Northern Japonica rice region is susceptible to cold damage, and breeding cold-tolerant rice varieties is the most direct and effective means to address this issue. In this study, 45 accessions of northern Japonica rice were used as experimental materials. Under 14 °C cold stress, seven indicators including germination potential, germination rate, germination index, vigor index of shoot, vigor index of root, average germination days, and germination coefficient were measured. Multivariate statistical methods such as correlation analysis, principal component analysis (PCA), membership function comprehensive analysis, and cluster analysis, were employed to evaluate cold tolerance. The results showed that all germination indicators exhibited varying degrees of decline under cold stress, with the vigor index of root showing the most obvious decrease. By calculating the membership function values of each indicator, the seven indicators were transformed into two comprehensive indicators through PCA. Cluster analysis was then used to categorize the 45 accessions into four groups, successfully screening 13 cold-tolerant materials. Furthermore, a regression equation was established, which identified that germination potential, germination rate, vigor index of root, and germination coefficient are the key indicators for evaluating cold tolerance in northern Japonica rice at the germination stage.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |