Backcrossing is a plant breeding method most commonly used to incorporate one or a few genes into an adapted or elite variety. To facilitate MAB (marker-assisted backcrossing) in a practice breeding program, we developed a SNP database and a program for providing selected markers for background selection from genome-wide SNPs of seven tomato accessions downloaded from NCBI-SRA. We identified 425,935 SNPs among 21 parental combinations with data from seven transcriptomes and developed a SNP database. To select the optimized number of markers for background selection, we divided 12 chromosomes according to physical length and genetic length. Initially, each chromosome was equally divided into five blocks according to physical length, and three SNPs were positioned per block. Additionally, we applied the genetic distance calculated from the recombination rate because the frequency of recombination can vary greatly among chromosomal regions. When considering genetic distance, each chromosome was divided into fifteen blocks unequally and one marker composed of EXPEN-2000 was positioned per block. The program for background selection was designed to be simple and easy to use, and it is available at http://tgsol.seeders.co.kr/ index.php/tg/mab. When the user selects the parental combination, the program provides selected markers with primer information. The value of this program for tomato breeding will further increase if more accession numbers are added to the database.

고추 탄저병은 국내에서 아주 피해가 심한 병 중의 하나로 본 연구팀은 십수 년 동안 탄저병 저항성에 대해 유전분석을 수행하는 동시에 저항성 품종 육성에 노력을 기울여 왔다. 이전에 사용하였던 탄저병 저항성 소재는 Capsicum baccatum 종의 PBC81 accession이었는데, 이와 가장 교잡화합성이 높았던 C. annuum 종의 SP21 계통을 모친으로 사용하여 종간 교잡을 수행하였고, 이에 대한 BC1F1과 BC1F2 분리집단에서 QTL mapping을 수행하여 두 가지의 탄저병(Colletotrichum acutatum과 C. capsici)에 대한 각각의 저항성 주동 QTL을 탐색함과 동시에 연관된 분자표지를 개발하였다. 본 연구에서는 탄저병 저항성 소재로 PBC81이 아닌 PI594137과 AR을 사용하여 NGS re-sequencing을 수행한 후 대량의 SNP를 탐색하고자 하였다. PI594137은 C. baccatum 종에 속하며, PBC81보다 좀 더 broad spectrum resistance를 보인다. AR은 AVRDC에서 분양 받은 재료인데, C. chinense Jacq. PBC932의 열성 저항성을 C. annuum에 도입한 계통이다. 탄저병 저항성 QTL mapping은 Golden aji(C. baccatum, 탄저병 이병성)와 PI594137의 F2 분리집단과 SP211(C. annuum, 탄저병 이병성)과 AR의 F2 분리집단에서 수행할 계획이어서 각각의 양친 사이(Golden aji vs. PI594137과 SP211 vs. AR)에서 SNP를 탐색하였다. NGS re-sequencing을 통해 읽혀진 염기서열 총 길이는 PI594137이 40.5Gbp, Golden aji가 12.1Gbp, AR이 12.8Gbp, SP211이 11.5Gbp였다. 이 염기서열을 사용하여 생물정보학적 분석((주)씨더스에 의뢰)을 수행하였는데, PI594137과 Golden aji 사이에서 333,816개, AR과 SP211 사이에서 1,218,595개의 SNP를 최종적으로 탐색할 수 있었다. 탐색된 SNP는 탄저병 저항성 QTL mapping 분석에 유용하게 사용될 수 있을 것이다.

Recently whole genome SNP genotyping has been used to do association analysis and to map a gene of interest. Here we report application of bulked segregant analysis(BSA) using Infinium HD assay with ‘BARC Bean6K_3’, a SNP genotyping beadchip containing 5,399 SNPs for common bean to locate a target gene. We used BSA using Infinium HD assay was performed to find the candidate region of a single dominant rust resistant gene in PI310762, a common bean cultivar. And SSR markers were identified and mapped on the candidate region using F2 population derived from the cross of susceptible Pinto114 x resistant PI310762. BSA revealed the candidate region of the resistant gene is on chromosome 4 where we developed nine SSR markers. Three SSR markers (beanssr1170, beanssr1168, and beanssr1167) of them appeared closely linked to the resistant gene which is located between beanssr1167 at 0.1cM and beanssr1170 at 0.5cM on chromosome 4. This study showed BSA using high-throughput whole genome SNP genotyping is a very fast and efficient method to locate a gene of interest on chromosome.

Genome-wide association study (GWAS) is a very powerful method to identify the natural allelic variation present in crop plants causing variation to economically important traits. The recent advances in high throughput genotyping and sequencing technology supplemented greatly to GWAS. Taking this advantage, we selected a total of 382 Chinese cabbage inbred lines for GWAS study. The selected inbred lines are being sequenced using next generation sequencing technology to develop genome wide gene specific single nucleotide polymorphism markers. The morphological and quality traits data were taken from field grown inbred lines. The phenotype and genotype association study will be done with more environmental grown data’s and developed SNP. At the end of this project, gene specific SNP markers will be developed for Chinese cabbage breeding for morphological and quality traits.

Clubroot, caused by a soil borne fungus Plasmodiophora brassicae Woronin, is a common disease of cabbages and other plants belonging to the genus Brassica, which is the most extensively cultivated vegetable crops worldwide. This present study was to evaluate the utilization possibility of SNP primers, which we designated as molecular markers linked to disease resistance based on B. rapa genome, it may be possible to apply them to B. oleracea, and to survey SNP marker related to clubroot resistance of cabbages. In total, 425 SNP markers can be applied to B. oleracea were selected from 8,000 SNP markers based on B. rapa genome linked to disease resistance. New 123 SNP markers of them were designed to be analysed to High Resolution Melt (HRM), and tested for clubroot resistance using 6 cabbage varieties, including 3 clubroot resistances (YR Chunrok, YR Dongjanggun, and Grandmart Cabbage) and 3 susceptibilities (Chungam-45, Bogam-1, and Junggam-21). Of them, 118 SNP primers amplified cabbage genomic DNA using HRM analysis, suggesting that it is possible to apply SNP markers based on B. rapa genome to B. oleracea. A total of 4 candidate SNP markers related to clubroot resistance were detected at 80.2℃ of melt temperature in BRS6, 79.2℃ in BRS18, 82.2℃ in BRS79, and at 84.4℃ in BRS114, respectively. These results provide valuable information that can be used for the utilization of the genus Brassica genome study and breeding for clubroot resistance in cabbages.

Allele mining in starch synthesis-related genes (SSRGs) has facilitated the discovery of desired natural sequence variations for eating quality in rice. This study investigated the sequence variations from 10 SSRGs, and further evaluated their relationship with the amylose content (AC) and rapid viscosity analysis profiles in a global collection of rice accessions by association mapping (AM). In total, 83 sequence variations were found in 10 sequenced amplicons, including 73 single nucleotide polymorphisms (SNPs), eight insertion-deletions (InDels) and two polymorphic simple sequence repeats (SSRs). Four subpopulations were identified by population structure analysis based on 170 genome-wide SSR genotypes. AM revealed 11 significant associations between three phenotypic indices and three sequence variations. One SNP with a g/c transversion at the 63rd nucleotide downstream of the OsBEIIb gene termination codon on rice chromosome 2 was significantly associated with multiple trait indices in both the general linear and mixed linear models (GLM and MLM), including the final viscosity (p < 0.001, R2 = 23.87%) in both 2009 and 2010, and AC (p < 0.01, R2 = 11.25%) and trough viscosity (p < 0.01, R2 = 20.43) in 2010. This study provides a new perspective of allele mining for breeding strategies based on marker-assisted selection.

배추과 작물에 속하는 양배추(Brassica oleracea var. capitata)는 해외 시장에서 활발히 거래 되는 작물 중 하나로 고부가가치 수출용 작물로 육성하기에 적합한 경쟁력을 가지고 있다. 특히 중국, 인도, 동남아시아 국가들은 육종기술이 초기수준이고 종자수요량의 대부분을 수입에 의존하고 있으며 점점 내병성, 내서성 등의 내재해성과 고순도, 고품질의 형질을 갖춘 품종 욕구가 더해가고 있다. 이에 따라 우수한 품종이 해외 시장에서 보다 확대되기 위해서는 내병성과 같은 특징뿐만 아니라 순도 또한 매우 중요한 확인사항 중 하나이다. 현재 자가불화합성을 이용한 육성기술 보다는 품종 복제가 불가능하고 균일성이 100%에 이를 수 있는 세포질웅성불임성을 이용한 육성으로 그 방향이 전환되고 있는 실정이다. 그러므로 본 연구는 순도검정용 분자표지를 개발하여 일대 잡종종자의 순도를 검정하여, 최종적으로 F1의 상품가치를 감소시키는 자식체를 검정함으로써 고순도의 종자를 공급하고자 하며, 수출경쟁력이 강화되는데 그 목적을 두고 있다. 분자표지 개발 방법으로 NCBI에서 양배추의 EST 염기서열 정보로부터 30개의 SNP primer 조합이 200bp이 되도록 고안하였다. 개발된 SNP marker는 real-time PCR를 기반으로 한 HRM분석법을 이용하여 유전분석을 실시하였다. 본 실험에서는 아시아종묘의 양배추 주력 품종인 CT12, CT44, CT10, CT55, 대박나 총 5 품종에 대해 개발된 순도검정용 marker를 적용하였다. 그 결과 5 품종 모두 (CT12, CT44, CT10, CT55, 대박나)에서 양친과 F1을 구분할 수 있는 co-dominant형태의 marker를 각각 1개 이상 개발하였다. 개발된 marker를 이용하여 5품종의 순도를 검정한 결과 세포질웅성불임성을 이용하여 채종된 종자의 순도율은 100%로 확인되었다. 개발된 양배추 순도검정용 marker를 이용한 검정은 고순도의 종자공급을 할 수 있으며 고품질의 F1 품종을 생산하는데 활용하여 양배추 종자 시장의 수출증대와 농가소득증대에 기여할 것이다. 더 나아가 유연관계가 가까운 배추과 작물에도 적용할 수 있는 순도검정 marker로 매우 유용하게 활용할 수 있을 것이라 기대된다.

The purpose of this study was to identify the variant of Platanus occidentalis, whose bark looks white, also can be classified as P. occidentalis and to examine its genetic difference from the general P. occidentalis. For the variant identification of P. occidentalis, SNP and ISSR analysis were used in this study. Thirteen samples of P. occidentalis white variant were collected in Cheongju and 24 samples of normal P. occidentalis obtained in Cheongju, Pyongtaek, Ansan, Suwon, Osan and Jincheon area. ITS 1 and ITS 2 sequences of white variants were identical with those of P. occidentalis. We could not find any sequence difference between normal and white P. occidentalis. So we concluded that the white variant belongs to normal P. occidentalis even their bark is white and peeled easily. By ISSR test, 98 amplicons were acquired using 10 primers. P. occidentalis and white P. occidentalis showed different band patterns from the UBC #834. According to the result of Nei (1979)'s genetic distance analysis, the members of white P. occidentalis were grouped more tightly than the members of normal P. occidentalis. The UPGMA dendrogram shows that the variant and P. occidentalis divided widely into two groups. These results show that the phenotype of P. occidentalis white variant is caused by genetic factors rather than by environmental factors.

The objective of this study was to determine the genetic diversities of major rice blast resistance genes among 84 accessions of aromatic rice germplasm. Eighty four accessions were characterized by a dominant 11 set of PCR-based SNP and CAPS marker, which showed the broad spectrum resistance and closest linkage to seven major rice blast resistance (R) genes, Pia, Pib, Pii, Pi5 (Pi3), Pita (Pita-2), and Pi9 (t). The allele specific PCR markers assay genotype of SCAR and STS markers was applied to estimate the presence or absence of PCR amplicons detected with a pair of PCR markers. One indica accession, Basmati (IT211194), showed the positive amplicons of five major rice blast resistance genes, Pia, Pi5 (Pi3), Pib, Pi-ta (Pi-ta2), and Pik-5 (Pish). Among 48 accessions of the PCR amplicons detected with yca72 marker, only five accessions were identified to Pia gene on chromosome 11. The Pib gene was estimated with the NSb marker and was detected in 65 of 84 accessions. This study showed that nine of 84 accessions contained the Pii gene and owned Pi5 (Pi3) in 42 of 84 accessions by JJ817 and JJ113-T markers, which is coclosest with Pii on chromosome 9. Only six accessions were detected two alleles of the Pita or Pita-2 genes. Three of accessions were identified as the Pi9 (t) gene locus.

멜론과 참외의 국내 소비 시장이 확대됨에 따라 다양한 F1 품종이 개발되고 있다. 멜론과 참외의 F1 품종의 순도를 검정하기 위해 포장재배 등의 순도검정법이 이용되고 있으나 시간과 노력이 매우 많이 소요되기 때문에 분자마커를 이용한 순도검정법의 개발이 필요하다. 본 연구에서는 멜론의 EST 염기정보로부터 30개의 SNP 프라이머 조합을 고안하여 멜론과 참외의 순도 검정을 위한 HRM분석방법을 개발하였다. 멜론 두 품종과 참외 한 품종의 양친 사이에 HR