中文摘要：

利用2011—2014年北方13个省、市、区48个不同生态点的试验数据,分析不同品种在不同生态点的越冬率、产量变化,越冬率与产量的相关性,旨在研究白菜型冬油菜在北方不同生态区的越冬安全性,确定北方冬油菜通用的安全越冬的越冬率临界值,明确影响北方冬油菜越冬率的主要因子。结果表明,不同白菜型冬油菜品种在北方不同生态地区越冬率差异较大,产量也差异较大,越冬率变幅为10%~99%,强抗寒品种越冬率〉70%。回归分析表明,越冬率与产量存在明显的线性正相关,回归方程符合y=ax＋b,当越冬率〈70%时,产量随越冬率的增加而增加,当越冬率为70%时单位面积产量基本趋于稳定,越冬率大于70%时,越冬率对产量的影响不明显。协方差分析表明,与冬油菜越冬率相关性最为密切的因子是品种,其次是极端最低气温、冬季气温、年均气温、≤0℃的冬季负积温、纬度、经度等。因此,70%的越冬率可作为北方地区冬油菜通用安全越冬的越冬率临界值,采用强抗寒品种,极端最低气温–31.79℃、冬季气温–7.20℃、年均气温6.38℃、负积温–997.57℃,纬度低于44.83°,经度高于80.34°是保证冬油菜安全越冬的必要条件。

英文摘要：

To research the safe over-wintering rate of winter rapeseed（Brassica rapa） in different ecological areas in North China, to confirm the critical value of over-wintering rate, and to clarify the main factors affecting over-wintering rate, we collected the data of long term multi-location field experiments at 48 ecological sites in 13 provinces and cities and areas in 2011–2014 with winter rapeseed variety Longyou 7, Longyou 6, Longyou 8, Longyou 9, Tianyou 4, Tianyou 2 to analyze the over-wintering rate and yield and the correlations between them. The results indicated that there were significant differences of over-wintering rate in different ecological areas, which ranged from 10% to 99% and the yield also had significant difference in different locations. The over-wintering rates of varieties with strong cold resistance were over 70%. Regression analysis showed a significant linear correlation between over-wintering rate and yield, with the regression equation of y = ax＋b. The yield increased with the increase of over-wintering rate when the over-wintering rate 70%, and tended to stable when the over-wintering rate was 〈70%, but didn＇t had significant influence on yield when 〉70%. In conclusion, variety is one of the key factors affecting the over-wintering rate of winter rapeseed. The critical value of safe over-wintering rate in north China is 70%, and the corresponding planting conditions are the strong cold resistant varieties, the extreme lowest temperature –31.79°C, the temperature of winter –7.20°C, annual average temperature 6.38°C, negative cumulative temperatures in winter –997.57°C in planting areas, latitude below 44.83° and longitude over 80.34°.