Effects Of Stalk Mechanical Characteristics And Chemical Components On Lodging Resistance Of Different Maize Cultivars

Seven maize cultivars which were planted in large areas and had different lodging resistance characteristics were tested in this study.The seven maize cultivars were Zhengdan 958(ZD958),Xianyu 335(XY335),Yudan 606(YD606),Denghai 605(DH605),Zhongdan 909(ZD909),Huamei 1(HM1),and Xundan 20(XD20).Researching the differences of different maize lodging resistance at 12leaves-stage(V12),silking stage(R1),25 days after silking(R3),maturity stage(R6),10 days after maturity(TR6).And the reasons for differences in lodging resistance through morphological traits,mechanical characteristics and chemical components were analyzed.The main findings were as follows:1.ZD958,DH605 and ZD909 were moderately-type plant,with similar plant type and stalk morphology.XY335 and HM1,with low ear heights,belonged to tall and short type plants,respectively.ZD958 and XD20 had higher ear height.2.ZD958,XY335,YD606,DH605 and HM1 could all belong to lodging-tolerant cultivars.ZD909 and XD20 were lodging-susceptible cultivars.ZD958 had high pushing resistance(PR)and strong lodging resistance at V12.XY335 had increased lodging resistance after 25 days of silking.The rind penetration strength(RPS)and crushing strength(CS)of YD606 and DH605 contributed more on lodging resistance.HM1 had higher PR values.The mechanical properties of ZD909 and XD20 were both at a low level,and the PR of XD20 was much lower.3.With growth stages,cellulose content(CC),soluble sugar content(SSC),dry matter density(SD)were rose first and then fell in.Lignin content(LC)was increased,and silicon content(Si C),K content(KC)and moisture content(MC)were decreased with time.The stalks of ZD958 had higher SSC and at V12 they were rich in lignin and silicon.XY335 had plumpness stalks,and higher LC,CC and Si C after 25 days of silking.YD606 had a large percentage of dry matter in the stalk.LC,CC,Si C,and KC of XY335 were in the midstream,and SSC increased after 25 days of silking.DH605 had high SD and CC.At early stage,DH605 had high KC,LC and SSC increased after 25 days of silking.HM1 stalks were enriched,with high Si C and CC.And the content of compounds of HM1 changed by a small margin.ZD909 and XD20 had poor levels of enrichment and low compound content in stalks,and the Si C of ZD909 was higher than that of XD20.After maturity,XD20 stalks dry matter dropped rapidly.4.There was a positive correlation between structural carbohydrates,lignin and cellulose and mechanical properties,especially at the late stage.Lignin,cellulose and soluble sugar had greater impact on PR,RPS and CS,respectively.The Si C had a greater positive effect on PR and CS at V12 and TR6.There was a negative correlation between MC,KC and mechanical properties.The high stalk density contributed to the enhancement of the mechanical properties of the stalks.5.ZD958 was rich in lignin and silicon at V12 and showed strong lodging resistance.For XY335,at later stages,the LC increased and the output of cellulose and silicon were low and the MC decreased rapidly.So the stalks became richer,which contributed to increase in lodging resistance.The chemical components and mechanical properties of stalks of YD606 and DH605 were in the upper and middle reaches of the tested cultivars.ZD909 had low levels of stalk compounds,especially soluble sugars.So ZD909 often broke off due to poor levels of stalks when bad weather conditions appeared.The Si C of XD20 was significantly lower than that of ZD909.XD20 had low bark strength,and it was prone to stalk lodging when stalks were not high enough and the high ear heights.The changes of contents of HM1 were smallest.The stalk was enrichment and the stalk rind was hard.Therefore,it was possible to maintain a stable lodging resistance even in the period when the chemical components and mechanical properties of other cultivars changed drastically.Maize lodging resistance was related to genotype and period.LC and SiC had a greater contribution to lodging resistance.At later stages,on the one hand maintaining stalk plumpness was beneficial to the increase of RPS and CS.On the other hand,maintaining SSC at a high level was beneficial to the increase PR and CS.Substantial stalks mainly relied on the accumulation of structural carbohydrates such as lignin and cellulose.The MC and KC had a negative effect on lodging resistance.The inconsistency between the bark and internal filling may lead to breakage.