播期对华北平原雨养夏玉米产量形成与资源利用效率的影响

以京农科728（JNK728）和郑单958（ZD958）为材料,设置6月6日（SD1）、6月11日（SD2）、6月16日（SD3）、6月20日（SD4）和6月26日（SD5）5个播期,研究播期对雨养夏玉米产量形成及资源利用效率的影响。结果表明,随播期推迟,雨养夏玉米灌浆期和总生育期逐渐延长;2个品种平均叶面积指数（LAI）和干物质积累总量（DM）均呈先升高后降低的趋势,在SD2和SD3播期吐丝期LAI最高,SD2吐丝期DM显著高于SD1、SD4和SD5处理,SD2和SD3处理收获期DM显著高于SD4和SD5处理。随播期的推迟,雨养夏玉米穗粒数和行粒数先升高后降低,穗行数逐渐减少,千粒重逐渐升高,2个品种平均产量在SD2和SD3最高,分别为9.84×10³和9.51×10³kg/hm²,SD5最低,仅为8.04×10³kg/hm²,SD5比SD1~SD4产量分别降低9.53%、22.44%、18.36%和15.00%;JNK728比ZD958增产9.19%。灌浆期和全生育期内温度和光辐射量与穗粒数呈显著正相关,但抑制了籽粒灌浆,与千粒重呈负相关,因此雨养夏玉米产量随灌浆期和全生育期内温度升高和光辐射量增加而提高。SD1~SD4光能和降水生产效率比SD5分别提高4.9%~17.6%和13.6%~26.8%,SD2~SD5积温生产效率比SD1提高2.8%~13.3%。综上所述,播期可调控雨养夏玉米的生长发育进程、LAI、干物质积累与分配以及产量,提高资源利用效率,华北平原雨养夏玉米选用抗旱性强品种（JNK728）在6月11日-15日播种,产量可以突破9.5×10³kg/hm²。

Effects of Sowing Date on Rain-Fed Summer Maize Yield Formation and Resource Utilization in North China Plain

To study the effects of sowing dates on rain-fed summer maize yield formation and resource utilization, two maize hybrids Jingnongke 728 and Zhengdan 958 were used by five sowing dates, such as June 6th (SD1), June 11th (SD2), June 16th (SD3), June 20th (SD4), and June 26th (SD5) in this study. The results showed that rain-fed summer maize grain filling duration and total growth duration were gradually extended with delayed sowing date. With delayed sowing date, the average leaf area index (LAI) and dry matter accumulation (DM) increased first and then decreased by two varieties. LAI at silking stage of SD2 and SD3 were the highest. DM of SD2 was significantly higher than SD1, SD4 and SD5 at the silking stage, and DM of SD2 and SD3 were significantly higher than that in SD4, and SD5. With delayed sowing date, ear grains number and ear rows number were increased first and then decreased, while rows grain number was decreased and 1000-grain weight was increased. Rain-fed summer maize grain yield (GY) was the highest at SD2 and SD3 with the value 9.84×10³ and 9.51×10³kg/ha and the lowest at SD5 with the value 8.04×10³kg/ha. The yield of SD5 was 9.53%, 22.44%, 18.36%, and 15.00% lower than SD1-SD4, respectively; The GY of Jingnongke 728 increased by 9.19% compared with Zhengdan 958. The temperature and solar radiation hours during grain filling and total growth duration had a significant positive correlation with ear grain number, while playing a significant negative role on grain filling and 1000-grain weight. The production efficiency of solar radiation and rainfall of SD1 to SD4 were higher by 4.9%-17.6% and 13.6%-26.8%, compared with SD5, respectively. While the production efficiency of GDD of SD2-SD5 were higher than SD1 by 2.8%-13.3%. In conclusion, the sowing date could regulate the growth and development process, leaf area index, dry matter accumulation and distribution, and increased yield, and increase resource utilization efficiency. The rain-fed summer maize could achieve 9.5×10³kg/ha higher yield at sowing date June 11th to 15th with drought-resistant hybrids, such as Jingnongke 728 in the North China Plain.