倒伏不仅是所有自然灾害中造成夏玉米严重减产的主要因素之一,而且导致其无法机械化收获。12叶展(V12)是夏玉米最容易发生倒伏的时期之一,为了明确该时期倒伏减产的原因,在中国农业大学吴桥实验站选用抗倒品种先玉335(XY335)和非抗倒品种浚单20(XD20),在75000株/hm2情况下,设置对照(CK)、根倒(RL)、茎折(SL)三个处理。分析了品种和倒伏类型对夏玉米子粒灌浆特性、穗部性状、产量、产量三要素和产量损失率的影响。结果表明V12倒伏使XY335和XD20显著减产,其中SL造成的减产幅度较RL高,XD20的减产幅度小于XY335。RL使XY335和XD20的产量、穗数、穗粒数、千粒重的损失率分别达到21.1%、7.2%、9.5%、7.3%和19.2%、6.0%、13.6%、11.9%,SL使XY335和XD20产量、穗数、穗粒数、千粒重的损失率分别达到61.0%、22.3%、42.3%、9.5%和41.8%、17.2%、19.4%、14.9%。倒伏后,穗部性状变差,SL的影响大于RL,XD20的穗部性状相对好于XY335。倒伏缩短了灌浆期,SL降幅大于RL。倒伏降低了平均灌浆速率,RL主要降低了XY335的缓增期灌浆速率,SL降低了XY335的渐增期灌浆速率,RL和SL均降低了XD20缓增期灌浆速率。V12倒伏造成夏玉米减产的原因从大到小依次归因于穗粒数、穗数和千粒重的降低；穗粒数下降主要由于穗部性状变差,粒重下降主要由于灌浆期缩短,平均灌浆速率下降。
英文摘要:
The lodging is one of main factors causing yield loss in all the natural disasters, and it leads to unable harvesting mechanization. There is the risk of lodging in all of the growth stages for summer maize, especially at 12 collars (V12). To clarify the reasons for yield loss after lodging at V12, a field experiment was conducted at the Wuqiao Experimental Station of China Agricultural University. Three treatments were designed in the field including control (CK), root lodging (RL), and broken stem (SL) with two maize hybrids (lodging-resistant, XY335; lodging-sensitive, XD20) under the density of 75000 plant?hm?2, and characters of grain filling, ear traits, yield, components of yield and yield loss rate were estimated. The results showed that the yield of XY335 and XD20 was significantly reduced under lodging at V12, the effect of SL was higher than that of RL, and the range of yield loss of XD20 was lower than that of XY335. Ear number, grain number and thousands grain weight (TGW) were reduced evidently under lodging at V12. The loss rate of yield, ear number, grain number and thousands grain weight of XY335 and XD20 under RL was 21.1FfFf,7.2FfFf,9.5FfFf,7.3FfFf and 19.2FfFf,6.0FfFf,13.6FfFf,11.9FfFf, respectively. The loss rate of yield, ear number, grain number and thousands grain weight of XY335 and XD20 under SL was 61.0FfFf, 22.3FfFf, 42.3FfFf, 9.5FfFf and 41.8FfFf, 17.2FfFf, 19.4FfFf, 14.9FfFf, respectively. The characters of ear became bad under lodging at V12, it was worse under SL than RL, and the ear diameter, grain number per row of XD20 under lodging at V12 were more than XY335, and length of bare tip showed converse. The grain filling duration was shorted under lodging at V12, it was shorter under SL than RL, and the decrement in grain filling duration of XY335 under RL was lower than XD20, there was converse result under SL. RL and SL reduced mean grain filling of XY335 and XD20. For XY335, RL mainly decreased the grain filling rate at slowly increasing stage, SL mainly decreased the grain filling rate at slightly increasing stage. For XD20, RL and SL both reduced the grain filling rate at slowly increasing stage. The reasons for the yield loss under lodging at V12 from big to small was reduction of grain number, ear number and TGW; the decrease in grain number per ear was due to the bad ear traits, and the decrease in grain weight was due to the reduction of grain filling duration and average filling rate under lodging.
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