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.

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.

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.