by the same parent, indicating a strong genetic plasticity of the QTLs. The results are helpful for understanding the genetic basis of salt tolerance in wheat and provide useful information for genetic improvement of salt tolerance in wheat by marker-assisted selection.  相似文献   

5.
Bermudagrass is a warm season grass widely cultivated for turf and fodder. Nonetheless, the grass has poor forage quality because animals that consume it fail to assimilate its organic matter efficiently. Thus, identification of the marker-trait association between simple sequence repeat (SSR) markers and forage-quality-related traits in diverse bermudagrass accessions would enable efficient selection of high forage quality bermudagrass cultivars. Association mapping of 8 forage-related-quality traits with 1474 markers was conducted in 60 diverse bermudagrass accessions from five geographical regions in China. Significant variations in eight phenotypic and physiological traits were observed among the 60 accessions. A total of 1474 alleles were amplified by 104 SSR primers. The average gene diversity and polymorphic information content for the study sample were 0.2097 and 0.1748 respectively. The clustering analysis suggested that geographic origin influenced genetic distances between accessions. A total of 76 markers significantly associated with traits at P < 0.01; 73 with a single trait and 3 with two traits each. Nevertheless, only 41 significant marker-trait associations (MTAs) were observed after Bonferroni test was separately conducted for each trait. Forty-one microsatellites had significant associations with 8 forage-quality-related traits. These markers provide a feasible means of genetically improving forage quality in bermudagrass after further authentication.  相似文献   

6.
A quantitative trait loci (QTL) analysis of grain yield and yield-related traits was performed on 93 durum wheat recombinant inbred lines derived from the cross UC1113 × Kofa. The mapping population and parental lines were analyzed considering 19 traits assessed in different Argentine environments, namely grain yield, heading date, flowering time, plant height, biomass per plant, and spikelet number per ear, among others. A total of 224 QTL with logarithm of odds ratio (LOD) ≥ 3 and 47 additional QTL with LOD > 2.0 were detected. These QTL were clustered in 35 regions with overlapping QTL, and 12 genomic regions were associated with only one phenotypic trait. The regions with the highest number of multi-trait and stable QTL were 3BS.1, 3BS.2, 2BS.1, 1BL.1, 3AL.1, 1AS, and 4AL.3. The effects of epistatic QTL and QTL × environment interactions were also analyzed. QTL putatively located at major gene loci (Rht, Vrn, Eps, and Ppd) as well as additional major/minor QTL involved in the complex genetic basis of yield-related traits expressed in Argentine environments were identified. Interestingly, the 3AL.1 region was found to increase yield without altering grain quality or crop phenology.  相似文献   

7.
Genome-wide association studies (GWAS) are useful to facilitate crop improvement via enhanced knowledge of marker-trait associations (MTA). A GWAS for grain yield (GY), yield components, and agronomic traits was conducted using a diverse panel of 239 soft red winter wheat (Triticum aestivum) genotypes evaluated across two growing seasons and eight site-years. Analysis of variance showed significant environment, genotype, and genotype-by-environment effects for GY and yield components. Narrow sense heritability of GY (h 2  = 0.48) was moderate compared to other traits including plant height (h 2  = 0.81) and kernel weight (h 2  = 0.77). There were 112 significant MTA (p < 0.0005) detected for eight measured traits using compressed mixed linear models and 5715 single nucleotide polymorphism markers. MTA for GY and agronomic traits coincided with previously reported QTL for winter and spring wheat. Highly significant MTA for GY showed an overall negative allelic effect for the minor allele, indicating selection against these alleles by breeders. Markers associated with multiple traits observed on chromosomes 1A, 2D, 3B, and 4B with positive minor effects serve as potential targets for marker assisted breeding to select for improvement of GY and related traits. Following marker validation, these multi-trait loci have the potential to be utilized for MAS to improve GY and adaptation of soft red winter wheat.  相似文献   

8.
Association mapping relies on the variation and extent of linkage disequilibrium within a species to identify genes of interest; this is an alternative to linkage mapping in traditional biparental population, which exploits only the variation in the two parents of the mapping population. This study was designed to identify association between 48 SSR markers and downy mildew (DM) resistance using a set of 60 public and private maize inbred lines in Thailand. Genetic diversity and population structure in the set were calculated. A total of 489 alleles with an average gene diversity of 0.70 revealed two subpopulations among the 60 maize inbred lines. Analysis of variance resulted in significant effects of phenotypic values of tested entries, with significant effects of inbred lines, locations, and their interaction. In addition, the analysis of variance for broad sense heritability also indicated high heritability (0.97), and association analysis revealed three significant SSR-trait associations (P < 0.05). These three significant SSR loci have not been reported in previous linkage mapping studies. Our results suggest that new allelic variants associated with DM resistance in these germplasm collections should be useful to help identify new lines carrying alleles for DM resistance in breeding marker-assisted selection programs.  相似文献   

9.
Enhanced root growth in plants is fundamental to improve soil water exploration and drought tolerance. Understanding of the variance components and heritability of root biomass allocation is key to design suitable breeding strategies and to enhance the response to selection. This study aimed to determine variance components and heritability of biomass allocation and related traits in 99 genotypes of wheat (Triticum aestivum L.) and one triticale (X. Triticosecale Wittmack) under drought-stressed and non-stressed conditions in the field and greenhouse using a 10?×?10 alpha lattice design. Days to heading (DTH), days to maturity (DTM), number of tillers (NPT), plant height (PH), spike length (SL), shoot and root biomass (SB, RB), root to shoot ratio (RS), thousand kernel weight (TKW) and yield (GY) were recorded. Analyses of variance, variance components, heritability and genetic correlations were computed. Significant (p?<?0.05) genetic and environmental variation were observed for all the traits except for spike length. Drought stress decreased heritability of RS from 47 to 28% and GY from 55 to 17%. The correlations between RS with PH, NPT, SL, SB and GY were weaker under drought-stress (r?≤???0.50; p?<?0.05) compared to non-stressed conditions, suggesting that lower root biomass allocation under drought stress compromises wheat productivity. The negative association between GY and RS (r?=???0.41 and ??0.33; p?<?0.05), low heritability (<?42%) and high environmental variance (>?70%) for RS observed in this population constitute several bottlenecks for improving yield and root mass simultaneously. However, indirect selection for DTH, PH, RB, and TKW, could help optimize RS and simultaneously improve drought tolerance and yield under drought-stressed conditions.  相似文献   

10.
To better understand the genetic diversity of the cultivated Upland cotton (Gossypium hirsutum L.) and its structure at the molecular level, 193 Upland cotton cultivars collected from 26 countries were genotyped using 448 microsatellite markers. These markers were selected based on their mapping positions in the high density G. hirsutum TM-1 × G. barbadense 3-79 map, and they covered the whole genome. In addition, the physical locations of these markers were also partially identified based on the reference sequence of the diploid G. raimondii (D5) genome. The marker orders in the genetic map were largely in agreement with their orders in the physical map. These markers revealed 1,590 alleles belonging to 732 loci. Analysis of unique marker allele numbers indicated that the modern US Upland cotton had been losing its genetic diversity during the past century. Linkage disequilibrium (LD) between marker pairs was clearly un-even among chromosomes, and among regions within a chromosome. The average size of a LD block was 6.75 cM at r 2 = 0.10. A neighbor-joining phylogenic tree of these cultivars was generated using marker allele frequencies based on Nei’s genetic distance. The cultivars were grouped into 15 groups according to the phylogenic tree. Grouping results were largely congruent with the breeding history and pedigrees of the cultivars with a few exceptions.  相似文献   

11.
N. Watanabe 《Euphytica》2017,213(8):201
Einkorn wheat, Triticum monococcum L. (2n = 2x = 14, AmAm genome), is a primitive, cultivated form of diploid wheat. The shortcoming of einkorn is that it lacks the free-threshing habit. Early heading and semi-dwarf traits are also required to fit modern agricultural practice. In the present study we developed T. monococcum pre-breeding germplasm having early, free threshing traits by utilizing an early heading source, two sources of soft glume (spike) and three sources of semi-dwarfism to combine their phenotypes into pre-breeding materials. We found two different genes determined free threshing of einkorn wheat. One of them was the sog (soft glume) gene from Triticum sinskajae Filat. et Kurkiev (2n = 2x = 14, AmAm genome) and another was the sos (soft spike) gene, which was completely linked or pleiotropic with the gene for semi-dwarfism. The genes sos, spd (short peduncle) and sd17654 (semi-dwarf CItr 17654) were utilized to develop semi-dwarf T. monococcum lines. Field performance of 6 early and free-threshing pre-breeding materials with sos and spd genes were tested over three crop seasons. Five semi-dwarf pre-breeding materials (PBMs) were obtained. However, these materials had slightly less grain yield than #252 (tall and hulled check) and PBM-1 (tall free-threshing check). Harvest index of the pre-breeding materials was improved due to the presence of sos and spd genes. If optimized cultivation practice is performed, these pre-breeding materials can be utilized as sources of early, free-threshing and semi-dwarf traits to produce modern T. monococcum varieties.  相似文献   

12.
In wheat, strong genetic correlations have been found between grain yield (GY) and tiller number per plant (TN), fertile spikelet number per spike (FSN), kernel number per spike (KN) and thousand‐kernel weight (TKW). To investigate their genetic relationships at the individual quantitative trait locus (QTL) level, we performed both normal and multivariate conditional QTL analysis based on two recombinant inbred lines (RILs) populations. A total of 79 and 48 normal QTLs were identified in the International Triticeae Mapping Initiative (ITMI)/SHW‐L1 × Chuanmai 32 (SC) populations, respectively, as well as 55 and 35 conditional QTLs. Thirty‐two QTL clusters in the ITMI population and 18 QTL clusters in the SC population explained 0.9%–46.2% of phenotypic variance for two to eight traits. A comparison between the normal and conditional QTL mapping analyses indicated that FSN made the smallest contribution to GY among the four GY components that were considered at the QTL level. The effects of TN, KN and TKW on GY were stronger at the QTL level.  相似文献   

13.
Over recent years, quality has become an important commercial issue for durum wheat breeders. Modern breeding methods are most efficient for producing and supplying the best quality raw materials to the pasta industry. Here we assessed the effectiveness of molecular marker-assisted selection of quality traits in durum wheat. To this end, DNA and quality trait markers were jointly used to analyze quality-related traits in a durum wheat collection. A total of 132 durum wheat (Triticum turgidum ssp. durum) Mediterranean landraces, international lines, and Moroccan cultivars were analyzed for seven important qualityrelated traits including thousand-kernel weight (TKW), test weight (TW), gluten strength, yellow pigment (YP), and grain protein content (GPC). Additionally, 18 simple sequence repeat (SSR) markers previously reported to be associated with different quality traits were analyzed. Of these, 14 (78%) were polymorphic and four were monomorphic. There were between two and seven alleles per locus, with an average of four alleles per locus. The average phenotypic variation value (R2) ranged from 2.81 to 20.43%. Association analysis identified nine markers significantly associated with TKW, TW, and YP, followed by eight markers associated with GPC, six markers associated with yellow index b, four markers associated with brightness L, and three markers associated with SDS-sedimentation volume. This study highlights the efficiency of SSR technology, which holds promise for a wide range of applications in marker-assisted wheat breeding programs.  相似文献   

14.
普通小麦D染色体组微卫星分子标记遗传差异研究   总被引：13，自引：1，他引：12  
本研究采用微卫星(SSR)分子标记技术, 对我国不同生态区的6个春小麦品种(系)及北方冬麦区的17个冬小麦品种(系)D染色体组的遗传多样性进行了分析. 结果显示, 23个微卫星引物在23份材料间共扩增出65个等位基因, 平均每个引物为2.9个. 分析发现, 冬小麦群体内检测到的等位基因数(60个)及平均遗传距离(0.4504)明显高于春小麦(48  相似文献   

15.
Use of diverse germplasm is a key factor which allows high level of resolution due to extensive recombination in the history. Therefore, population used in association mapping should posses as many phenotypes as possible. One of the methods to obtain most of the phenotypes is to construct the core collection. The ICRISAT foxtail millet core collection consisting of 155 accessions was genotyped using 72 simple sequence repeat (SSR) markers to investigate the genetic diversity, population structure and linkage disequilibrium (LD). A high degree of molecular diversity among the accessions was found, with an average of 16.69 alleles per locus. STRUCTURE analyses classify the accessions into four subpopulations (SP) based on SSR allelic diversity. The Neighbor joining clustering and the principal coordinate analysis were in accordance with the racial classification. The distribution of molecular genetic variation among and within the four SP and three races showed high degree of variability within each group, and low level of genetic distance (GD) among the groups. LD decay of <40 cM of GD in foxtail millet core collection was observed, which suggests that it could be possible to achieve resolution down to the 40 cM level. From this investigation, it is evident that the foxtail millet core collection developed at ICRISAT is very diverse and could be a valuable resource for trait association mapping, crop breeding and germplasm management.  相似文献   

16.
Spike density (SD), an important spike morphological trait associated with wheat yield, is the spikelet number per spike (SNS) divided by spike length (SL). In this study, phenotypic data from eight environments were collected and a recombinant inbred line population (RIL) constructed by the wheat line 20828 and the cultivar 'Chuannong16' and a Wheat55K SNP array-based constructed genetic linkage map were used to identify SD quantitative trait locus (QTL). Correlation between SD and other agronomic traits was calculated. Genes associated with plant growth and development for major loci were predicted. The results showed that 24 QTLs associated with SD were detected in eight environments. Among them, three major QTL, namely QSd.sicau-5B.2, QSd.sicau-2D.3 and QSd.sicau-4B.1, explained up to 35.62%, 14.21% and 11.23% of phenotypic variation, respectively. The positive alleles of them were all derived from 'Chuannong16'. The significant relationships between SD and other agronomic traits were detected and discussed. Taken together, the stably expressed SD QTL under different environments identified in this study provided theoretical guidance for further fine mapping and germplasm improvement.  相似文献   

17.
山东省近期育成小麦品种遗传多样性的SSR分析   总被引：1，自引：0，他引：1  
为了揭示山东省近年来小麦品种的遗传多样性.选用分布于小麦21条染色体上的68个SSR引物,对44个山东省小麦品种进行了遗传多样性分析.共检测到248个等位基因,每对引物的等位基因数变幅为2～9个,平均为3.65个.每个SSR位点的多态性信息量(PIC)变化范围为0.087～0.837,平均为0.562.44个品种间的遗...  相似文献   

18.
Usually, mapping studies in potato are performed with segregating populations from crosses between highly heterozygous diploid or tetraploid parents. These studies are hampered by a high level of genetic background noise due to the numerous segregating alleles, with a maximum of eight per locus. In the present study, we aimed to increase the mapping efficiency by using progenies from diploid inbred populations in which at most two alleles segregate. Selfed progenies were generated from a cross between S. tuberosum (D2; a highly heterozygous diploid) and S. chacoense (DS; a homozygous diploid clone) containing the self-incompatibility overcoming S locus inhibitor (Sli-gene). The Sli-gene enables self-pollination and the generation of selfed progenies. One F2 population was used to map several quality traits, such as tuber shape, flesh and skin color. Quantitative trait loci were identified for almost all traits under investigation. The identified loci partially coincided with known mapped loci and partially identified new loci. Nine F3 populations were used to validate the QTLs and monitor the overall increase in the homozygosity level.  相似文献   

19.
大麦遗传多样性及连锁不平衡分析   总被引：1，自引：0，他引：1  
为了合理评价引进种质资源,为大麦基因发掘及育种组合配置提供依据,选用分布于全基因组的64个SSR标记,对221份大麦材料进行了基因型分析。共检测到192个等位变异,变幅为2~7个;基因频率变异范围为0.0090~0.9729,平均0.3333;全部位点的基因多样性变化范围在0.0528~0.7807,平均0.4813;多态性信息含量(PIC)变异范围在0.0514~0.7464,平均0.4113。供试材料间遗传相似系数变幅为0.4844~0.9792,平均0.7023。221份材料被划分成两大群7个亚群,国内地方品种与1份北京品种为一大群,国内育种品种与所有国外引进品种为另一群。遗传结构分析与聚类结果基本一致,两大类群间的遗传距离为0.3358,且第二大群多样性比第一大群丰富。2016个SSR位点成对组合中,不论共线性组合还是非共线性组合,都存在一定程度的连锁不平衡(LD)。D′统计概率(P<0.01)支持的LD成对位点830个,占全部位点组合的41.2%,D′平均值为0.4,整体LD水平较高。栽培品种的LD水平高于地方品种,且现代遗传改良的目标性状集中于2H、4H、6H和7H染色体。  相似文献   

20.
Flag leaf-related traits (FLRTs) are determinant traits affecting plant architecture and yield potential in wheat (Triticum aestivum L.). In this study, three related recombinant inbred line (RIL) populations with a common female parent were developed to identify quantitative trait loci (QTL) for flag leaf width (FLW), length (FLL), and area (FLA) in four environments. A total of 31 QTL were detected in four environments. Two QTL for FLL on chromosomes 3B and 4A (QFll-3B and QFll-4A) and one for FLW on chromosome 2A (QFlw-2A) were major stable QTL. Ten QTL clusters (C1–C10) simultaneously controlling FLRTs and yield-related traits (YRTs) were identified. To investigate the genetic relationship between FLRTs and YRTs, correlation analysis was conducted. FLRTs were found to be positively correlated with YRTs especially with kernel weight per spike and kernel number per spike in all the three RIL populations and negatively correlated with spike number per plant. Appropriate flag leaf size could benefit the formation of high yield potential. This study laid a genetic foundation for improving yield potential in wheat molecular breeding programs.  相似文献   

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