新型杀菌剂‘Cabrio’和‘Opera’对夏玉米穗粒数的调控效应

Effects of new fungicides’Cabrio’and’Opera’on grain number per ear of summer maize

为阐明植物杀菌剂‘Cabrio’和‘Opera’对玉米的增产机理,2011-2015年采用植物杀菌剂对低密度(67500和75000株/hm2)和高密度(90000株/hm2)种植的玉米干物质积累和产量构成因素等指标进行分析。结果表明,9叶期喷施植物杀菌剂在不同密度下均能提高玉米产量,且高密度下增产8.83%,效果更显著。PCA主成分分析表明,增产幅度与穗粒数和千粒重均显著相关,但主要取决于穗粒数。穗粒数的增加主要与籽粒败育减少和结实率的提高显著相关。结合受精结实数据分析,喷施杀菌剂后,低密度和高密度处理的玉米粒败育率分别降低30.20%和36.60%。籽粒败育率的降低与Pn的提高和干物质的积累有关。进一步分析发现,低密度玉米植株棒三叶(穗位叶、穗上叶和穗下叶)吐丝期Pn平均增加49.10%,高密度灌浆中期的Pn平均增加43.49%。喷施杀菌剂后,V6(6叶期)-R1(吐丝期)干重增量与穗粒数的相关性(r=0.669**)高于清水处理(r=0.517*),均呈显著正相关。综上,玉米9叶期喷施杀菌剂可以增强玉米花后光合能力,提高花后干物质积累,促进物质向籽粒中转运,减少籽粒败育,从而显著地提高结实率和穗粒数。同时,有利于延缓植株后期衰老,提高粒重。

In order to explore the mechanism of maize yield increase by ear grain number after spraying plant fungicides’Cabrio’and’Opera’,this study analyzed the dry matter accumulation and yield components of corn under low density(67500 and 75000 plants/hm2)and high density(90000 plants/hm2)conditions from 2011 to 2015.The results show that:The application of plant fungicide at 9 leaf stage can increase yield at different densities.The yield increase was 8.83%at high density,which is more significant.PCA analysis showed that the yield increase was significantly correlated with grain number per ear and 1000-grain weight,but mainly depended on grain number per ear.The increase of grain number per ear was mainly related to the decrease of seed abortion and the significant increase of seed setting rate.After the application of fungicide,the seed abortion rate of low density and high density treatment decreased by 30.20%and 36.60%,respectively.The decrease of seed abortion rate was related to the increase of Pn and dry matter accumulation.Further analysis of the Pn of the three leaves(ear leaf,upper ear leaf and lower ear leaf)of maize plants showed that the average Pn increased by 49.10%at the low density spinning stage,and the average Pn at the high density filling stage increased by 43.49%.From the data analysis of dry matter increase in V6(6 th leaf stage)-R1(silking stage),it was obvious that after spraying fungicide,the correlation between dry weight increment and panicle grain number(r=0.669*)was higher than that of water treatment(r=0.517*),showing significant correlation.In conclusion,the application of fungicides at the 9th leaf stage of maize could enhance the photosynthetic capacity after flowering,improve the accumulation of dry matter after flowering,promote the transport of matter to the grain,reduce the grain abortion,and thus significantly increase the seed setting rate and the number of grains per ear.At the same time,it is beneficial to delay the senescence of late plant and increase the grain weight.