혈청 내 존재하는 효소 중 Glutamic pyruvic transaminase(GPT)는 근육이나 간세포의 손상에 대한 임상 화학적 지표로 사용 된다. 본 연구는 Landrace와 한국재래돼지의 F2 교잡 축군(N=1,105)에 대해 Porcine SNP 60K beadchip을 사용하여 유전자형 분석을 실시하고, GPT 형질과의 관련성을 검증하기 위해 Genome-Wide Association Study(GWAS)를 수행하였다. F2 교잡축군의 가계구조를 보정한 GWAS를 수행하기 위하여 혼합모형과 회귀분석을 조합한 GRAMMAR방법을 관련성 분석에 사용 하였다. 유의성 있는 SNP 표지들은 Sus scrofa chromosome(SSC) 6, 7, 그리고 13에서 동정되었다. 이들유의성 있는 SNP marker들에 가장 근접한 염색체상 위치의 유전자를 그 유전자의 기능을 고려하여 SSC7에서 2개의 위치후보유전자(BCL11B, AHNAK2)를 선정하였다. Pyrosequencing법을 통하여 이 들유전자 내에 존재하는 4개 SNP 표지들의 유전자형을 분석하여 GPT 형질간의 관련성 분석에 이용하였다. 관련성 분석결과, BCL11B g.267 T>C에서 nominal P=7.23×10-8 과 AHNAK2 g.1439 C>T에서 nominal P=5.64×10-6, g.1736 C>A에서 nominal P=3.51×10-6의 결과를 얻었다. 이 들 중 가장 유의한 결과를 얻은 BCL11B 유전자의 g.267 T>C SNP 표지는 추가 연구를 통하여 혈청 GPT 변이에 영향을 미치는 위치상 후보 유전자 표지로 사용 되어 질 수 있을 것이라 사료되어진다.

돼지의 체장, 체폭, 체중 등의 연속적인 변이를 가지는 양적형질에 속하는 형질인 성장형질은 양돈업에 있어서 생산성과 수익성에 직결된 중요한 경제 형질이다. 성장형질로는 일당증체량, 등지방두께, 등심단면적 및 도체품질 등이 있으며, 그중에서 등심단면적과 관련이 있는 후보 유전자를 Genome-wide 수준에서 선발하기 위하여 Illumina 사의 Porcine SNP 60K chip을 이용하여 순종 Landrace 집단(수컷 : 50두, 암컷 : 440두)을 분석하였다. Plink program을 이용하여 filtering 과정을 거쳐 최종적으로 31,960개의 SNP marker를 선별하였으며, Genome-wide 임계수준을 bonferroni correction (i.e.1/31957=3.12×10-5)을 이용해서 결정했을 때, SSC16에서 유의성 있는 4개의 SNP marker들을 발견하였다. 이 중 가장 유의성 있는 SNP marker인 DRGA0016148(P=1.38×10-5)와 근접한 후보유전자로 PDE4D를 선정하였고, PDE4D에서 2개(g.9870 T>C, g3976 C>T)의 SNP를 탐색하였다. 본 연구에서는 Genome-wide association study (GWAS)를 이용하여 등심단면적과 관련성이 있는 SNP를 선발하여, 등심단면적과 후보유전자 PDE4D와의 관련성을 규명하고자 연구를 실시하였으나, PDE4D g.9870 T>C 에서는 Hardy-weinberg equilibrium P-value 0.7581로 음의 상관관계를 나타내었으며, PDE4D g.3976 C>T에서는 모두 호모타입이 확인되었다.

본 연구는 농촌진흥청 국립축산과학원에서 사육중인 제주재래돼지와 랜드레이스의 상호교차교배를 통해 생산된 417두의 F2집단을 대상으로 성장형질(생시체중, 3주령 체중, 10주령 체중, 20주령 체중)을 측정하고, 개체별 혈액으로부터 Illumina Porcine SNP 60k BeadChip을 이용하여 유전자형 분석을 실시하여 성장형질과 유전체 전장의 단일염기다형의 유전자형 간에 연관성을 알아보았다. 단일연기다형의 유전자형 분석은 돼지의 성염색체를 제외한 18개의 상염색체 내에 나타난 52,574개의 SNP표지인자 중다형성이 나타나지 않은 7,564개의 표지인자, 모든 개체에서 이형으로 나타난 47개 표지인자 및 결측률이 10 % 이상인 1,830개의 표지인자가 나타나 분석에 앞서 사전 제거를 실시하였으며, 남은 44,133개의 표지인자를 체중형질과 표지인자간 연관성 분석하는데 이용하였다. 체중에 영향하는 고정효과에 대해 일반선형모형을 설정하여 사전 보정을 실시하였으며, 여기서 얻어진 잔차값을 이용하여 표지인자와 월령별 체중간의 연관성 분석을 실시하였다. 분석결과 전장의 유전체 정보 중 통계적 판단의 오류를 고려하여 연관성이 강한(p <10-6)표지인자가 생시(BWB), 3주령(BW3), 10주령(BW10) 및 20주령(BW20) 체중에서 각각 657개, 846개, 49개, 122개로 추정되었다. 생시와 3주령 체중에 공통으로 유의적 영향을 하는 표지인자가 286개로 나타났으며, BWB와 BW10에서 5개, BWB와 BW20에서 8개, BW3와 BW10에서 13개, BW3과 BW20에서 11개, BW10과 BW20에서 1개로 나타났다. 또한 염색체별 성장형질에 영향하는 표지인자의 분포를 조사한 결과, 주령별 체중에 영향하는 표지인자는 전장의 유전체에 고르게 분포하는 것으로 조사되었으며, 특히 생시 및 3주령 체중에 영향하는 표지인자는 특정 염색체(SSC9)에서 고도의 통계적 유의차(p <10-15)를 나타내는 유전자 좌위가 있는 것으로 추정되었다.

Knowledge of the chromosomal constitution of the ancestors of modern soybean will complement plant breeding efforts to improve agronomic and economic characteristics of soybean. Variation block (VB)-based comparison using genome-wide insertion/deletion (InDel) markers was used on a diverse panel of 147 soybean cultivars to assess the impact of chromosomal changes during modern breeding. There were identical variation patterns of the examined InDels consistently appearing in the genome parts arising from parental varieties, indicating that soybean chromosomes in descendants should be all determined by genetic reshuffling of VBs inherited from parental chromosomes. Structure analysis of the accessions through the 202 InDels separated the accessions into four subgroups. Gene introgression revealed by the structure analysis agreed with the fact that a limited number of landraces and elite varieties were introduced and used as donors for breeding soybean cultivars in pedigree analysis. Especially, VBs became more reshuffled over time as a result of the breeding process, which resulted in using breeding parents with new VB-types for improving the end-use value of soybean. Therefore, their clustering using the 202 VB-specific InDels is strongly influenced by the difference in breeding ancestors among the subgroups. This indicates that the 202 InDel markers are very useful for genetic study by analyzing the reshuffling patterns of the parental genomes in the descendant.

Magnesium is important not only for the growth of rice itself, but also as an essential micronutrient component of half of the world population who are supported by rice. Here, we performed genome-wide association study (GWAS) with high-resolution density SNPs to identify natural allelic variation in Mg2+ increase from rice set, which is derived from a total 24,368 rice germplasms. The range of the concentration and distribution of Mg2+ in 295 core accessions of brown rice grain were wide, from 18.17mg/L to 57.11mg/L, with mean 39.71mg/L. In particular, GWAS result shows that the high peak found on chromosomes 3 and 11. The new natural variants identified through haplotyping analysis would be useful to develop new rice varieties with improved storage ability of the valuable mineral through the future molecular breeding.

The formation of definitive endoderm (DE) is a fundamental step for the development of the gastrointestinal tract, respiratory tract and endocrine organs. We present a CRISPR-based pooled screening approach to identify genes which contribute to DE induction from hiPSCs in vitro. CRISPR-based pooled genetic screens in mammalian cell culture enable researchers to identify genes required for a cellular phenotype of interest in an unbiased way. To enable a CRISPR-based forward genetic screen for identifying regulatory genes required for DE differentiation from hiPSCs, we performed pooled screens using a human genome-scale CRISPR knockout library. In addition, we performed a transcriptional activation screen using a lentiviral CRISPRa library to identify the downstream targets of the TGF/nodal/activin signaling pathway, which is a key signaling pathway for DE specification. We identified several signaling pathways including TGFβ, Erk, JNK, and CREB pathways are involved with DE differentiation. We suggest that CRISPR-based pooled genetic screens are a useful tool to identify key signaling pathways and genes required for in vitro differentiation processes and are served as a platform to improve differentiation protocols.

Objective of this study was to investigate the difference of cadmium (Cd) levels in rice grains from non-polluted fields and to define the gene associated with Cd uptake for producing safety food. Cd was analyzed by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). The average concentration of Cd in rice grains was 0.943 μg/kg and Cd levels ranged from 0.050 to 5.699 μg/kg. Genome-Wide Association study (GWAS) based on phenotype data for Cd levels was performed. However, results of GWAS were affected by subpopulation structure and caused false positive. Therefore, GWAS for rice ecotypes (temperate Japonica, tropical Japonica, Indica, Aus, Aromatic, and Admixture) was performed to minimize false positive. GWAS results showed that Os01g0611300, Os01g0611900, Os01g0611950, Os01g0612000, Os01g0612200, Os11g0444400, Os11g0444700, Os11g0444800, and Os11g0444900 genes have significant correlation with Cd levels in rice grains. The sequences of these genes were compared to sequence positions of each other gene (haplotype analysis). According to the results of haplotype analysis, Cd levels of non-synonymous group were higher than other groups and sequence of non-synonymous group was similar to that of Indica. These results were corresponding to the previous research result that Cd levels of Indica were higher than Japonica. Therefore, candidate genes detected through GWAS need to be examined by knock-out or cross breeding.

As a first step of mapping genes conferring resistance to the brown planthopper, Nilaparvata lugens Stål, in Gayabyeo using a population derived from a cross between Gayabyeo and Taebaegbyeo, we performed the whole genome resequencing of these two Tongil-type rice varieties. The amount of raw sequence data was about 18.5X109 bp and 17.9X109 bp in Gayabyeo and Taebaegbyeo, respectively. After quality trimming and read mapping onto Nipponbare reference genome sequence, 9.3X109 bp was mapped in Gayabyeo with mapping depth of 25.0X, and 9.5X109 bp was mapped in Taebaegbyeo with mapping depth of 25.5X. Between Gayabyeo and Nipponbare, 1,585,880 SNPs were detected, while 1,416,898 SNPs were detected between Taebaegbyeo and Nipponbare. Between Gayabyeo and Taebaegbyeo, 284,501 SNPs were detected. Among the SNPs between Gayabyeo and Taebaegbyeo, 21.2% were in genic region and 78.8% were in intergenic region. In CDS region, 15,924 SNPs were detected, among which synonymous SNPs covered 47.3% and non-synonymous SNPs covered 52.7%. We designed Cleaved Amplified Polymorphic Sequences (CAPS) markers with SNPs in the restriction enzyme recognition sites, and 20 CAPS markers were tested. Of the 20 markers, 19 markers showed polymorphism and one marker showed monomorphism between Gayabyeo and Taebaegbyeo. It is expected that sufficient DNA markers for mapping genes with a population derived from a cross between Gayabyeo and Taebaegbyeo can be developed based on the results of the study.

The Cucurbitaceae (Cucurbits) family has 825 species in 118 genera, predominantly distributed in tropical and subtropical regions. Major cucurbit crops including cucumber (Cucumis sativa), melon (Cucumis melo), watermelon (Citrullus lanatus), and squash/pumpkin (Cucumis pepo) are important in the human diet and the rural economy. In recent years, large amount of genome information has been analyzed and reported in major cucurbit crops, such as cucumber, melon, and watermelon. To construct high quality reference genome sequence of Korean melon (Chamoe), genomic and transcriptomic sequence data were generated from Korean native (Gotgam) and elite (SW3) Chamoe inbred line using Illumina HiSeq2000 platform. In case of genome analysis, 4,773 scaffolds covering 98% of Gotgam Chamoe were assembled through de novo genome assembly and reference-based assembly. Large number of simple sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs) were detected between two inbred lines and these markers were used for construction of genetic maps and discrimination of cultivars or species. In addition, genome sequence of other Chamoe and melon including Chang Bougi, Sakata’s Sweet, Prescott Fond Blanc and Banana melon will be constructed by de novo genome analysis. Genetic markers of these will also be detected and used for marker-assisted breeding and further analysis to investigate major traits of Chamoe, fruit color and flesh color. In conclusion, the newly constructed reference genome will provide genome information for comparative genomics and breeding of other cucurbit crops.

GWAS (Genome-wide association study) provides a useful to associate phenotypic variation to genetic variation. It has emerged as a powerful approach for identifying genes underlying complex diseases or morphological traits at an unprecedented rate. Despite benefits, there are only a few examples applied in crop plants due to lack of effective genotyping techniques and well prepared resources for developing high density haplotype maps. In this study, 350 core accessions selected from almost 5,000 Capsicum accessions were used for GWAS. We are planning to construct a high-density haplotype map using GBS platform and perform GWAS for various agronomic traits including fruit traits and metabolites related to pungency to identify genes controlling the traits. These results will not only provide a list of candidate loci but also a powerful tools for finding genetic variants that can be directly used for crop improvement and deciphering the genetic architecture of complex traits.

Gene expression is regulated by DNA and histone methylation by DNA and histone methyltransferases, respectively. In animal system, DNA methyltransferase with CG methylation activity is modified by SUMO conjugation and then its activity was increased, which means that the activity of DNA methyltransferase is modulated by posttranslational modification. so Chromatin remodeling is a new concept for expression of controlling of gene function. We thus analyzed the effect of E3 SUMO ligase AtSIZ1 in CMT3 (chromometnylase 3)-mediated genome methylation by next-generation sequencing (NGS), methyl binding domain MeDIP-sequencing and gene analysis using siz1-2 and cmt3 mutants. we carried out CG-enrich analysis by MeDIP sequencing revealed that the methylation level of the genome including transposons was significantly low in siz1-2 mutants compared to wild-type. Result showed the genes regulated by methylation, that genes related of embryo and root development, cellulose metabolism, and post-translational modifications. All of our data indicate that the methyltransfearse activity of CMT3 may be able to be regulated by AtSIZ1 and thereby CMT3-mediated gene expression and plant development also can be controlled by E3 SUMO ligase activity. Besides, our data also suggest that ammonium (NH4+) can stimulate AtSIZ1- and CMT3- mediated DNA methylation.

The control of flowering, transition from vegetative to reproductive stage, is crucial for significant success during plant development. Multiple environmental and developmental signals are transmitted to the shoot apical meristem and converted to local cue to process developmental phage. These crucial process are delicately controlled and regulated by expression of tissue specifically expressed genes involved in inflorescence development. Therefore, it is necessary that molecular mechanism associated with inflorescence development is revealed to understand control of flowering by genome-wide expression pattern of inflorescence specific genes. In this study we used Affymetrix GeneChip Wheat Genome Array for genome-wide analysis of the expressed genes of inflorescence development including apical meristem and developing spikelet to understand the mechanism of floral development in early stage of wheat inflorescence. Moreover, meta-analysis of 1479 microarray dataset of GPL 3802 provided by Gene Expression Omnibus (GEO) was conducted to determine expression pattern of each probe throughout whole life cycle. Based on meta-analysis, we demonstrate inflorescence specific expressed genes in wheat inflorescence including apical meristem, spikelet meristem to understand the mechanism of floral development of wheat inflorescence.

Sessile organism, plants constitutively challenged with pathogens have been developed various strategies for protection, such as preformed and inducible defense mechanisms. Receptor-like Proteins(RLPs) play critical roles in defense response as well as in plant development and growth. The domain structure of RLPs consists of extracellular leucine–rich repeats, a transmembrane domain, and a short cytoplasmic tail. Here, we identified putative 170 RLP genes from pepper genome using in-house bioinformatics pipeline. The distribution of RLPs on pepper pseudomolecule showed uneven spread and a number of RLPs were physically clustered by tandem array in the specific chromosome. Motifs analysis of pepper RLPs showed conserved LRR sequences (LxxLxxLDLxxNxxxGxIP). To understand further functional and evolutionary characteristics, evolutional relationship and gene profiling analysis are on progress.

Plants have evolved elaborate innate immune systems against invading pathogens, such as bacteria, fungi, oomycetes, viruses and insects. Among them, intracellular immune receptors known as nucleotide-binding site and leucine-rich repeat (NB-LRR) play critical roles in effector-triggered immunity (ETI) regarding to plant defense. Here, we identified potential NB-LRR coding sequences from pepper genome using bioinformatics analysis and performed comparative analysis with Solanaceae plants. As a result, we identified 267, 443, and 755 NBS-encoding genes in the genome of tomato, potato, and pepper, respectively. These may indicate that the Solanaceae NB-LRRs were evolved through species-specific unequal-duplication event. Further phylogenetic and clustering analyses revealed that Solanaceae NB-LRRs were classified into the 14 subgroups with 1 TNL and 13 CNL types. We found that the genes in CNL-G1 and CNL-G2 subgroup were highly expanded compared to other subgroup showing a large portion of NB-LRR in pepper genome. Among 755 NB-LRRs in pepper genome, 623 were physically mapped on all 12 pepper chromosome pseudomolecules. Furthermore, a number of NB-LRRs in the same group were physically clustered by tandem array in the specific chromosome. Genome-wide identification of pepper NB-LRR family and their evolutionary analysis could provide an important resource for identification and characterization of genes for breeding of disease resistance crops.

To define whole genome-level of structural variation by ionization energies and radiation doses in plant, the seeds of Ilpum rice cultivar were acutely irradiated with gamma rays (100Gy, 200Gy, and 400Gy) and ion-beams (20Gy, 40Gy, and 80Gy), respectively. Six M1 rice plants were re-sequenced by Hi-Seq2500 with Ilpum cultivar as control. The average sequencing coverage of the individuals was 10.6X, and the average mapping rate to the rice reference genome (IRGSP-1.0) sequence was 96.95%. The individual plants were irradiated with gamma-400Gy and ion-50Gy had highest variation of SNP with 471,837 and 469,147, respectively. The number of insertion/deletion was 77,500 and 77,106, the synonymous and frame-shift were 7,859 and 7,763 in above two individuals. Although high genome variation shown between Ilpum cultivar and irradiated individuals, there were non-correlation between number of variation and radiation doses. However, five individuals, except ion-20Gy, showed 33 common variant blocks (CVBs) spanning 6 Mb in whole rice genome (1.6%). The CVBs were distributed on 12 rice chromosomes, Chromosome 6 had biggest CVB (5 blocks, 1.3Mb), whereas chromosome 9 had smallest CVB (0.01Mb). Total five hundred fifty one genes were in CVBs which can regard radiation sensitive genes or may be regarded as radiation hot spots in rice genome. This study will contribute to the improvement of the radiation mutation breeding research in genetic and genomic aspect.

Rice germplasm collections continue to grow in number and size around the world. Since maintaining and screening such massive resources remain as a great challenge, it is important to establish piratical ways to manage them. A core collection, by definition, refers to a subset of entire population but preserves most of the possible genetic diversity, enhancing the efficiency for germplasm utilizations. Here we reports the whole genome resequencing of the 137 Korean rice core set (KRICE_CORE) that represents 25,604 rice germplasms deposited in Korean genebank of Rural Development Administration (RDA). We implemented the Illumna HiSeq 2000 and 2500 platform to produce short reads and then assembled those with 9.8x depth using Nipponbare as a reference. Comparisons of the sequences with the reference genome yield more than 15 million(M) single nucleotide polymorphisms (SNPs) and 1.3M insertion/deletion (INDELs). Phylogenetic and population analyses using 2,046,529 high quality SNPs successfully assigned each rice accessions to the relevant subgroups, suggesting those SNPs comprehensively capture evolutionary signatures accumulated in rice subpopulations. Furthermore, genome-wide association studies (GWAS) for 4 exemplary agronomic traits from the KRIC_CORE manifest the utility of KRICE_CORE, identifying previously defined gene or novel genetic polymorphisms that potentially regulate the important phenotypes. This study provides strong evidences that the size of KRICE_CORE is small but contains such a high genetic and functional diversity across the genome. Thus those resequencing results will be useful for future breeding, functional and evolutionary studies in the post-genomic era.

The TIFY family is composed of a plant-specific group of genes with diversity of functions. This family represents four subfamily of proteins viz. ZML, TIFY, PPD and JASMONATE ZIM-domain (JAZ) proteins. TIFY proteins especially, JAZ proteins have been reported to perform different biological processes, such as developmental and stresses and hormone responses in Arabidopsis and rice. However, there is no information about this family genes in Brassicaceae. This study identifies 36 TIFY genes in Brassica rapa, an economically important crop species from this family. An extensive in silico analysis through phylogenetic grouping, protein motif organization and intron-exon distribution also confirmed 4 subfamilies of BrTIFY proteins. Out of 35 BrTIFY genes, we identified 21 under JAZ subfamily besides 7 TIFY, 6 ZML and 2 PPD. An extensive expression profiling of 21 BrTIFY JAZs both in tissues and organs of B. rapa revealed differential expression patterns. Almost all the BrTIFY JAZs predominantly expressed in leaves and flower buds. Besides, in a flower stage specific expression analysis we observed 14 BrTIFY JAZs with constitutive expression patterns. This indicates BrTIFY proteins have a strong involvement in the development of B. rapa flowers. Our protein interaction study also reveals the strong association of these proteins with the fertility and defense processes of B. rapa. To elucidate the stress responsiveness of BrTIFY genes, we analyzed the low temperature-treated whole-genome microarray data set and found almost all the BrTIFY JAZs were having variable transcript abundance in two contrasting inbred lines of B. rapa. Subsequently, all 21 BrTIFY JAZs were validated in response to cold stress in the same two lines via qPCR, where 9 genes were found to show up- regulation. And, a high and differential qPCR expression pattern of all the BrTIFY JAZs was also recorded against JA. Additionally, BrTIFY JAZs were tested against salt, drought, Fusarium, ABA and SA treatments and a considerable number of genes were found to be induced. The extensive annotation and transcriptome profiling reported in this study will be useful for understanding the involvement of TIFY genes in stress resistance and different developmental functions, which ultimately provides the basis for functional characterization and exploitation of the candidate genes for genetic engineering of B. rapa.

Citrus canker caused by Xanthomonas citri pv. citri is one of economically important diseases in the citrus industry. The devastating bacterial disease results in unattractive quality and a significant reduction in fruit production. Citrus growers and industry in Korea has been struggling with the serious disease causing the prohibition of export market. Korea also became the top import market for oranges. The development of markers linked to citrus canker resistance is strongly needed. In this study, we investigated molecular markers between ‘Kiyomi’ (Citrus unshiu ｘ C. sinensis), a resistant cultivar, and Natsudaidai (C. natsudaidai), a susceptible cultivar. To develop markers, we focused on structural variation (copy number variation, CNV, and presence/absence variation, PAV). It has been well documented that CNV and PAV of defense-related genes are associated with resistant cultivars. Using a read depth approach following next-generation sequencing, we performed genome-wide analysis of CNV and PAV in two varieties. As a result, 633 genes showing at least two times difference between the mapping reads from two varieties and 61 genes showing presence of the mapping reads in only either one of them were screened. Visual inspection using the Integrative Genomics Viewer (IGV) was performed and experimental validation is being investigated. Interestingly, one of PAV candidates showed polymorphism in ‘Kiyomi’ and ‘Natsudaidai’ as well as other resistant and susceptible cultivars. Our results suggest a necessity for the detection of structural variation and indicate that the candidates may be useful for molecular breeding for citrus canker resistance and understanding disease resistance mechanism.

Bacterial spot of tomato (Solanum lycopersicum L.) is caused by at least four species of Xanthomonas with multiple physiological races. In this study, we developed a mapping population for association analysis of bacterial spot resistance. For this population, six advanced breeding lines with distinct sources of resistance were first crossed in all combinations and their F1 hybrids were intercrossed. The 1,100 segregating progeny from these crosses were evaluated in the field against T1 strains. Based on this individual evaluation, we selected 5% of the most resistant and 5% of the most susceptible progeny for evaluation as plots in two subsequent replicate field trials inoculated with T1 and T3 strains. A total of 461 markers across 12 chromosomes were used for genotyping these selections. Of these markers, an optimized subset of 384 SNPs was derived from the 7,720 SNP Infinium array developed by the Solanaceae Coordinated Agricultural Project (SolCAP). For association analysis to detect known resistance loci and additional novel loci, we used the mixed models with correction for population structure, and found that accounting for kinship appeared to be sufficient. Detection of known loci was not improved by adding a correction for structure using either a Q matrix from model-based clustering or covariate matrix from Principal Component Analysis. Both single-point and haplotype analyses identified strong associations in the region of the genome known to carry Rx-3 (chromosome 5) and Rx-4/Xv3 (chromosome 11). Additional QTL associated with resistance were detected on chromosomes 1, 3, 4, 6 and 7 for T1 resistance and chromosomes 2, 4, and 6 for T3 resistance. Haplotype analysis improved our ability to trace the origin of positive alleles. These results demonstrate that both known and novel associations can be identified using complex breeding populations that have experienced directional selection.