Pepper is one of the most important vegetables in South Korea. It is a key ingredient in kimchi, the nation’s staple dish, and serves as the primary raw material for producing gochujang, a commonly used condiment in Korean cooking. As a result, numerous pepper varieties have been developed, including those that yield more fruit or have milder pungency. However, farmers who grow peppers tend to prefer varieties that are resistant to pests and diseases. Bacterial wilt (BW) is one of the most devastating diseases affecting peppers and is transmitted through the soil. To breed pepper varieties resistant to bacterial wilt using molecular breeding techniques, it is essential to first identify the Quantitative Trait Locus (QTL) that confers resistance to this disease. This requires conducting locus analysis with resistant cultivars. In this study, an F2 population was developed by selfing F1 hybrids, which were obtained by crossing a resistant cultivar with a susceptible cultivar, to identify QTLs associated with bacterial wilt resistance. Genotyping-by-Sequencing (GBS) analysis will be performed using the F2 population, and the results will be utilized for QTL mapping.

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.

The soybean Kunitz trypsin inhibitor (KTI) protein is responsible for the inferior nutritional quality of unheated or incompletely heated soybean meal. Ti locus controls presence or absence of Kunitz trypsin inhibitor protein. Genetic recombination or tight linkage between Ti locus and Satt228 marker that has been identified to be tightly linked to the Ti locus was detected for marker assisted selection (MAS) using two F2 populations of titi genotype in this study. Two F2 populations were developed from the cross of A29 (KTI protein present, TiTi genotype, AA genotype in Satt228 marker) x Gaechuck#1 and Gaechuck#2 (KTI protein absent, titi genotype, BB genotype in Satt228 marker). Among 31 F2 plants derived from A29 x Gaechuck#1, twenty nine F2 plants show BB genotype that indicates no recombination between Satt228 marker and Ti locus. Only 2 F2 plants show AA genotype that indicates recombination between Satt228 marker and Ti locus. Twenty eight F2 plants derived from A29 x Gaechuck#2 show BB genotype that indicates no recombination between Satt228 marker and Ti locus. Expected genetic ratio between Satt228 marker and Ti locus was 3.6 cM in F2 population.

Root-knot nematode, Meloidogyne incognita is a virulent pest of solanaceaous crops worldwide. The M. incognita resistance gene Me7 derived from Capsicum annuum CM334, is located on chromosome 9. In the present study, an F2 population derived from a cross between ECW03R and CM334 was used to locate the Me7 gene. An F2 population was inoculated using approximately 1,000 second-stage juveniles per individual plant. Phenotype screening was done 45 days after inoculation by using gall index system. The phenotype study of 503 F2 individual showed 391 resistant and 112 susceptible plants. The 3:1 phenotypic ratio confirmed that resistance phenotype is controlled by a single dominant gene. Previously reported two markers were tested to reveal the linkage of markers to phenotype. Two markers, CAPS_F4R4 and SCAR_PM6a were located at 4.3 and 2.7 cM from the resistance gene, respectively. Additional SNP markers were developed using CM334 reference genome information to narrow down the position of the gene, but no closer markers could be developed due to errors of DNA sequence assembly. The closest marker was positioned on telomere of the chromosome 9 long arm, where tens of other NB-LRR genes are clustered. NB-LRR genes are being used as candidates to identify the Me7 gene.

식용 풋찰옥수수 고품질 육종에 관련된 주요 형질들의 특성을 파악하고자 수행한 본 연구는 모계 02S6140(찰옥수수, SSww)와 부계 KSS22(단옥수수, ssWW)의 교잡(F1)에서 분리된 F2 집단에서 수량 및 식미관련 형질들의 유전적 특성을 조사하였다. 그 결과 출사일수는 모본(02S6140) 계통이 85일, 부본(KSS22) 계통이 66일로 현저한 차이가 있었지만, F1은 71일로 교배친의 평균값 75.5일보다 작아지는 방향으로 나타났다. 간장(PH)은 F1에서 159 cm, 모부의 평균값 95 cm와 비교하여 크게 나타났다. 착수고율은 F2 집단의 평균이 교배친의 평균값 44와 동일하였고 찰질이 일반질 옥수수보다 높은 것으로 나타났다. 과피두께는 F1, F2 계통들에서 71 μm과 74 μm로 나타나 모부의 83.5 μm 평균보다 얇아지는 방향으로 나타났다. 아밀로스함량은 입질별로 매우 유의하게 차이가 있어 일반질이 평균 14.0%로 가장 높았으며 당질은 7.4%, 찰질은 5.0%의 값을 보였으며, 아밀로스함량에 대한 F1의 잡종강세는 비교적 높은 116.1의 값을 보였다. 유전자형 suwx는 이중열성돌연변이로 표현형은 sugary로 나타났다.

In this study, we were conducted the construction of the framework map using SSR markers in the F2 population derived from a cross between waxy corn inbred line (02S6140) and sweet corn inbred line (KSS22), and also identifying of QTLs associated with eating quality traits by employing genetic linkage map of F2:3 population. The linkage map was constructed using 295 SSR markers on the 158 F2 individuals derived from a cross of 02S6140 and KSS22. The map comprised a total genomic length of 2,626.5cM in ten linkage groups and an average distance between markers of 8.9cM. Chi-square test revealed that 254 markers (86.1%) associating with all ten chromosomes exhibited a segregation of 1:2:1 Mendelian ratio. A total of 10 QTLs each for pericarp thickness (PER), amylose content (AMY), dextrose content (DEX), and sucrose content (SUC) were detected in the 158 F2 families. The number of QTL per each trait was ranged from 2 to 4, and also phenotypic variance was ranged from 4.26 to 30.71%. For PER, 4 QTLs were found to be controlled by four genomic regions at locations chromosomes 4, 5, 8, and 9 contributing 10.43, 6.71, 6.74, and 7.79% of phenotypic variance, respectively. While 2 QTLs for AMY, DEX, SUC traits, were found to be controlled by two genomic regions at locations chromosomes 4, 6, 8, and 9 contributing between 4.26 and 30.71% of phenotypic variance, respectively. Among them, 4 QTLs, such as qAMY4 (10.43%), qAMY9 (19.33%), qDEX4 (21.31%), and qSUC4 (30.71%), may be considered as a major QTLs, while the remaining six QTLs might be regarded as minor QTLs. In our study, qAMY9 for amylase content was detected on chromosome 9 in marker intervals phi027-umc1634, which was the same locus as encoding wx1 gene. Thus qAMY9 may be thought very useful molecular marker for selecting amylase content trait. The other QTLs may be thought very useful molecular marker for eating quality traits. The resulting genetic map will be useful in dissection of quantitative traits and the identification of superior QTLs from the waxy hybrid corn, and also this study may provide valuable information for the further identification and characterization of genes responsible for eating quality-related traits in waxy corn and sweet corn.