Studies On Photo-thermal Characteristics Of The Northern Winter Rape

In order to define the photo-thermmal characteristics of the northern winter rape, the varieties’Longyou No.6’,’Longyou No.7’,’Longyou No.8’,’Longyou No.9’and ’Tianyou No.4’were used as materrials, sowing by stages and differend photoperiods as treatments in Changcha. The results showed that:five northern winter rapeseed were sowed from15th August to23th November and matured from6th May to22th May in Changsha area, and the growth period of five northern winter rapeseed was165-270days and no obvious difference exited in these varieties. The bud differentiation time of five northern winter rapeseed was after mid December, and they all can pass through the bud differentiation stage and completed the entire life. The early seedling period was highly correlated with the whole growth period and the correlation coefficient (R) of effective temperature was greater than0.99. The production of five varieties was629.63-1318.13kg/hm2, and the number of pods per plant was greatest impacted on sowing in the yield structure. Their temperature-sensitive index was6.28-8.23d/℃, and16h photoperiod budding promotion ratio was0.5-7.2%. They all belong to winterness-weak sensitivity to long-day. Also, the’Longyou No.6’and’Longyou No.7’photo-thermal sensitivity was stronger than’Longyou No.8’,’Longyou No.9’and’Tianyou No.4’, and it was consistent with their cold resistance.