低氧胁迫下出苗率下降是限制直播稻安全生产的关键问题之一。建立准确、高效的水稻萌发耐淹性鉴定方法，并筛选强萌发耐淹性的水稻种质对直播稻新品种选育具有重要意义。本研究以20份水稻品种为供试材料，设置不同淹水深度（3 cm、6 cm、9 cm、12 cm、15 cm和18 cm）、不同处理温度（20 ℃、25 ℃和30 ℃）和不同淹水天数（3 d、5 d、7 d、9 d、11 d、13 d和15 d）进行萌发耐淹性鉴定，以胚芽鞘长度为指标进行萌发耐淹性评价，旨在明确水稻萌发耐淹性的评价方法。结果表明，水稻种质在淹水临界深度上存在籼粳间差异，粳稻的淹水临界深度为6 cm，而籼稻的淹水临界深度为9 cm；在温度梯度处理中，30 ℃时种质间的胚芽鞘长四分位差最大，因此认为30 ℃是水稻种质萌发耐淹性鉴定的最适温度；调查时期梯度试验表明，淹水11 d时参试种质的胚芽鞘长四分位差最大，因此认为淹水11 d是水稻萌发耐淹性调查的最适时期。本研究建立了一种以纯水隔绝空气，在温度30 ℃、淹水深度9 cm以上、第11 d调查胚芽鞘长度进行水稻萌发耐淹性鉴定的简便方法，为水稻种质资源的大规模鉴定提供了方法基础。依据上述确立的鉴定方法，对140份来自不同地区的水稻种质进行萌发耐淹性评价，筛选获得6份强萌发耐淹性种质（胚芽鞘长≥55 mm），为水稻萌发耐淹性遗传机制解析和育种利用提供材料基础。

The reduction of emergence rate under hypoxia stress is a major constraint to safe production of direct-seeded rice. It is of great significance to establish an accurate and efficient identification method for anaerobic germination tolerance and to screen rice germplasm resources with strong germinability under submerged condition for breeding new cultivars adapted to direct seeding. In this study, 20 rice varieties were used as the test materials, and the germinability under submerged condition was evaluated under different depths of waterlogging (3 cm, 6 cm, 9 cm, 12 cm, 15 cm and 18 cm), different temperature conditions (20 ℃, 25 ℃ and 30 ℃) and different days of waterlogging (3 d, 5 d, 7 d, 9 d, 11 d, 13 d and 15 d), and corresponding coleoptile length was deployed as an index for evaluating anaerobic tolerance at the germination stage. The results showed that the critical depth of flooding was 6 cm for japonica rice and 9 cm for indica rice, with a significant difference between the two subspecies. Under the condition of 30℃, the coleoptile length showed the highest interquartile range among varieties in the gradient temperature treatment. Therefore, it is considered that 30 ℃ is the optimum temperature for identification anaerobic tolerance at the germination stage. The gradient days of waterlogging treatment showed that coleoptile length shown the highest interquartile range after 11 days of waterlogging stress. Therefore, it is considered that 11 day after waterlogging treatment was the best time point to investigate germinability under submerged condition in rice. In summary, a simple and effective method for screening anaerobic germination tolerance was established, with pure water isolated from air at 30 ℃, more than 9 cm depth of waterlogging, and coleoptile length was measured at the 11th day of waterlogging, which provided a method basis for large-scale identification of rice germplasm resources with strong germinability under submerged condition. By taking use of the aforementioned pipeline, 140 germplasm resources released from different regions were screened, and 6 varieties with high anaerobic germination tolerance (coleoptile length≥55 mm) were found, which might provide a material basis for underlying the genetic mechanism and utilization in breeding program adapted to direct seeding.