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.營(ying)養(yang)失(shi)調(tiao)。在(zai)雌(ci)穗(sui)分(fen)化(hua)階(jie)段(duan)，如(ru)果(guo)營(ying)養(yang)不(bu)足(zu)
，光(guang)合(he)麵(mian)積(ji)較(jiao)小(xiao)
，有(you)機(ji)物(wu)質(zhi)積(ji)累(lei)少(shao)，雌(ci)穗(sui)發(fa)育(yu)不(bu)良(liang)
，畸(ji)形(xing)率(lv)增(zeng)高(gao)。但(dan)玉(yu)米(mi)生(sheng)長(chang)盛(sheng)期(qi)礦(kuang)物(wu)質(zhi)供(gong)應(ying)過(guo)多(duo)，造(zao)成(cheng)營(ying)養(yang)生(sheng)長(chang)旺(wang)盛(sheng)，生(sheng)殖(zhi)生(sheng)長(chang)減(jian)弱(ruo)
，有(you)機(ji)物(wu)質(zhi)向(xiang)雌(ci)穗(sui)上(shang)分(fen)配(pei)的(de)少(shao)，從(cong)而(er)形(xing)成(cheng)畸(ji)形(xing)穗(sui)。

    4.gaowenganhan。labakouqizhichousuiqianshiyumixushuiliangzuidashiqi，ruguozhegeshiqiganhanqueshang，jiuhuiyingxiangxiongsuidezhengchangkaihuahecisuihuasidechouchu
，zaochengchouxiongtiqiantusiyanchi，huafendeshengmingliruo
，huasirongyikuwei，bunengshoufenshoujing。 

    5.yinyuduoshi。yumichouxiongsanfenshiqi
，yinyulianmian
，guangzhaobuzu
，huafenliyixishuipengzhangerpoliesiwanghuozhanjiechengtuan
，sangshishoufennengli，ercisuihuasiweinengjishishoujing，zaochengyousuiwuzi。 

    二、防止對策

    1.選xuan擇ze優you良liang品pin種zhong，適shi時shi播bo種zhong。玉yu米mi是shi對dui低di溫wen反fan映ying敏min感gan的de作zuo物wu，品pin種zhong間jian對dui低di溫wen反fan映ying敏min感gan程cheng度du不bu同tong，同tong一yi植zhi株zhu的de不bu同tong發fa育yu時shi期qi對dui低di溫wen的de反fan映ying也ye不bu同tong。選xuan擇ze對dui低di溫wen反fan映ying敏min感gan的de品pin種zhong
，在zai雌ci穗sui性xing器qi官guan發fa育yu形xing成cheng期qi遇yu到dao低di於yu生sheng理li下xia限xian溫wen度du的de低di溫wen
，會hui導dao致zhi部bu分fen果guo穗sui畸ji形xing。所suo以yi，選xuan擇ze對dui低di溫wen反fan映ying相xiang對dui較jiao弱ruo的de優you質zhi抗kang病bing品pin種zhong，並bing適shi時shi播bo種zhong

，盡jin量liang避bi開kai當dang地di雌ci穗sui發fa育yu形xing成cheng期qi的de低di溫wen冷leng害hai。

    2.xueruodingduanyoushi。shengchanshangcaiyongdequxiongjishunengyouxiaoxueruodingduanyoushi，jianshaoxiongsuiduicisuideyizhi，tiaozhengyangfendehelifenpei，jiangdiguosuijixinglv。dangxiongsuilujianshi，gexinghuogezhujiangxiongsuibachu，buyaodaidiaogongnengye
，quantianzhiliuyibanxiongsui，shoufenjieshuhou，jiangshengyuyibanxiongsuizaiqudiao
，yijianshaoyangfenxiaohao。 

    3.helishifei。yumicongbajiedaoguosuitusishoujingweiyunsuijieduan，shishengchangfayuzuiwangshengdeshiqi
，ciqiyangfengongyingchongzu，nengjianshaojixingsuidefasheng。jifeiyaopushiyoujifei
、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。