• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.23-23
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• 2022

Rapeseed (Brassica napus L.) is one of the most valuable oilseed crop in the world. It is widely used in various industries, such as food, animal feed, energy and chemical industries. In order to improve the industrial requirements for rapeseed, useful agronomic characteristics (higher yields and disease resistance etc.) and modified oil traits (fatty acid composition and fat content) are important in rapeseed. However, Korea has limiting genetic resources of novel traits in rapeseed. In this research, novel rapeseed mutant genotypes by mutation breeding was developed. The mutant lines were generated by the treatment of the seeds of the original cultivar 'Tamra' with 700 Gy of gamma-ray (⁶⁰Co). Mutants showing varied in flowering time, crude fat content, seed yield and fatty acid content that exhibited stable inheritance of the mutated characteristics from M₅ to M₇ generations were selected. We investigated genetic variation using SNPs identified from GBS analysis in rapeseed mutant lines derived from the gamma-ray, and interactions between the major agronomic and the oil traits. Significantly associated SNP loci were explored along with candidate genes using SNPs obtained by GBS analysis. As a results of association mapping, a total of 322 SNPs were significantly associated with agronomic traits (155 SNPs) and oil traits (167 SNPs). A total of 70 genes were annotated from agronomic characteristics SNPs; among them 7 genes significantly enriched in developmental process, and a total of 70 genes were annotated from crude fat content and fatty acid compositions SNPs; among them, 11genes were significantly enriched in biosynthetic process. These results could be used for the selection of rapeseed cultivar with enhanced qualities and potential economic benefits.

• Journal of Crop Science and Biotechnology
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• v.11 no.4
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• pp.263-268
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• 2008

Bacterial leaf pustule (BLP) caused by Xanthomonas axonopodis pv. glycines is a serious disease to make pustule and chlorotic haloes in soybean [Glycine max (L). Merr.]. While inheritance mode and map positions of the BLP resistance gene, rxp are known, no sequence information of the gene was reported. In this study, we made five near isogenic lines (NILs) from separate backcrosses (BCs) of BLP-susceptible Hwangkeumkong $\times$ BLP-resistant SS2-2 (HS) and BLP-susceptible Taekwangkong$\times$ SS2-2 (TS) through foreground and background selection based on the four-stage selection strategy. First, 15 BC individuals were selected through foreground selection using the simple sequence repeat (SSR) markers Satt486 and Satt372 flanking the rxp gene. Among them, 11 BC plants showed the BLP-resistant response. The HS and TS lines chosen in foreground selection were again screened by background selection using 118 and 90 SSR markers across all chromosomes, respectively. Eventually, five individuals showing greater than 90% recurrent parent genome content were selected in both HS and TS lines. These NILs will be a unique biological material to characterize the rxp gene.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.142-142
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• 2017

Wheat (Triticum asetivum L.) is one of the major grain crops worldwide. The reduced productivity ascribed by adverse environment is increasing the risk of food security. Wheat cultivars have been actively released by public side since 1960s in Korea. Each variety has been developed for superior regional adaptation, pest resistance and mostly high yield. Heat stress tolerance is one of the major parameters that threaten wheat production in Korea. Heat stress during grain filling period has been conceived as critical level and directly influences on wheat production. We evaluated 11 common wheat cultivars ("Baegjoong", "Dajung", "Goso", "Hanbaek", "Jokyoung", "Joeun", "Jopum", "Keumgang", "Olgeuru", "Sinmichal", "Uri") that were exposed to abnormally high temperature during the grain filling period. Each plant was grown well in a pot containing "Sunshine #4" soil in controlled phytotron facility set on $20^{\circ}C$ and 16 h photoperiod. At 9 day-after-anthesis (DAA9), plants were subjected to a gradual increase in temperature from $20^{\circ}C$ to $33^{\circ}C$ and maintained constantly at $33^{\circ}C$ for 5 days. After the treatment, plants were subjected to gradual decrease to normal temperature ($20^{\circ}C$) and continue to grow till harvest. Seeds were harvested from each tiller/plant. Total chlorophyll contents decrease level as well as grain parameters were measured to evaluate varietal tolerance to heat stress. We also divide each spike into five regions and evaluate grain characteristics among the regions in each spike. The obtained results allow us to classify cultivars for heat stress tolerance. The pedigree information showed that typical wheat lines provide either tolerance or susceptible trait to their off-springs, which enable breeders to develop heat stress tolerance wheat by appropriate parental choice.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.278-284
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• 1990

We have demonstrated expression of bacterial genes transferred into cells of Populus nigra ${\times}$ P. maximowiczii by A. tumefaciens strain 6044 (pGA 472). We determined the optimum concentration of kanamycin sulfate for effective selection of punctured leaf transformed using Agrobacterium binary vector pGA 472 containing a neomycine phosphotransferase gene (NPT-II) which confers kanamycin resistance. The combination of cefotaxime (200mg/l) and carbenicillin (300mg/l) showed good performance of discarding Agrobacterium from inoculated punctured leaf. A relatively low concentration (10mg/l) of kanamycin sulfate inhibited callus and shoots induction from punctured leaf. Number of shoots regenerated from co-cultured punctured leaf was 3.0 on MS basal medium supplemented with 10 mg/l kanamycin sulfate, while that of not co-cultured punctured leaf was none. The regeneration rate was 10% from the punctured leaf co-cultured on MS medium with 10 mg/l kanamycin. Regenerated shoots are developing from micropropagation for Southern blot analysis and inheritance of the kanamycin resistance trait (NPT-II).

• Horticultural Science & Technology
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• v.18 no.3
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• pp.342-347
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• 2000

The objectives of this study were to investigate the genetic and phenotypic features of male sterile transformants by pollen-specific expression of diphtheria toxin gene and to find out inheritance patterns of transgene to the next generation. When backcrossed (BC) progenies were tested for expression of kanamycin resistance ($Km^R$), 9 lines out of 13 lines, except 4 lines ($BC_{1}5-13,\;BC_{1}5-23,\;BC_{1}5-28,\;BC_{1}5-32$), showed the ratio of $Km^R$ to kanamycin sensitive ($Km^S$), from 1:30 to all $Km^S$. As a result, they were much lower than Mendelian segregation of a dominant gene. To determine whether male sterility is a heritable and stable trait, 5 male sterile plants ($BC_{1}5-13,\;BC_{1}5-14,\;BC_{1}5-23,\;BC_{1}5-32,\;BC_{1}5-33$ lines) which had different transgene copy numbers were backcrossed as female parents with pollens from wild type. To confirm the existence of the DTx-A gene in the genome of the progenies, PCR was conducted using specific primers of the DTx-A coding region. A PCR band of 428 bp was obtained from each generation, which is the predicted size of the DTx-A gene fragment. Trangenes were inherited to the next $BC_4T_0$ progenies and showed male sterility, however, based on the copy numbers of DTx-A gene male sterile plants did not show predicted ratio. When male sterile plants were backcrossed with fertile plants, fruit capsule sizes and seed settings were relatively reduced from those of selfing wild type plants. The fruit sizes and seed settings were reduced in proportion to the increase in the copy number of DTx-A gene.

• Journal of Life Science
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• v.30 no.9
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• pp.798-803
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• 2020

Late in the 1960s, South Korea established cultivation technology and began breeding new "Tongil" type rice cultivars by crossing indica and japonica. To date, this cultivation technique has been used to produce a wide variety of cultivars to meet consumer preferences and adapt to extreme weather conditions. Once major genetic traits are no longer segregated through advanced generations, varieties obtained from a cross between different crops may become a new variety. In this study, we confirmed the agronomic traits of F₄, F₅, and F₆ by advanced generation a population in which drought tolerance and brown planthopper (BPH) resistance were crossed. HV23, Ilmi/HV23, and Drimi2ho/HV23 were used. HV23 was drought-tolerant, and Drimi2ho was resistant to BPH. As a result, it was possible to consider that the agronomic traits were fixed because none of them showed a significant difference from the others. While it takes more than 10 years for the pedigree method of breeding, this study confirmed that the agronomic traits were fixed in 4-6 years. In the future, we will investigate the homology of the CaMsrB2 gene and the Bph1 gene, to confirm that both genes are closely related to each other, and analyze the stable inheritance of the introduced gene for multiple successive generations.