Regulating Effects Of Ethephon And Diethyl Aminoethyl Hexanoate (EDAH) On Different Organs Of Spring Maize

The lower plant density in the middle of Yangtze River resulted in decreased yield per area,because yield potential of maize has not been fully tapped.Elevated plant density was an effective mean to increase maize yield,which stalk would become thinner and more vulnerable.Plant growth regulators can adjust plant morphology,which was conducive to improve maize stress resistance and achieve future need grain direct harvest.The experiments selected the common planted cultivars(DH618 and ND7737)and plant growth regulator(ethephon and diethyl aminoethyl hexanoate,EDAH)),set different plant densities(6.0,7.5 and 9.0 plants/m~2)and numbers of regulator(N0(control),N1(used EDAH at V6),N2(used EDAH at V6 and V12)).The plant morphology,stem strength,yield and quality of maize were determined to assess the response to EDAH from different organs of spring maize.With the increase of density,plant and ear height increased significantly,but there was no significant difference between 6.0 and 10.5 plants/m~2.Compared with regulator of N0,plant height decreased 9.4 cm and 41.1 cm respectively for N1 and N2 in 2018,ear height decreased 8 cm and 15 cm.The density and numbers of regulator significantly affected the stem diameter and bending strength.The stem diameter and bending strength decreased as plant density increased from 6.0 plants/m~2 to 9.0 plants/m~2 in two years.Regulator treatment were increased significantly the diameter of 3rd internode and decreased those length.Both N1 and N2 decreased markedly bending strength 24.7%and14.1%respectively than N0,but no affected rind strength.Thus,lodging rate of maize was reduced.The density had not affected the rate of expand leaf and grain dehydration in 2018.However,plant growth regulator was accelerated the speed of expand leaf at V12 stage,and no affected markedly at silk and maturity stage.The SPAD value was elevated by plant growth regulator,especially SPAD values with N1 and N2 increased by 16.7%and 17.7%than control in maturity at 2018.The relative permeability of epicyte with N1 was lower than N0.The plant growth regulator significantly reduced leaf orientation value and increasing density could reduce leaf angle.LAI presented a single-peak curve with time,and leaf area index was the largest at silk stage,and the density significantly affected LAI.LAI values with N1 and N2treatment decreased markedly compared with the control in 2017 and 2018.With the increase of density,dry matter per area in different stage and accumulation of dry matter per area after silk significantly increased.The dry matter per area at silk with N1 and N2was lower than that of control,those at maturity was no significant difference,but accumulation of those after silk was significantly higher than control.