A high-yield Korean rice cultivar cv. Boramchan and Hanmaeum, and rice cultivar for use in staple cv. Hopum were prepared and investigated for their physiological characteristics. Water content, water holding capacity, amylose content, damaged starch content, particle size, and pasting properties of the rice flours were measured. Moisture content of the Boramchan and Hanmaeum, made under wet and dry milling conditions, were as follows: wet conditions (14.79% and 13.56% respectively) and dry conditions (7.98% and 7.14% respectively). Water holding capacity of the Boramchan and Hanmaeum made by wet milling condition was 236.67% and 231.35%, respectively. Water holding capacity of the samples made by dry milling condition showed a higher score compared with other samples. The amylose content of Hopum, Boramchan, and Hanmaeum made by dry milling condition were 19.12%, 19.55% and 19.59%, respectively. Damaged starch contents of the samples made by wet milling showed a lower score. Final viscosity of Hopum, Boramchan, and Hanmaeum made by wet milling condition was 2,604, 3,052, and 2,917 cp, respectively. In this study, the results indicated that the super-yield Korean rice flour made by wet milling condition tends to show a lower water holding capacity, damaged starch contents and particle size, as compared to controls. However, a setback of the super-yield Korean rice flour was a higher score as compared to the controls, regardless of the milling conditions.

Tongil (IR667-98-1-2) rice, developed in 1972, is a high-yielding rice variety derived from a three-way cross between indica and japonica. Tongil contributed to staple food self-sufficiency of Korea, an achievement that was termed the ‘Korean Green Revolution’. In this study, we analyzed the nucleotide-level genome structure of Tongil rice and compared it to those of the parental varieties. A total of 17.3 billion Illumina Hiseq reads, 47× genome coverage, were generated from Tongil rice. Three parental accessions, two indica and one japonica types, of Tongil rice were also sequenced for approximately 30x genome coverage. A total of 2,149,991 SNPs were detected between Tongil and Nipponbare; the average SNP frequency of Tongil was 5.77 per kb. Genome composition based on the SNP data by comparing with the three parental genome sequences on sliding window of Nipponbare genome sequence revealed that 91.8% of the Tongil genome originated from the indica parents and 7.9% from the japonica parent, different from the theoretical expectation in a three-way cross, i.e., 75% indica and 25% japonica parental origins on average. Copy number of SSR motifs, ORF gene distribution throughout the whole genome, gene ontology (GO) annotation, yield-related QTLs or gene locations, and polymorphic transposon insertions were also comparatively analyzed between Tongil and parents using sequence-based tools. The results indicated that each genetic factor was transferred from parents into Tongil in proportion to the whole-genome composition. The Tongil rice is the first successful superior cultivar derived from indica × japonica hybridization in Korea. Defining of genome structure demonstrates that the Tongil genome is composed mostly of the indica genome with a small proportion of japonica genome introgression. This work was supported by a grant from the Next-Generation BioGreen 21 Program (Plant Molecular Breeding Center No. PJ008125), Rural Development Administration, Republic of Korea.

국내 쌀 품종의 아밀로오즈 함량에 따른 총 11종 쌀가루의 아밀로오즈 함량, 손상전분, 수분함량, 수분흡수지수(WAI), 수분용해지수(WSI), 입도분포 및 호화특성을 분석하였다. 국내 메성 쌀 품종 쌀가루의 아밀로오즈 함량은 9.95-21.52, 중간찰성은 11.69 및 찰성은7.09%의 아밀로오즈 함량을 나타냈으며, 유색미 메성품종은 17.06-18.36% 및 유색 찰성 품종은 7.04%의 아밀로오즈 함량을 나타내는 것으로 확인되었다. 국내 쌀품종 쌀가루의 수분함량은 7.19-13.89%를 나타내었고,수분흡수지수(WAI) 및 수분용해지수(WSI)의 경우 각각 남일 및 동진찰이 가장 높게 나타났고, 수분함량이 높은 시료의 경우 손상전분 함량이 낮은 것을 확인하였다. 국내 11품종의 쌀가루 입도 분포는 27.61- 189.67 μm를 나타내었으며 일반 메성 신동진 이 189.67 μm로 가장높은 입도를 나타내었으며, 일반메성 품종인 남일이27.61 μm로 가장 낮은 입도분포를 나타내는 것으로 확인되었다. 또한 본 연구결과 쌀가루의 수분함량이 낮은시료가 전분입도가 낮으나 손상전분 함량이 높은 것으로 확인되었으며, 일반 메성 품종의 경우 수분함량 및입도가 작은 시료는 최고 점도 및 최종점도가 높고, 유색메성품종의 경우 수분함량 및 입도가 작은 시료는 점도가 낮은 결과를 나타냈다.

The application of next generation sequencing technologies allows us to discover the high levels of DNA polymorphism throughout a genome, e.g., single nucleotide polymorphisms (SNPs), and insertions and deletions (InDels). We performed whole-genome resequencing of a Korean rice cultivar (cv. Donganbyeo) and then obtained the sequences of covered 366,042,872 bp (96.63%) with average mapped read depth of 34.17 on 382,788,128 bp of the Japanese cultivar genome (cv. Nipponbare). We characterized the polymorphisms of 173,711 SNPs, 295,334 insertions and 40,642 deletions based on the comparison of both genomes. About 11.5% and 17.8% of the annotated total SNPs were presented in the regions of 1kb upstreams and genes, respectively. The annotated InDels in gene regions were similar with 15.5% insertion (4,588) and 15.9% (5,100) deletions, but not in 1kb upstream regions with 9.0% insertion (2,662) and 14.3% deletions (5,100). In addition, the Korea rice genome sequences were mapped on individual chromosome, resulted that SNPs were shown with different frequencies from each chromosome. The InDels distributions on individual chromosomes exhibited similar pattern as compared to those of SNPs. Some gene families such as NB-ARC (NB-LRR), F-box, RLK (serine/threonine protein kinase) and Zinc-finger (RING) for SNPs occurred the similar pattern with those of Arabidopsis. These results might be useful for better understanding the genome structure and genetic diversity of the Korean rice cultivars.