DPPH(l, 1-diphenyl-2-picrylhydrazyl) free radical scavenging activity assay was used to analyze antioxidant activities in 249 Korean rice landraces. Especially, red rice varieties were 13 accessions, showed very strong antioxidant activities more than 95%. Brown rice varieties were 236 accessions, among them G307 showed the highest antioxidant activity of 68%. Most of brown rice varieties showed higher activities than Chucheongbyeo as check variety. 101 accessions were distributed range of 21 - 30% and 71 accessions were distributed range of 31 -40%.

This study was conducted to characterize the amylose and protein contents of 4,948 rice landrace germplasm using the NIRS model developed in the previous study. The average amylose content of the germplasm was 20.39% and ranged between 3.97 and 37.13%. The amylose contents in the standard rice were 4.99, 18.63 and 20.55% in Sinseonchal, Chucheong and Goami, respectively. The average protein content was 8.17% and ranged from 5.20 to 17.45%. Protein contents in Sinseonchal, Chucheong and Goami were 6.824, 6.869 and 7.839%, respectively. A total of 62% germplasm were distributed between 20.06% and 27.02% in amylose content. Germplasm of 81.60% represented protein content of 6.78-9.75%. The distinguishable ranges of amylose contents according to origin were 16.58-20.06% in Korea, 20.06-23.25% in Japan, 23.25-27.02% in North Korea, and 27.02-37.13% in China. In the protein content, approximately 30% of Chinese resources ranged from 9.75 to 17.45%, whereas less than 10% were detected in other origin accessions. Fifty resources were selected with low and high amylose ranging from 3.97-6.66% and 30.41-37.13%, respectively. Similarly, fifty resources were selected with low and high protein ranging from 5.20-6.09% and 13.21-17.45%, respectively. Landraces with higher protein could be adapted to practical utilization of food sources.

In order to assess the genetic diversity, phylogenetic relationships and population structure of Korean rice landraces, 76 accessions were estimated using agronomical traits and SSR markers. Among 11 agronomical traits, amylose content (AC) was the trait with the largest variance with values ranged from 4.9 to 28.39 %, while grain length (GL) was the lowest variance ranged from 4.4 to 5.9 cm. In the result of PCA, the first PC with Eigen value of 217.5 explained 60.3% of the total variance. Culm length (CL) was the variable with the largest positive loadings. Growth period (GP) was the positive variances, while AC was the negative variance. The second PC with Eigen value of 80.6 explained an additional 22.4% of the total variance. Growth period (GP) was variable with highest positive loading. Amylose content (AC) was variable with high positive, while CL was the negative variance. The 49 SSR markers produced a total of 473 alleles with an average of 9.6 alleles. The polymorphism information content (PIC) was in the range 0.11 to 0.93. The observed heterozygosity ranged from 0.12 to 0.39, with an average of 0.61. 76 rice accessions showed two subpoplations and three groups based on SSR markers. Group I and Gropu II appertained Pop-2 and Pop-1 subpopulation, respectively. They showed similar agronomical traits. Group III consisted 7 rice accessions predominantly appertained to Pop-1. These results provide insight into the characters of Korean rice landraces and help to improve our knowledge of rice breeding

Banaue Rice Terraces in the Philippines has been a rich source of genetic diversity of untapped rice landraces in the mountainous region of Cordillera. Although some may have been included into modern breeding programs, significant indica-japonica differentiation among landraces cultivated in the region is not well known. Thus, Cordillera landraces differentiation across different altitude gradient (458 m to 1830 m) will provide great opportunities for improvement on rice genetics. We analyzed the genetic variation among 166 accessions collected in 17 towns in 6 provinces across different altitudes using Subspecies Specific Sequence Tagged Site (SS-STS) and Insertion-Deletion (InDel) markers. Subspecies Prototype Index (SPI) degree of each landrace was used to calculate the genomic inclination of each variety towards subspecies. The 50 molecular markers (24 SS-STS and 26 InDel) that assayed variation in 166 accessions revealed 116 alleles. Gene diversity ranged from 0.04 (R3M23) to 0.50 (S04058) with an average of 0.40. Polymorphism information content (PIC) ranged from 0.04 (R3M23) to 0.37 (S12030, S07047, R10M40, S10001, S04058 and S09040B) with an average of 0.31. Using the control varieties to assign groups, the larger group of 114 Cordillera landraces corresponds to 71% japonica type while the smaller group of 42 corresponds to 26% indica and 3% intermediates. A total of 7 (4%) indica and 9 (6%) japonica type accessions were found above 1500 m. Results of this study suggested that majority of japonica type rice landraces were grown in high altitudes of Banaue Rice Terraces and nearby provinces, and interestingly, indica type rice landraces were cultivated in areas at much higher altitudes (>1500 m) than those categorized by the traditional methods.