Abstract:

 To establish evaluation method for low temperature tolerance of rapeseed (Brassica napus L.) at ger? mination stage, 66 rapeseed lines were investigated under the conditions of 22°C and 9°C. The parameters including germination potential, germination rate, germination index and mean germination time were investigated. After eval? uation, materials were categorized by cluster analysis into different low temperature tolerance grades. The results showed that 9°C (low temperature) decreased germination potential, germination rate and germination index, it also prolonged germination time. The materials’temperature tolerances were obvious among types: materials from mid? land were more tolerant than those from north, semi-winter-type lines were more tolerant than spring- and wintertype materials, conventional varieties were more tolerant than hybrids. The evaluation results from single indicators were consistent with those from comprehensive membership values. Among the 66 materials, H5 (hybrid of Qinyou 8 × e6013) was the extremely low-temperature-resistant variety, and S10 (Huifeng 1) was the sensitive one.

Key words:  , rapeseed；germination；low temperature tolerance；membership function；cluster analysis