Abstract:

To screen cold-tolerant germplasm resources of japonica rice at the germination stage in Heilongjiang Province, this study used 344 japonica rice varieties as materials and applied two treatments: 25 ℃ (normal temperature) and 15 ℃ (low temperature). Indicators such as germination energy, germination rate, germination index, and mean germination time were measured. Relative values were calculated, and comprehensive evaluation of cold tolerance at the germination stage was conducted using principal component analysis, cluster analysis, and a comprehensive evaluation value (D-value). The results showed that low-temperature stress significantly reduced germination energy (mean decrease of 86.12%), germination rate (mean decrease of 7.62%), and germination index (mean decrease of 52.54%), while significantly prolonging the mean germination time (2.48 days at normal temperature vs. 5.38 days at low temperature). Significant differences in cold tolerance were observed among varieties. Principal component analysis transformed four relative indicators into two comprehensive indices, with a cumulative contribution rate of 88.172%. Cluster analysis divided the tested materials into four cold-tolerance grades; the first group (cold-tolerant type) included 107 accessions, with D-values ranging from 0.895 to 0.751. Finally, ten highly cold-tolerant germplasms, including Dongnong 415, Beidao 16, and Puyu 831, were selected.

Key words: japonica rice, germination stage, cold tolerance, principal component analysis, germplasm screening

摘要：

为筛选黑龙江省粳稻芽期耐冷种质资源，本研究以344份粳稻品种为材料，设置常温（25 ℃）和低温（15 ℃）两种处理，测定其发芽势、发芽率、发芽指数及平均发芽日数等指标，通过计算相对值，并结合主成分分析、聚类分析及综合评价值（D值）对芽期耐冷性进行综合评价。结果表明，低温胁迫显著降低了粳稻的发芽势（平均值下降86.12%）、发芽率（平均值下降7.62%）和发芽指数（平均值下降52.54%），同时显著延长了平均发芽日数（常温2.48 d，低温5.38 d），且不同品种间耐冷性差异显著。主成分分析将4项相对指标转化为2个综合指标，累计贡献率达88.172%；聚类分析将供试材料划分为4个耐冷等级，其中第Ⅰ类群为耐冷型，包含107份材料，D值范围为0.895~0.751。最终筛选出东农415、北稻16、普育831等10份高耐冷性种质。

关键词: 粳稻, 芽期, 耐冷性, 主成分分析, 种质筛选