| This study had carried on the preliminary analysis and research on temperature sensitivity (winterness and springness), botanical characteristics, and overwintering rates of filial generations for hybrids between winter type turnip rape (Brassica rapa, Longyou7 and Longyou9 strong in cold hardiness) and spring type turnip rape (Brassica rapa, Parkland). The results showed that all of the F1 generation from hybridization between Longyou7, Longyou9 and Parkland presented winterness, which meant winterness was dominant. And the winterness and springness were separated in F2 and BC1 generations. The separation ratio within F2 generation was 4∶1 and the ratio within BC1 generation when Parkland was used as the recurrent parent was 1∶1. When Longyou7 and Longyou9 were used as the recurrent parents, the separate ratio was 4∶1. Additionally, while wintering rates were used as the indexes of cold hardiness, the results indicated that cold resistance of filial generations from Longyou7 and Parkland was stronger than that from Longyou9 and Parkland, which was consistent with winterness of parents. The cold resistance strength for each generation was in the following order: BC1 with winternss as recurrent parents>F2>F1>BC1 with springnss as recurrent parents. Moreover, correlation and grey correlation analyses showed that overwintering rates were closely related with the main biological characteristics, and the related degree was as the follows: heart leaves>growth habit>winter and spring sex>leaf color. The analysis results showed that the plant morphological characteristics had close relations with cold hardiness. Generally speaking, seedlings with purple heart leaves, light green or dark green leaves, and prostrate or erect growth, were likely to possess the large wintering rates and strong cold resistance. |