Classical Mapping Research Articles

Dissociating frontal and temporal correlates of phonological and semantic fluency in a large sample of left hemisphere stroke patients.

Previous lesion studies suggest that semantic and phonological fluency are differentially subserved by distinct brain regions in the left temporal and the left frontal cortex, respectively. However, as of yet, this often implied double dissociation has not been explicitly investigated due to mainly two reasons: (i) the lack of sufficiently large samples of brain-lesioned patients that underwent assessment of the two fluency variants and (ii) the lack of tools to assess interactions in factorial analyses of non-normally distributed behavioral data. In addition, previous studies did not control for task resource artifacts potentially introduced by the generally higher task difficulty of phonological compared to semantic fluency.We addressed these issues by task-difficulty adjusted assessment of semantic and phonological fluency in 85 chronic patients with ischemic stroke of the left middle cerebral artery. For classical region-based lesion-behavior mapping patients were grouped with respect to their primary lesion location. Building on the extension of the non-parametric Brunner-Munzel rank-order test to multi-factorial designs, ANOVA-type analyses revealed a significant two-way interaction for cue type (semantic vs. phonological) by lesion location (left temporal vs. left frontal vs. other as stroke control group). Subsequent contrast analyses further confirmed the proposed double dissociation by demonstrating that (i) compared to stroke controls, left temporal lesions led to significant impairments in semantic but not in phonological fluency, whereas left frontal lesions led to significant impairments in phonological but not in semantic fluency, and that (ii) patients with frontal lesions showed significantly poorer performance in phonological than in semantic fluency, whereas patients with temporal lesions showed significantly poorer performance in semantic than in phonological fluency.The anatomical specificity of these findings was further assessed in voxel-based lesion-behavior mapping analyses using the multi-factorial extension of the Brunner-Munzel test. Voxel-wise ANOVA-type analyses identified circumscribed parts of left inferior frontal gyrus and left superior and middle temporal gyrus that significantly double-dissociated with respect to their differential contribution to phonological and semantic fluency, respectively. Furthermore, a main effect of lesion with significant impairments in both fluency types was found in left inferior frontal regions adjacent to but not overlapping with those showing the differential effect for phonological fluency.The present study hence not only provides first explicit evidence for the anatomical double dissociation in verbal fluency at the group level but also clearly underlines that its formulation constitutes an oversimplification as parts of left frontal cortex appear to contribute to both semantic and phonological fluency.

Diagnosing Metabolic Syndrome Using Genetically Optimised Bayesian ARTMAP

Metabolic Syndrome (MetS) constitutes of metabolic abnormalities that lead to non-communicable diseases, such as type II diabetes, cardiovascular diseases, and cancer. Early and accurate diagnosis of this abnormality is required to prevent its further progression to these diseases. This paper aims to diagnose the risk of MetS using a new non-clinical approach called “genetically optimized Bayesian adaptive resonance theory mapping” (GOBAM). We evolve the Bayesian adaptive resonance theory mapping (BAM) by using genetic algorithm to optimize the parameters of BAM and its training input sequence. We use the GOBAM algorithm to classify individuals as either being at risk of MetS or not at risk of MetS with a related posterior probability, which ranges between 0 and 1. A data set of 11 237 Malaysians from the CLUSTer study stratified by age and gender into four subcategories was used to evaluate the proposed GOBAM algorithm. The comparative evaluation of our results suggested that the GOBAM performs significantly better than other classical adaptive resonance theory mapping models on the area under the receiver operating characteristic curves (AUC) and others criteria. Our algorithm gives an AUC of 86.42 %, 87.04 %, 91.08 %, and 89.24 % for the young female, middle aged female, young male, and middle-aged male subcategories, respectively. The proposed model can be used to support medical practitioners in accurate and early diagnosis of MetS.

Atlas web mapping of hazardous hydrometeorological events in the Ural Prikamye region

The paper presents the designing and development of the Atlas Information System (AIS) of hazardous hydrometeorological events (HHME) in the Ural Prikamye region. AIS integrates classic mapping approaches and modern web mapping service technologies. AIS information basis includes several data sources, both ground-based and satellite observations. The basic techniques and algorithms for mapping of HHME spatiotemporal distribution and the main AIS content are briefly described. Examples are provided of periodicity and intensity mapping of various HHME types, as well as zoning results of the study area in terms of prevailing types of hazardous weather events. The AIS content functionality is considered, including various techniques of data visualization, connection to external databases, search and query generation, building of cartograms and structural diagrams. AIS is published in open access as cartographic web map service (http://ais.maps.psu.ru). The main result of the project for the Perm region is the development of the unique reference and information cartographic resource on the current climatic conditions of the region, its typical HHME, their spatiotemporal distribution, as well as HHME-related damage.

A finite strain incremental-secant homogenization model for elasto-plastic composites

This paper presents a finite strain extension of the incremental-secant mean-field homogenization (MFH) formulation for two-phase elasto-plastic composites. The formulation of the local finite strain elasto-plastic constitutive equations of each phase is based on a multiplicative decomposition of the deformation gradient as suggested by Simo in (Computer Methods in Applied Mechanics and Engineering, 99(1):61–112, 1992.). The latter has proposed algorithms which preserve the classical return mapping schemes of the infinitesimal theory by using principal Kirchhoff stresses and logarithmic eigenvalues of the left elastic Cauchy–Green strain. Relying on this property, we show that, by considering a quadratic logarithmic free energy and J2-flow theory at the local level, infinitesimal strain incremental-secant MFH is readily extended to finite strains. The proposed formulation and corresponding numerical algorithms are then presented. Finally, the predictions are illustrated with several numerical simulations which are verified against full-field finite element simulations of composite cells, demonstrating that the micro-mechanically based approach is able to predict the influence of the micro-structure and of its evolution on the macroscopic properties in a very cost-effective manner.

Information theory to tachycardia therapy: electrogram entropy predicts diastolic microstructure of reentrant ventricular tachycardia.

There is no known strategy to differentiate which multicomponent electrograms in sinus rhythm maintain reentrant ventricular tachycardia (VT). Low entropy in the voltage breakdown of a multicomponent electrogram can localize conditions suitable for reentry but has not been validated against the classic VT activation mapping. We examined whether low entropy in a late and diversely activated ventricular scar region characterizes and differentiates the diastolic path of VT and represents protected tissue channels devoid of side branches. Intraoperative bipolar electrogram (BiEGM) activation and entropy maps were obtained during sinus rhythm in 17 patients with ischemic cardiomyopathy and compared with diastolic activation paths of VT (total of 39 VTs). Mathematical modeling of a zigzag main channel with side branches was also used to further validate structural representation of low entropy in the ventricular scar. A median of one region per patient (range: 1-2 regions) was identified in sinus rhythm, in which BiEGM with the latest mean activation time and adjacent minimum entropy were assembled together in a high-activation dispersion region. These regions accurately recognized diastolic paths of 34 VTs, often to multiple inducible VTs within a single individual arrhythmogenic region. In mathematical modeling, side branching from the main channel had a strong influence on the BiEGM composition along the main channel. The BiEGM obtained from a long unbranched channel had the lowest entropy compared with those with multiple side branches. In conclusion, among a population of multicomponent sinus electrograms, those that demonstrate low entropy and are delayed colocalize to critical long-protected channels of VT. This information is pertinent for planning VT ablation in sinus rhythm. NEW & NOTEWORTHY Entropy is a measure to quantify breakdown in information. Electrograms from a protected tissue channel can only possess a few states in their voltage and thus less information. In contrast, current-load interactions from side branches in unprotected channels introduce a number of dissimilar voltage deflections and thus high information. We compare here a mapping approach based on entropy against a rigorous reference standard of activation mapping during VT and entropy was assessed in sinus rhythm.

Genome-wide scans of selection highlight the impact of biotic and abiotic constraints in natural populations of the model grass Brachypodium distachyon.

Grasses are essential plants for ecosystem functioning. Quantifying the selective pressures that act on natural variation in grass species is therefore essential regarding biodiversity maintenance. In this study, we investigate the selection pressures that act on two distinct populations of the grass model Brachypodium distachyon without prior knowledge about the traits under selection. We took advantage of whole-genome sequencing data produced for 44 natural accessions of B.distachyon and used complementary genome-wide selection scans (GWSS) methods to detect genomic regions under balancing and positive selection. We show that selection is shaping genetic diversity at multiple temporal and spatial scales in this species, and affects different genomic regions across the two populations. Gene ontology annotation of candidate genes reveals that pathogens may constitute important factors of positive and balancing selection in B.distachyon. We eventually cross-validated our results with quantitative trait locus data available for leaf-rust resistance in this species and demonstrate that, when paired with classical trait mapping, GWSS can help pinpointing candidate genes for further molecular validation. Thanks to a near base-perfect reference genome and the large collection of freely available natural accessions collected across its natural range, B.distachyon appears as a prime system for studies in ecology, population genomics and evolutionary biology.

The Arsenic Fault-Pathfinder: A Complementary Tool to Improve Structural Models in Mining

In a mining operation, the structural model is considered as a first-order data required for planning. During the start-up and in-depth expansion of an operation, whether the case is open-pit or underground, the structural model must be systematically updated because most common failure mechanisms of a rock mass are generally controlled by geological discontinuities. This update represents one of the main responsibilities for structural geologists and mine engineers. For that purpose, our study presents a geochemically-developed tool based on the tridimensional (3-D) distribution of arsenic concentrations, which have been quantified with a very high-density of blast-holes sampling points throughout an open pit operation. Our results show that the arsenic spatial distribution clearly denotes alignments that match with faults that were previously recognized by classical direct mapping techniques. Consequently, the 3-D arsenic distribution can be used to endorse the existence and even more the real persistence of structures as well as the cross-cutting relationships between faults. In conclusion, by linking the arsenic fault-pathfinder tool to direct on field fault mapping, it is possible to improve structural models at mine scale, focusing on geotechnical design and management, with a direct impact in the generation of safety mining activities.

Toward Accurate Quantitative Elasticity Mapping of Rigid Nanomaterials by Atomic Force Microscopy: Effect of Acquisition Frequency, Loading Force, and Tip Geometry

Atomic force microscopy (AFM) has emerged as a popular tool for the mechanical mapping of soft nanomaterials due to its high spatial and force resolution. Its applications in rigid nanomaterials, however, have been underexplored. In this work, we studied elasticity mapping of common rigid materials by AFM, with a focus on factors that affect the accuracy of elasticity measurements. We demonstrated the advantages in speed and noise level by using high frequency mechanical mapping compared to the classical force volume mapping. We studied loading force dependency, and observed a consistent pattern on all materials, where measured elasticity increased with loading force before stabilizing. Tip radius was found to have a major impact on the accuracy of measured elasticity. The blunt tip with 200 nm radius measured elasticity with deviation from nominal values up to 13% in different materials, in contrast to 122% by the sharp tip with 40 nm radius. Plastic deformation is believed to be the major reason for this difference. Sharp tips, however, still hold advantages in resolution and imaging capability for nanomaterials.

Stability analysis of time varying delayed stochastic Hopfield neural networks in numerical simulation

Abstract This paper is concerned with the stability analysis of time varying delayed stochastic Hopfield neural networks in numerical simulation . To achieve our expected conclusions, we will reform the classical contractive mapping principle in functional analysis, with some modifications, to adapt to our conditions and both the continuous and the discrete delayed models. Under the reasonable conditions, it is shown that, the Euler–Maruyama numerical scheme is mean square exponentially stable of exact solution dependent of step size. Further more, it is also shown that the backward Euler–Maruyama numerical scheme can share the mean square exponential stability of the exact solution independent of step size under the same conditions.

Kernel Foveated Rendering

Foveated rendering coupled with eye-tracking has the potential to dramatically accelerate interactive 3D graphics with minimal loss of perceptual detail. In this paper, we parameterize foveated rendering by embedding polynomial kernel functions in the classic log-polar mapping. Our GPU-driven technique uses closed-form, parameterized foveation that mimics the distribution of photoreceptors in the human retina. We present a simple two-pass kernel foveated rendering (KFR) pipeline that maps well onto modern GPUs. In the first pass, we compute the kernel log-polar transformation and render to a reduced-resolution buffer. In the second pass, we carry out the inverse-log-polar transformation with anti-aliasing to map the reduced-resolution rendering to the full-resolution screen. We have carried out pilot and formal user studies to empirically identify the KFR parameters. We observe a 2.8X -- 3.2X speedup in rendering on 4K UHD (2160p) displays with minimal perceptual loss of detail. The relevance of eye-tracking-guided kernel foveated rendering can only increase as the anticipated rise of display resolution makes it ever more difficult to resolve the mutually conflicting goals of interactive rendering and perceptual realism.

The Impact of Genetic Changes during Crop Domestication

Humans have domesticated hundreds of plant and animal species as sources of food, fiber, forage, and tools over the past 12,000 years, with manifold effects on both human society and the genetic structure of the domesticated species. The outcomes of crop domestication were shaped by selection driven by human preferences, cultivation practices, and agricultural environments, as well as other population genetic processes flowing from the ensuing reduction in effective population size. It is obvious that any selection imposes a reduction of diversity, favoring preferred genotypes, such as nonshattering seeds or increased palatability. Furthermore, agricultural practices greatly reduced effective population sizes of crops, allowing genetic drift to alter genotype frequencies. Current advances in molecular technologies, particularly of genome sequencing, provide evidence of human selection acting on numerous loci during and after crop domestication. Population-level molecular analyses also enable us to clarify the demographic histories of the domestication process itself, which, together with expanded archaeological studies, can illuminate the origins of crops. Domesticated plant species are found in 160 taxonomic families. Approximately 2500 species have undergone some degree of domestication, and 250 species are considered to be fully domesticated. The evolutionary trajectory from wild to crop species is a complex process. Archaeological records suggest that there was a period of predomestication cultivation while humans first began the deliberate planting of wild stands that had favorable traits. Later, crops likely diversified as they were grown in new areas, sometimes beyond the climatic niche of their wild relatives. However, the speed and level of human intentionality during domestication remains a topic of active discussion. These processes led to the so-called domestication syndrome, that is, a group of traits that can arise through human preferences for ease of harvest and growth advantages under human propagation. These traits included reduced dispersal ability of seeds and fruits, changes to plant structure, and changes to plant defensive characteristics and palatability. Domestication implies the action of selective sweeps on standing genetic variation, as well as new genetic variation introduced via mutation or introgression. Furthermore, genetic bottlenecks during domestication or during founding events as crops moved away from their centers of origin may have further altered gene pools. To date, a few hundred genes and loci have been identified by classical genetic and association mapping as targets of domestication and postdomestication divergence. However, only a few of these have been characterized, and for even fewer is the role of the wild-type allele in natural populations understood. After domestication, only favorable haplotypes are retained around selected genes, which creates a genetic valley with extremely low genetic diversity. These “selective sweeps” can allow mildly deleterious alleles to come to fixation and may create a genetic load in the cultivated gene pool. Although the population-wide genomic consequences of domestication offer several predictions for levels of the genetic diversity in crops, our understanding of how this diversity corresponds to nutritional aspects of crops is not well understood. Many studies have found that modern cultivars have lower levels of key micronutrients and vitamins. We suspect that selection for palatability and increased yield at domestication and during postdomestication divergence exacerbated the low nutrient levels of many crops, although relatively little work has examined this question. Lack of diversity in modern germplasm may further limit our capacity to breed for higher nutrient levels, although little effort has gone into this beyond a handful of staple crops. This is an area where an understanding of domestication across many crop taxa may provide the necessary insight for breeding more nutritious crops in a rapidly changing world.

Assessment of genetic diversity in Egyptian barley (Hordeum vulgare L.) genotypes using SSR and SNP markers

A barley core collection can be studied extensively and the derived information can be used to identify loci/genes for the genetic improvement of quantitative and qualitative traits. To assess genetic diversity, allelic variation and population structure of Egyptian barley, 134 barley genotypes collected from a different region along with 19 cultivated genotypes obtained from of the Egyptian Agricultural Research Center. All genotypes were analyzed with 261 polymorphic SSR and SNP alleles. The mean number of alleles per locus was 4 and PIC was 0.49, while the level of genetic diversity was 0.55 ranging from 0.03 to 0.82. The genotypes were assigned to three subpopulations that were consistent with their origins. The genetic variation within population was higher (51%) than among population at the molecular levels (FST = 0.491 when P < 0.10). The level of polymorphic variation was highest in subpopulations-II, due to collected from different regions with different ear-types thus, expected to contain more diversity than local genotypes in subpopulations-I and subpopulations-III. The structured study found that the 153 barley genotypes are in harmony with clustering approaches using the SSR and SNP genotypic data in a neighbor-joining tree and principal components analysis, which identified three subpopulations. These results demonstrated genetic diversity among the Egyptian barley genotypes can be applied to suggest approaches, such as association analysis, classical mapping population development, and parental line selection in breeding programs. Therefore, it is necessary to use the exotic genotypes as the genetic resources for developing new barley cultivars in Egypt.

R2RS: schema-based relational databases mapping to linked datasets

Background/Objectives: The vast amounts of high-quality data stored in relational databases (RDB) is the primary resources for Linked Open Data (LOD) datasets. This paper proposes a schema-based mapping approach from RDB to RDF, which provides succinct and efficient mapping.Methods/Statistical analysis: The various approaches, languages and tools for mapping RDB to LOD have been proposed in the recent years. This paper surveys and analyzes classic mapping approach and language such as Direct Mapping and R2RML. The mapping approaches can be categorized by means of their data modeling. After analyzing the conventional RDB-RDF mapping methods, this paper proposes a new mapping method and discusses its typical features and applications.Findings: There are two types of mapping approaches for the translation of RDB to RDF: instance-based and schema-based mapping approaches. The instance-based mapping approaches generate large amounts of RDF graphs by means of mapping rules. These approaches causes data redundancy since the same data is stored in two ways of RDB and RDF. It is very easy to bring the data inconsistence problem when data update operations occur. The schema-based mapping approaches can effectively avoid data redundancy since the mapping can be accomplished in the conceptual schema level.The architecture of SPARQL endpoint based on schema mapping approach consists of five phases:Generation of mapping description based on mapping rules.SPARQL query statements for RDF graph patterns.Translation of SPARQL query into SQL query.Execution of SQL query in RDB.Interpretation of SQL query result into JSON-LD format.Experiments show the schema-based mapping approach is a straightforward, succinct and efficient mapping method for RDB2RDF.Improvements/Applications: This paper proposes a schema-based mapping approach called R2RS, which shows better performance than the conventional mapping methods. In addition, R2RS also provides the efficient implementation of SPARQL endpoint in RDB.

MQTL-seq and classical mapping implicates the role of an AT-HOOK MOTIF CONTAINING NUCLEAR LOCALIZED (AHL) family gene in Ascochyta blight resistance of chickpea.

Ascochyta blight (AB) caused by the fungal pathogen Ascochyta rabiei is a serious foliar disease of chickpea (Cicer arietinum L.). Despite many genetic studies on chickpea-Ascochyta interaction, genome-wide scan of chickpea for the identification of AB-associated quantitative trait loci (QTLs) and their gene(s) has not been accomplished. To elucidate narrow QTLs for AB resistance, here, we report the use of multiple QTL-sequencing approach on 2 sets of extreme AB phenotype bulks derived from Cicer intraspecific and interspecific crosses. Two major QTLs, qABR4.1 and qABR4.2, and a minor QTL, qABR4.3, were identified on assembled chickpea pseudomolecule 4. We narrowed qABR4.1 to a "robust region" at 4.568-4.618Mb through mapping on a larger intraspecific cross-derived population and comparative analysis. Among 4 genes, the CaAHL18 gene showed higher expression under Ascochyta stress in AB resistant parent suggesting that it is the candidate gene under "robust qABR4.1." Dual-luciferase assay with CaAHL18 polymorphic cis-regulatory sequences showed that allelic variation is associated with higher expression. Thus, our findings on chickpea-Ascochyta interaction have narrowed down AB resistance associated QTLs on chickpea physical map. The narrowed QTLs and gene-associated markers will help in biotechnological and breeding programs for chickpea improvement.

Combining QTL-seq and linkage mapping to fine map a wild soybean allele characteristic of greater plant height

BackgroundPlant height (PH) is an important agronomic trait and is closely related to yield in soybean [Glycine max (L.) Merr.]. Previous studies have identified many QTLs for PH. Due to the complex genetic background of PH in soybean, there are few reports on its fine mapping.ResultsIn this study, we used a mapping population derived from a cross between a chromosome segment substitution line CSSL3228 (donor N24852 (G. Soja), a receptor NN1138–2 (G. max)) and NN1138–2 to fine map a wild soybean allele of greater PH by QTL-seq and linkage mapping. We identified a QTL for PH in a 1.73 Mb region on soybean chromosome 13 through QTL-seq, which was confirmed by SSR marker-based classical QTL mapping in the mapping population. The linkage analysis showed that the QTLs of PH were located between the SSR markers BARCSOYSSR_13_1417 and BARCSOYSSR_13_1421 on chromosome 13, and the physical distance was 69.3 kb. RT-PCR and sequence analysis of possible candidate genes showed that Glyma.13 g249400 revealed significantly higher expression in higher PH genotypes, and the gene existed 6 differences in the amino acids encoding between the two parents.ConclusionsData presented here provide support for Glyma.13 g249400 as a possible candidate genes for higher PH in wild soybean line N24852.

EXIT-Chart Aided Design of Row-Permutation Assisted Twin-Interleaver BICM-ID

Twin-interleaver bit-interleaved LDPC coded modulation (BICM) has been widely adopted and studied in the context of digital terrestrial transmission (DTT) systems. Extrinsic-information transfer (EXIT) charts have been used as an analysis tool to evaluate the iterative decoding performance and to design a twin-interleaver BICM system. Since BICM using iterative decoding (BICM-ID) exhibits capacity-approaching decoding performance, developing the conventional twin-interleaver BICM DTT system to a BICM-ID system has also been attempted. When considering the twin-interleaver BICM-ID systems, there are a couple of aspects that should be taken into account. We will demonstrate that anti-Gray mapping should be adopted for improving the iterative decoding performance instead of the classic Gray symbol mapping. However, the previous literature related to designing the associated row-permutation interleaver (RPI) was mainly focused on BICM systems relying on Gray mapping. Hence, we will design the RPI of the twin-interleaver BICM-ID DTT systems using an anti-Gray mapping. Explicitly, we use: 1) the EXIT-chart analysis that accurately visualizes the overall iterative decoding and demapping performance of the twin-interleaver BICM-ID DTT systems using anti-Gray mapping and 2) a preprocessing stage for eliminating duplicate RPI candidates by using a parameter that roughly predicts the EXIT-chart analysis result before the EXIT-chart analysis is involved. By the elimination of the duplicates, over 99% of the initial candidates of the RPIs can be removed from the original M! candidates, where M stands for the number of modulated bits in a symbol. Given this drastically reduced number of candidates, the proposed design method finds novel RPIs, having superior bit-error ratio performances over the conventional RPIs in the context of the DVB-T2 standard.

Hyperelliptic graphs and the period mapping on outer space

The period mapping assigns to each rank n, marked metric graph Gamma a positive definite quadratic form on H_1(Gamma). This defines maps Phi* and Phi on Culler--Vogtmann's outer space CV_n, and its Torelli space quotient T_n, respectively. The map Phi is a free group analog of the classical period mapping that sends a marked Riemann surface to its Jacobian. In this paper, we analyze the fibers of Phi in T_n, showing that they are aspherical, pi_1-injective subspaces. Metric graphs admitting a 'hyperelliptic involution' play an important role in the structure of Phi, leading us to define the hyperelliptic Torelli group, ST(n) < Out(F_n). We obtain generators for ST(n), and apply them to show that the connected components of the locus of 'hyperelliptic' graphs in T_n become simply-connected when certain degenerate graphs at infinity are added.

The open mapping principle for partial actions of Polish groups

We present a extension of the classical open mapping principle and Effros' theorem for Polish group actions to the context of partial group actions.

Successive approximations for common fixed points of a family of $$\alpha $$ α -nonexpansive mappings

In this paper, we consider the Halpern iteration for $$\alpha $$ -nonexpansive mapping semigroups; such semigroups contain classical nonexpansive mapping semigroups as special cases. The strong convergence theorems of Halpern iteration sequence are shown for finding a common fixed point of an $$\alpha $$ -nonexpansive semigroup, which exactly is a metric projection point of the anchor point u to the common fixed point set of such semigroups. Furthermore, the strong convergence of the Halpern iteration for an $$\alpha $$ -nonexpansive mapping sequence is given also.

QTL-seq for rapid identification of candidate genes for flowering time in broccoli×cabbage.

A major QTL controlling early flowering in broccoli×cabbage was identified by marker analysis and next-generation sequencing, corresponding to GRF6 gene conditioning flowering time in Arabidopsis. Flowering is an important agronomic trait for hybrid production in broccoli and cabbage, but the genetic mechanism underlying this process is unknown. In this study, segregation analysis with BC1P1, BC1P2, F2, and F2:3 populations derived from a cross between two inbred lines "195" (late-flowering) and "93219" (early flowering) suggested that flowering time is a quantitative trait. Next, employing a next-generation sequencing-based whole-genome QTL-seq strategy, we identified a major genomic region harboring a robust flowering time QTL using an F2 mapping population, designated Ef2.1 on cabbage chromosome 2 for early flowering. Ef2.1 was further validated by indel (insertion or deletion) marker-based classical QTL mapping, explaining 51.5% (LOD=37.67) and 54.0% (LOD=40.5) of the phenotypic variation in F2 and F2:3 populations, respectively. Combined QTL-seq and classical QTL analysis narrowed down Ef1.1 to a 228-kb genomic region containing 29 genes. A cabbage gene, Bol024659, was identified in this region, which is a homolog of GRF6, a major gene regulating flowering in Arabidopsis, and was designated BolGRF6. qRT-PCR study of the expression level of BolGRF6 revealed significantly higher expression in the early flowering genotypes. Taken together, our results provide support for BolGRF6 as a possible candidate gene for early flowering in the broccoli line 93219. The identified candidate genomic regions and genes may be useful for molecular breeding to improve broccoli and cabbage flowering times.