郑单958在东北春玉米区生态适应性研究

为研究郑单958在东北地区的生态适应性，确定其适宜的种植区域，充分发挥郑单958的生产潜力，本文以当地主栽品种为对照，在北纬40°~48°、≥10℃活动年积温在2 916~4 380℃的东北玉米产区开展了郑单958的多点联网试验。结果表明，在东北春玉米区，吐丝至完熟期热量和降水与纬度呈极显著负相关，郑单958的生育进程和产量因各地光热条件不同而表现出较大差异。其中，从播种到完熟/收获的全生育期天数、千粒重、产量均随纬度先增后减，出苗天数和出苗至吐丝天数随纬度北移而延长，吐丝至成熟天数随纬度升高而缩短。各试验点穗粒数与生态条件无显著关系，千粒重随纬度升高先增后减。郑单958高产主要出现在≥10℃活动年积温在3 450~3 700℃地区，当≥10℃活动年积温约低于3 200℃时，不能正常生理成熟，千粒重明显下降。东北春玉米区气候条件差异显著，气象生态条件对郑单958千粒重的影响显著大于对穗粒数的影响，千粒重不同导致其在各地呈现不同的产量表现。在高纬度的低热量地区，造成郑单958减产的主要因素是吐丝至收获期的热量匮乏，依据郑单958对≥10℃活动年积温的响应制定了安全种植北界线，可为其安全推广提供参考。

Ecological Adaptability of Zhengdan 958 Hybrid in Northeast of China

Zhengdan 958 has been the leading maize (Zea mays L.) hybrid in resent years. In order to study its ecological adapta-bility and fully exert its potential productivity, we conducted a group of field experiments at 22 sites with the latitude ranged from N 40°07' to N 48°08' and annul ACT from 2 916 to 4 380℃ in Northeast of China where spring maize were largely grown. The result showed that there were significantly negative correlation between ACT, precipitation and latitude in the post-silking stage (P<0.01).The hybrid grain yield showed a difference with growth process due to the variable thermal conditions. The grain yield,1000-kernal weight, entire growth days obeyed a quadratic relationship (P<0.05), with the latitude ascending, the days of emer-gence were increased and the days from silking to physiological maturity or harvest were decreased. In addition, there was no any significant correlation between latitude and kernel number. The highest potential yield of Zhengdan 958 occurred in some areas where ACT was from 3 450-3 700℃. Zhengdan 958 may not be safely physiological matured where ACT was less than 3 200℃and its kernel weight also decreased fast. The study also showed that meteor-ecological environment has a more significant effect on 1000-kernal weight than on kernel number of Zhengdan 958 under the varied northeastern weather conditions. Therefore, dif-ferent 1000-kernel weight might result in different grain yields in this region. The thermal deficiency in post-silking stage is the leading limit factor in those regions with high latitude and lower temperature where maize yield is lower than that in other areas. A map of the north line for safetly planting the Zhengdan 958 in Northeast was made based on ACT.