Characterization and Evaluation for Cold Tolerance at the Budburst Period of Rice Germplasm

Cold tolerance at the budburst period (CTBP) for 879 accession of rice were evaluated. The 39 rice varieties with very strong CTBP (grade 1) were selected, and all of which were traditional japonica rice from Guizhou province. 61 23% of evaluated japonica rice varieties have strong CTBP (grade 3), while 13 77% of evaluated indica rice varieties have strong CTBP (grade 3). CTBP of japonica rice was significantly stronger than indica rice. The CTBP of landraces from Guizhou province, either indica rice or japonica rice was significantly stronger than rice varieties from other areas. It is of larger potential to select excellent varieties with very strong cold tolerance.