化控处理时期对玉米植株-根系形态及产量的影响

Effects of chemical regulationon timing on maize plant-root morphology and yield

为进一步明确化控处理时期对玉米冠层、根系形态及产量的影响,2017和2018年在吉林省西部开展2年大田试验,供试品种为‘富民985’,2年均喷施乙烯利类型的化控试剂;其中2017年种植密度为7万和9万株/hm^2,在8和10叶期(T(8+10))、8和16叶期(T(8+16))分别进行化控处理;2018年在8叶期(T(8))、8和16叶期(T(8+16))、16叶期(T(16))分别进行化控处理,种植密度为6和9万株/hm^2。结果表明:1)玉米增密后,倒伏率增加;化控处理可缩短植株节间长,降低株高和穗位高,降低倒伏率,其中T(8+16)处理最为显著;2)化控处理后穗位以上叶片叶面积呈现下降趋势,其中T(8+16)处理能够降低15%以上,从而提高透光率,利于下层叶片进行光合作用;3)化控处理增加玉米根系投影面积和最大扩展宽度,降低顶部夹角,使根系更加平展,增强抗倒伏能力,其中T(8+16)处理效果较为理想;4)T(8+16)处理能增加玉米产量,其中2017年T(8+16)处理与CK相比增加6.5%的产量。所以在玉米群体结构建成的8~9和15~16叶期,运用乙烯利类型化控试剂2次,能够改善穗上群体结构,增强茎秆和根系的抗倒伏能力,维持后期群体结构物质生产能力,提高玉米产量。

In order to study the effects of chemical regulation timing on canopy,root morphology and yield,a field experiment was conducted in the western of Jilin Province in 2017 and 2018.‘Fumin 985’was selected as the experimental material and ethephon type reagent was sprayed for chemical regulation.In 2017,chemical regulation were sprayed at the 8 and 10 leaf stage(T(8+10)),8 and 16 leaf stage(T(8+16)),with the planting densities of 70000 and 90000 plants/hm^2;In 2018,chemical regulation were at 8 leaf stage(T(8)),8 and 16 leaf stage T(8+16),16 leaf stage(T(16)),with the planting densities of 60000 and 90000 plants/hm^2.The results showed:1)The lodging rate increased with the increased planting density.Chemical regulation reduced the lodging rate by reducing plant height,ear height and the internode length of the plant,particularly for T(8+16).2)The leaf area of the leaves above the ear was decreased by chemical regulation;T(8+16)can reduce the leaf area by more than 15%compared to CK,so the light transmittance increased.3)Chemical regulation can effectively increase root projected area and maximum expansion width and reduce the horizontal angle.In particular,T(8+16)regulation enhanced the lodging resistance to a great extent.4)T(8+16)regulation increased the yield of maize,by up to 6.5%compared with CK.Therefore,the application of ethephon type reagent in 8-9 and 15-16 leaf stages during the establishment period of maize population structure can improve the population structure on the ear position and above the ear,enhance the lodging resistance of stem and root,and maintain the production capacity of population structure in the later growth period.