Table 2.
Classification of rice accessions on the basis of polymorphism of DNA markers
| Cultivated ecosystems | Variety type | Regions of varieties bred | No. of accessions (%) | ||
|---|---|---|---|---|---|
|
| |||||
| Cluster group | Sum | ||||
|
| |||||
| I | II | ||||
| Irrigated lowland | Landrace | Kanto | 1 | 0 | 1 |
| Hokuriku | 1 | 0 | 1 | ||
| Tokai | 1 | 0 | 1 | ||
| Chugoku/Shikoku | 2 | 1 | 3 | ||
| Kyushu | 0 | 2 | 2 | ||
| Others | 0 | 2 | 2 | ||
|
| |||||
| Sum | 5 (1.5) | 5 (1.5) | 10 (3.1) | ||
|
| |||||
| Improved | Hokkaido | 24 | 0 | 24 | |
| Tohoku | 33 | 0 | 33 | ||
| Kanto | 17 | 3 | 20 | ||
| Hokuriku | 32 | 2 | 34 | ||
| Tokai | 40 | 1 | 41 | ||
| Kinki | 19 | 0 | 19 | ||
| Chugoku/Shikoku | 16 | 0 | 16 | ||
| Kyushu | 32 | 1 | 33 | ||
| Others | 1 | 0 | 1 | ||
|
| |||||
| Sum | 214 (66.0) | 7 (2.2) | 221 (68.2) | ||
|
| |||||
| Total | 219 (67.6) | 12 (3.7) | 231 (71.3) | ||
|
| |||||
| Upland | Landrace | Tohoku | 4 | 3 | 7 |
| Kanto | 2 | 17 | 19 | ||
| Tokai | 1 | 4 | 5 | ||
| Kinki | 1 | 1 | 2 | ||
| Chugoku/Shikoku | 2 | 1 | 3 | ||
| Kyushu | 2 | 5 | 7 | ||
| Others | 2 | 7 | 9 | ||
|
| |||||
| Sum | 14 (4.3) | 38 (11..7) | 52 (16.0) | ||
|
| |||||
| Improved | Hokkaido | 0 | 1 | 1 | |
| Tohoku | 0 | 3 | 3 | ||
| Kanto | 0 | 7 | 7 | ||
| Tokai | 1 | 0 | 1 | ||
| Kinki | 1 | 3 | 4 | ||
| Kyushu | 0 | 1 | 1 | ||
|
| |||||
| Sum | 2 (0.6) | 15 (4.6) | 17 (5.2) | ||
|
| |||||
| Total | 16 (4.9) | 53 (16.4) | 69 (21.3) | ||
|
| |||||
| Weedy | Tokai | 12 | 1 | 13 | |
| Chugoku/Shikoku | 4 | 7 | 11 | ||
|
| |||||
| Total | 16 (4.9) | 8 (2.5) | 24 (7.4) | ||
|
| |||||
| Grand total | 251 (77.5) | 73 (22.5) | 324 (100.0) | ||
Rice accessions were classified by using Ward’s hierarchical clustering method on the basis of polymorphism data on 64 SSR markers distributed over the 12 rice chromosomes.