앙골라에 잘 적응하는 다수성 옥수수 품종 육성을 위한 기초지식을 얻기 위해 앙골라 옥수수 재래종 자원 89점을 대상으로 24개의 SSR 마커를 이용하여 유전적 다양성 분석을 실시한 결과는 다음과 같다. 총 254개의 allele가 탐지되었고 마커당 평균 allele 수는 10.6이었다. 마커의 PIC 값은 0.23 ~ 0.92 범위에 있었으며 평균값이 0.64이었다. 앙골라 옥수수 재래종 유전자원들은 매우 높은 유전적 다양성을 보여 계통간 비유사성(dissimilarity) 평균값이 0.643 이었고, 뚜렷하게 소수의 그룹들로 구분되지 않았다. 이러한 고도의 다양성을 가진 재래종 옥수수 유전자원을 이용하여 앙골라에 잘 적응하는 다양한 다수성 품종을 육성할 수 있을 것으로 기대된다.

본 논문에서는 수중운동체 중 하나인 잠수함의 코닝타워(Conning tower) 위치 및 제어판 형태에 따라 4가지 타입별로 나누어 회 전팔 시험(Rotating arm test)을 실시하였다. 또한 본 RA 시험을 통하여 유체력 미계수를 추정하였으며 수평면 운동에 대한 동적 안정성 (Dynamic stability)을 평가하였다. 특히, 자유수면의 영향으로부터 자유로운 심도비(Depth ratio) 6.0에서 힘과 모멘트를 측정한 후, 다중회귀 분석을 이용하여 유체력 미계수를 추정하였다. 최종적으로 선형유체력 미계수를 이용한 수평면 동적 안정성 지수를 산정함으로써 잠수함 타 입별 특성이 동적 안정성에 미치는 영향을 분석하였다.

Brown planthopper (BPH) is a phloem sap-sucking insect pest of rice, which causes severe yield loss annually. Gayabyeo, a Tongil type rice variety, is known to have broad spectrum resistance to BPH. Before, it was estimated that Gayabyeo has at least two BPH resistance genes. We started a research for mapping resistance genes of Gayabyeo. We did a cross between Taebaekbyeo, a BPH susceptible Tongil type rice variety, and Gayabyeo, We grew F1 plants in winter season of 2014-2015, and planted F2 population in this year. About 100 DNA markers (SSR and InDel markers) showing polymorphism between Gayabyeo and Tabaekbyeo were selected. In addition, we are going to do resequencing Gayabyeo and Taebaekbyeo using Illumina Hiseq2000 to find much more DNA polymorphisms between the two varieties and develop new markers for mapping. The BPH response data will be acquired using F3 plants from the cross between Gayabyeo and Taebaekbyeo next year. In a while, crosses between Gayabyeo and high quality japonica rice varieties are being carried out to introduce BPH resistance genes of Gayabyeo into japonica high quality rice varieties. We expect to develop new DNA markers for BPH resistance genes of Gayabyeo through mapping and produce several japonica high quality rice lines harboring those genes at the end of this project.

Rice is one of the most important cereal crops in the world and a model plant for functional genomics of monocotyledon. Recently, rice crop loss is estimated to be approximately 30% of the total yield due to herbivorous pests, mainly insects. Cry1Ac toxin is a protein produced by the bacterium Bacillus thuringiensis and has insecticidal properties. CryBP1 toxin also is an insecticidal protein produced by the bacterium Bacillus popilliae. These two toxic genes derived bacteria, which were inserted into a binary vector, have been introduced into rice plants by Agrobacterium tumefaciens mediated transformation in order to enhance resistance to insects. Here, we utilized anthers to regenerate transgenic rice plants when it has been plated on the callus induction media as a callus-inducing material. Anther culture has a benefit in terms of being apt to produce doubled haploids in short term in plants breeding compared to seed culture. However, anther culture method in generating transgenic rice still has low productivity of plant regeneration in some genotypes of Japonica rice. Therefore, we examined the efficiency of callus induction and transformation with three different cultivars of Japonica rice, Haiami, Ungwang and Dongjin. In this study, our results showed that Haiami is the best genotype among three cultivars of Japonica rice as callus inducing material in anther culture to produce transgenic rice plants conferring resistance to insects.

Internode elongation is an important agronomic trait in rice that is associated with lodging, yield, and flooding adaptation. We identified a novel rice mutant line showing shortened uppermost internode among the rice Ac/Ds insertional mutant population and named it shortened uppermost internode 4 (sui4). The phenotypes of F1 plants and F2 plants from the cross of sui4 with its original variety, Dongjin, indicated that the SUI4 gene shows incomplete dominance or semidominance. Because the Ds genotypes did not co-segregate with the sui4 phenotypes, we performed mapping of this gene with 273 F2 plants from a cross between sui4 and Milyang23. Primary mapping revealed that the SUI4 locus was located between the S07012 and S07015 markers on rice chromosome 7. Further fine mapping narrowed down the location of SUI4 to the 1.1-Mbp interval of RM1253-S07015. Using re-sequencing data of this mutant along with its original variety, Dongjin, and five other varieties, we found six sui4 specific SNPs occurred within the genic region of five genes in the fine-mapped interval. Among them, one SNP is in exon, while the other five SNPs are in intron. This SNP in exon occurred in the miR172 binding site of a gene encoding AP2 domain transcription factor, which seems to interrupt suppression of this gene activity by miR172. We isolated the genomic region of this gene from sui4 and transformed the wild type variety, Dongjin. The transgenic plants showed remarkably shortened internodes, which indicates that this AP2 domain transcription factor gene is the SUI4 gene.

Drought and salinity are the major abiotic stresses which are being continued to hamper the ecosystem and agriculture of the affected region. Plant species have adaptations to enhance their ability to tolerate stresses through physiological adjustment. Therefore, substantial amount of research are ongoing to provide insights about those mechanisms which enlighten the stress tolerance in plant. In this study, several rice cultivars were collected from the different parts of the world and ion accumulation experiments were conducted to select the best stress tolerant cultivar in drought and salt stress environment. For stress treatment, five rice cultivars were subjected to salt (200 mM NaCl) and drought (200 mM Mannitol) for 72h. Later Na+, Ca++, K+ concentrations in shoot and root samples were examined at different time interval. In both drought and salt stress, rice cultivar C201 (collected for uzbekistan) showed the lowest levels of Na+ ion and Na+: K+ ratio compared to other cultivars. It was significant parallel observation with pokkali (known salt tolerant cultivar). In this preliminary study, it was observed the C201 had more stress tolerant in terms of ion accumulation; however detail physiological studies are required to strengthen the idea regarding the best stress tolerant physiotype.