一、果穗畸形的主要原因 

    1.障(zhang)礙(ai)性(xing)冷(leng)害(hai)。雌(ci)穗(sui)在(zai)發(fa)育(yu)形(xing)成(cheng)時(shi)受(shou)到(dao)生(sheng)理(li)下(xia)限(xian)低(di)溫(wen)的(de)影(ying)響(xiang)，造(zao)成(cheng)性(xing)器(qi)官(guan)發(fa)育(yu)受(shou)阻(zu)，不(bu)能(neng)進(jin)一(yi)步(bu)分(fen)化(hua)
，部(bu)分(fen)性(xing)器(qi)官(guan)沒(mei)有(you)形(xing)成(cheng)
，果(guo)穗(sui)發(fa)育(yu)不(bu)完(wan)全(quan)而(er)形(xing)成(cheng)畸(ji)形(xing)。

    2.頂端優勢。玉米的雄穗是由頂芽發育而成，生長勢強，雄穗分化比雌穗早7～10天tian，雌ci穗sui是shi由you腋ye芽ya發fa育yu而er成cheng


，發fa育yu較jiao晚wan
，生sheng長chang勢shi較jiao弱ruo，當dang外wai界jie條tiao件jian不bu適shi合he的de時shi候hou
，雄xiong穗sui對dui雌ci穗sui產chan生sheng明ming顯xian的de抑yi製zhi作zuo用yong。如ru營ying養yang不bu良liang時shi，雄xiong穗sui利li用yong頂ding端duan優you勢shi將jiang大da量liang養yang分fen吸xi收shou到dao頂ding端duan，營ying養yang不bu足zu造zao成cheng雌ci穗sui發fa育yu畸ji形xing。 

    3.yingyangshitiao。zaicisuifenhuajieduan

，ruguoyingyangbuzu，guanghemianjijiaoxiao，youjiwuzhijileishao，cisuifayubuliang
，jixinglvzenggao。danyumishengchangshengqikuangwuzhigongyingguoduo，zaochengyingyangshengchangwangsheng，shengzhishengchangjianruo，youjiwuzhixiangcisuishangfenpeideshao，congerxingchengjixingsui。

    4.高gao溫wen幹gan旱han。喇la叭ba口kou期qi至zhi抽chou穗sui前qian是shi玉yu米mi需xu水shui量liang最zui大da時shi期qi，如ru果guo這zhe個ge時shi期qi幹gan旱han缺que墒shang，就jiu會hui影ying響xiang雄xiong穗sui的de正zheng常chang開kai花hua和he雌ci穗sui花hua絲si的de抽chou出chu，造zao成cheng抽chou雄xiong提ti前qian吐tu絲si延yan遲chi，花hua粉fen的de生sheng命ming力li弱ruo，花hua絲si容rong易yi枯ku萎wei，不bu能neng授shou粉fen受shou精jing。 

    5.yinyuduoshi。yumichouxiongsanfenshiqi

，yinyulianmian，guangzhaobuzu
，huafenliyixishuipengzhangerpoliesiwanghuozhanjiechengtuan，sangshishoufennengli，ercisuihuasiweinengjishishoujing，zaochengyousuiwuzi。 

    二、防止對策

    1.xuanzeyouliangpinzhong，shishibozhong。yumishiduidiwenfanyingmingandezuowu，pinzhongjianduidiwenfanyingminganchengdubutong，tongyizhizhudebutongfayushiqiduidiwendefanyingyebutong。xuanzeduidiwenfanyingmingandepinzhong，zaicisuixingqiguanfayuxingchengqiyudaodiyushenglixiaxianwendudediwen，huidaozhibufenguosuijixing。suoyi，xuanzeduidiwenfanyingxiangduijiaoruodeyouzhikangbingpinzhong，bingshishibozhong，jinliangbikaidangdicisuifayuxingchengqidediwenlenghai。

    2.削(xue)弱(ruo)頂(ding)端(duan)優(you)勢(shi)。生(sheng)產(chan)上(shang)采(cai)用(yong)的(de)去(qu)雄(xiong)技(ji)術(shu)能(neng)有(you)效(xiao)削(xue)弱(ruo)頂(ding)端(duan)優(you)勢(shi)

，減(jian)少(shao)雄(xiong)穗(sui)對(dui)雌(ci)穗(sui)的(de)抑(yi)製(zhi)，調(tiao)整(zheng)養(yang)分(fen)的(de)合(he)理(li)分(fen)配(pei)

，降(jiang)低(di)果(guo)穗(sui)畸(ji)形(xing)率(lv)。當(dang)雄(xiong)穗(sui)露(lu)尖(jian)時(shi)，隔(ge)行(xing)或(huo)隔(ge)株(zhu)將(jiang)雄(xiong)穗(sui)拔(ba)出(chu)
，不(bu)要(yao)帶(dai)掉(diao)功(gong)能(neng)葉(ye)
，全(quan)田(tian)隻(zhi)留(liu)一(yi)半(ban)雄(xiong)穗(sui)，授(shou)粉(fen)結(jie)束(shu)後(hou)，將(jiang)剩(sheng)餘(yu)一(yi)半(ban)雄(xiong)穗(sui)再(zai)去(qu)掉(diao)，以(yi)減(jian)少(shao)養(yang)分(fen)消(xiao)耗(hao)。 

    3.合he理li施shi肥fei。玉yu米mi從cong拔ba節jie到dao果guo穗sui吐tu絲si受shou精jing為wei孕yun穗sui階jie段duan
，是shi生sheng長chang發fa育yu最zui旺wang盛sheng的de時shi期qi，此ci期qi養yang分fen供gong應ying充chong足zu，能neng減jian少shao畸ji形xing穗sui的de發fa生sheng。基ji肥fei要yao普pu施shi有you機ji肥fei
、施入全量磷鉀肥。在玉米5～6葉展開時追施拔節肥，追肥數量占氮肥總量的60%。當玉米12～13片葉展開時，追施攻穗肥
，追餘下40%的氮肥。單一施肥比配方施肥果穗畸形率高，施用二元肥料比三元肥料畸形率高。 

    4.合理密植。在同一密度下，施肥少的比施肥多的畸形率高，肥力越低、密(mi)度(du)越(yue)大(da)，畸(ji)形(xing)率(lv)越(yue)高(gao)。在(zai)種(zhong)植(zhi)形(xing)式(shi)上(shang)要(yao)根(gen)據(ju)品(pin)種(zhong)特(te)征(zheng)特(te)性(xing)合(he)理(li)密(mi)植(zhi)。株(zhu)行(xing)距(ju)增(zeng)大(da)，利(li)於(yu)通(tong)風(feng)透(tou)光(guang)，提(ti)高(gao)光(guang)合(he)能(neng)力(li)，增(zeng)加(jia)果(guo)穗(sui)營(ying)養(yang)
，促(cu)進(jin)果(guo)穗(sui)分(fen)化(hua)，降(jiang)低(di)畸(ji)形(xing)率(lv)。

    5.澆抽雄開花水。玉米抽雄前15天(tian)對(dui)水(shui)敏(min)感(gan)，此(ci)時(shi)土(tu)壤(rang)幹(gan)旱(han)若(ruo)能(neng)及(ji)時(shi)澆(jiao)水(shui)

，可(ke)促(cu)進(jin)果(guo)穗(sui)發(fa)育(yu)，縮(suo)短(duan)雌(ci)雄(xiong)花(hua)的(de)時(shi)間(jian)差(cha)，利(li)於(yu)正(zheng)常(chang)授(shou)粉(fen)授(shou)精(jing)，降(jiang)低(di)畸(ji)形(xing)果(guo)率(lv)，若(ruo)土(tu)壤(rang)含(han)水(shui)量(liang)低(di)於(yu)田(tian)間(jian)最(zui)大(da)持(chi)水(shui)量(liang)的(de)80%，有條件的地方應立即澆水。