近一個月很多老師都在忙著考察品種、收獲試驗材料，為下個月的南繁做準備。南繁管理與北方種地不同，需要注意很多方面，比如：規避臺風、地塊選擇、確定播期、田間管理等等。結合南繁工作，前些年我做了一個播期與產量方面的簡單試驗，還有分享一下南繁的實踐經驗，不足之處，請批評指正。南繁特指全國各地的科技人員利用海南三亞、陵水和樂東等地區的典型熱帶氣候資源以及能夠滿足作物周年生長繁殖的優越生態條件，從每年9月至翌年4月在此進行作物的基礎研究、品種選育、種子鑒定和生產等科研活動。南繁是整個玉米科研工作的主要環(huan)節，在玉米育(yu)種中發揮著重要作用。

      每(mei)(mei)年冬季(ji)北方(fang)的(de)(de)科研(yan)育種單位(wei)(wei)都會利(li)用海(hai)(hai)南(nan)(nan)有(you)利(li)的(de)(de)氣候條件(jian)，開(kai)展玉米南(nan)(nan)繁育種工(gong)作，以加快育種進程。每(mei)(mei)年霜降時節過后海(hai)(hai)南(nan)(nan)進入(ru)旱(han)季(ji)，這段時間(jian)最(zui)有(you)利(li)于海(hai)(hai)南(nan)(nan)農業生產。由于海(hai)(hai)南(nan)(nan)獨特的(de)(de)地理(li)位(wei)(wei)置和氣候環境，一(yi)年四(si)季(ji)持(chi)續高(gao)溫，病蟲草害(hai)發生嚴重；冬季(ji)海(hai)(hai)南(nan)(nan)干旱(han)少(shao)雨(yu)，農田(tian)必須臨近(jin)水源，保(bao)證具有(you)良好的(de)(de)灌(guan)溉(gai)條件(jian)；海(hai)(hai)南(nan)(nan)緯度(du)較低(di)，熱帶低(di)壓氣旋常(chang)產生于菲(fei)律賓(bin)附近(jin)的(de)(de)太(tai)平洋面上，形成臺(tai)風時常(chang)登陸海(hai)(hai)南(nan)(nan)；還有(you)每(mei)(mei)年進入(ru)1月(yue)份，受北方(fang)冷空氣南(nan)(nan)下(xia)的(de)(de)影(ying)響，會出現15-20天(tian)的(de)(de)持(chi)續低(di)溫天(tian)氣；諸多因素(su)對(dui)南(nan)(nan)繁工(gong)作帶來不利(li)影(ying)響。基于上述情況，在南(nan)(nan)繁工(gong)作中如何(he)規避臺(tai)風，減少(shao)低(di)溫冷寒、病蟲草害(hai)的(de)(de)影(ying)響，本研(yan)究設計了不同(tong)的(de)(de)播期試(shi)驗，在南(nan)(nan)繁基地進行玉米生長(chang)發育的(de)(de)適(shi)應性研(yan)究，更好的(de)(de)指(zhi)導南(nan)(nan)繁育種工(gong)作。

      1 材料與方法

      1.1 試驗材料:選用目(mu)前我省(sheng)應用的主栽品(pin)種(zhong)和(he)骨(gu)干自(zi)交系(xi)(xi)各 5 個，主栽品(pin)種(zhong)分別為丹(dan)(dan)玉(yu)(yu)405、丹(dan)(dan)科(ke)2151、丹(dan)(dan)玉(yu)(yu)801、丹(dan)(dan)玉(yu)(yu)508 和(he)先玉(yu)(yu) 335；骨(gu)干自(zi)交系(xi)(xi)分別為丹(dan)(dan)299、丹(dan)(dan)717、丹(dan)(dan)TX-2、丹(dan)(dan)D15和(he)PH6WC。

      1.2 試(shi)驗方法:試(shi)驗于2015年冬在三亞崖州(zhou)區(qu)打幫村(cun)丹東農業(ye)科學(xue)院(yuan)海(hai)南育種(zhong)中(zhong)心(xin)試(shi)驗基地進行(xing)。采取分期(qi)播(bo)(bo)種(zhong)方式，盡可(ke)能使玉米生(sheng)長(chang)發育進程處于不同(tong)氣候條(tiao)件下。試(shi)驗裂區(qu)設計，每(mei)個品系(xi)3次重復，小區(qu)行(xing)長(chang)3m，行(xing)距0.5m（大壟雙(shuang)行(xing)），觀察(cha)道1m，隔線空0.5m，每(mei)份材料每(mei)期(qi)次播(bo)(bo)種(zhong)10 行(xing)，面積 15m2。每(mei)間隔10天播(bo)(bo)種(zhong)一期(qi)，播(bo)(bo)種(zhong)日(ri)(ri)期(qi)分別為(wei)10月(yue)30日(ri)(ri)、11月(yue)10日(ri)(ri)、11月(yue)20日(ri)(ri)、11月(yue)30日(ri)(ri)、12月(yue)10日(ri)(ri)、12月(yue)20日(ri)(ri)和12月(yue)30日(ri)(ri)，共播(bo)(bo)種(zhong)7期(qi)。

      1.3 調(diao)(diao)查(cha)(cha)項目:生育期性(xing)狀調(diao)(diao)查(cha)(cha)：包括(kuo)出(chu)苗期、抽雄期、抽絲期、成熟期；植株(zhu)性(xing)狀調(diao)(diao)查(cha)(cha)：包括(kuo)株(zhu)高、穗(sui)(sui)位高、空稈率、倒伏/折率；抗病蟲性(xing)調(diao)(diao)查(cha)(cha)，包括(kuo)莖(jing)腐病、銹(xiu)病、粘(zhan)蟲和玉米螟蟲；果(guo)穗(sui)(sui)性(xing)狀調(diao)(diao)查(cha)(cha)：包括(kuo)穗(sui)(sui)粗、穗(sui)(sui)長(chang)(chang)、穗(sui)(sui)行數、禿尖長(chang)(chang)、百粒(li)重(zhong)、出(chu)籽率、籽粒(li)產(chan)量[5]。

      1.4 分析(xi)方法:試驗數(shu)據利用 Excel 和(he) DPS 軟件進行統計分析(xi)

      2 結果與分析

      2.1 不(bu)同(tong)播期(qi)對(dui)各品系(xi)生(sheng)育(yu)期(qi)的(de)影響(xiang):從表1可以看(kan)出(chu)，5個玉米品種(zhong)(zhong)前五(wu)期(qi)播種(zhong)(zhong)后(hou)(hou)4天(tian)(tian)(tian)出(chu)苗(miao)，后(hou)(hou)兩期(qi)由于溫度(du)有所降低(di)出(chu)苗(miao)延(yan)(yan)(yan)(yan)(yan)遲(chi)接近1 天(tian)(tian)(tian)；由于自交(jiao)(jiao)(jiao)系(xi)沒有雜(za)種(zhong)(zhong)優(you)勢同(tong)比雜(za)交(jiao)(jiao)(jiao)種(zhong)(zhong)出(chu)苗(miao)延(yan)(yan)(yan)(yan)(yan)遲(chi)1天(tian)(tian)(tian)左右。隨(sui)著播期(qi)的(de)延(yan)(yan)(yan)(yan)(yan)后(hou)(hou)，雜(za)交(jiao)(jiao)(jiao)種(zhong)(zhong)和自交(jiao)(jiao)(jiao)系(xi)的(de)抽雄、吐絲和成(cheng)熟期(qi)都(dou)有不(bu)同(tong)程度(du)的(de)延(yan)(yan)(yan)(yan)(yan)遲(chi)。抽雄期(qi)雜(za)交(jiao)(jiao)(jiao)種(zhong)(zhong)延(yan)(yan)(yan)(yan)(yan)遲(chi) 6-9天(tian)(tian)(tian)，自交(jiao)(jiao)(jiao)系(xi)延(yan)(yan)(yan)(yan)(yan)遲(chi)9-12天(tian)(tian)(tian)；吐絲期(qi)雜(za)交(jiao)(jiao)(jiao)種(zhong)(zhong)延(yan)(yan)(yan)(yan)(yan)遲(chi)8-9天(tian)(tian)(tian)，自交(jiao)(jiao)(jiao)系(xi)延(yan)(yan)(yan)(yan)(yan)遲(chi)9-12天(tian)(tian)(tian)；成(cheng)熟期(qi)雜(za)交(jiao)(jiao)(jiao)種(zhong)(zhong)延(yan)(yan)(yan)(yan)(yan)遲(chi)7-10天(tian)(tian)(tian)；自交(jiao)(jiao)(jiao)系(xi)延(yan)(yan)(yan)(yan)(yan)遲(chi)8-12天(tian)(tian)(tian)，說明在(zai)海(hai)南(nan)(nan)播期(qi)后(hou)(hou)推會延(yan)(yan)(yan)(yan)(yan)長(chang)品系(xi)的(de)生(sheng)育(yu)期(qi)。分析原因，主要是每年10月至(zhi)12月中旬(xun)，海(hai)南(nan)(nan)溫光充足(zu)，為農作物(wu)生(sheng)長(chang)提供足(zu)夠的(de)積溫，12月下(xia)旬(xun)至(zhi)1月末，進入海(hai)南(nan)(nan)全(quan)年中最(zui)冷(leng)的(de)一個多月，有記錄記載2008年春節期(qi)間，三亞在(zai)這個時期(qi)的(de)最(zui)低(di)氣溫迫近10℃，作物(wu)生(sheng)長(chang)基本處于停(ting)滯狀(zhuang)態，如果低(di)溫天(tian)(tian)(tian)氣覆蓋整個苗(miao)期(qi)或灌漿期(qi)，則(ze)會明顯(xian)延(yan)(yan)(yan)(yan)(yan)長(chang)玉米生(sheng)育(yu)期(qi)，所以建議在(zai)試材、土地、天(tian)(tian)(tian)氣條件等(deng)允許的(de)情況(kuang)下(xia)盡可能適時早(zao)播，為南(nan)(nan)繁玉米生(sheng)長(chang)提供良好的(de)氣候環境(jing)。

      2.2 不(bu)(bu)同播(bo)(bo)(bo)(bo)(bo)期(qi)對(dui)各品(pin)系(xi)(xi)植株(zhu)(zhu)(zhu)性(xing)(xing)狀的(de)影(ying)響(xiang)=對(dui)不(bu)(bu)同播(bo)(bo)(bo)(bo)(bo)期(qi)品(pin)系(xi)(xi)的(de)植株(zhu)(zhu)(zhu)性(xing)(xing)狀進行調查，取其平均(jun)值記錄于表2。從中可以(yi)看(kan)出，隨(sui)著(zhu)(zhu)(zhu)(zhu)播(bo)(bo)(bo)(bo)(bo)期(qi)的(de)延(yan)遲(chi)，品(pin)系(xi)(xi)之(zhi)(zhi)(zhi)(zhi)間(jian)葉片(pian)數目都(dou)(dou)有(you)(you)一定(ding)程度的(de)增加(jia)，但是(shi)均(jun)沒(mei)(mei)有(you)(you)達到顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)水(shui)平。植株(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)度變化(hua)品(pin)系(xi)(xi)之(zhi)(zhi)(zhi)(zhi)間(jian)存(cun)(cun)(cun)在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)，雜(za)交(jiao)種方(fang)面12月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)期(qi)的(de)株(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)最(zui)高(gao)(gao)(gao)(gao)，顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于11月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue) 20 日(ri)(ri)(ri)(ri)、11月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)和(he)(he)10月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)的(de)播(bo)(bo)(bo)(bo)(bo)期(qi)株(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)，12月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)期(qi)株(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于 10月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)期(qi)株(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)，其它播(bo)(bo)(bo)(bo)(bo)期(qi)間(jian)株(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)不(bu)(bu)存(cun)(cun)(cun)在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)性(xing)(xing)；自(zi)交(jiao)系(xi)(xi)方(fang)面株(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)之(zhi)(zhi)(zhi)(zhi)間(jian)不(bu)(bu)存(cun)(cun)(cun)在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)性(xing)(xing)。穗位方(fang)面品(pin)系(xi)(xi)之(zhi)(zhi)(zhi)(zhi)間(jian)都(dou)(dou)存(cun)(cun)(cun)在(zai)(zai)(zai)較(jiao)大(da)差(cha)異(yi)(yi)(yi)，雜(za)交(jiao)種方(fang)面 12月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)期(qi)的(de)穗位最(zui)高(gao)(gao)(gao)(gao)，顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于11月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)和(he)(he)10月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)的(de)播(bo)(bo)(bo)(bo)(bo)期(qi)穗位，12月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)期(qi)穗位顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于10月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)期(qi)穗位，其它播(bo)(bo)(bo)(bo)(bo)期(qi)間(jian)穗位不(bu)(bu)存(cun)(cun)(cun)在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)性(xing)(xing)；自(zi)交(jiao)系(xi)(xi)方(fang)面12月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)期(qi)的(de)穗位最(zui)高(gao)(gao)(gao)(gao)，顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于10月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)的(de)播(bo)(bo)(bo)(bo)(bo)期(qi)穗位，其它播(bo)(bo)(bo)(bo)(bo)期(qi)間(jian)穗位不(bu)(bu)存(cun)(cun)(cun)在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)性(xing)(xing)。在(zai)(zai)(zai)空(kong)稈(gan)率(lv)上(shang)隨(sui)著(zhu)(zhu)(zhu)(zhu)播(bo)(bo)(bo)(bo)(bo)期(qi)延(yan)遲(chi)，品(pin)系(xi)(xi)之(zhi)(zhi)(zhi)(zhi)間(jian)空(kong)稈(gan)率(lv)都(dou)(dou)有(you)(you)不(bu)(bu)斷增大(da)的(de)趨勢，雜(za)交(jiao)種之(zhi)(zhi)(zhi)(zhi)間(jian)無差(cha)異(yi)(yi)(yi)顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)性(xing)(xing)，自(zi)交(jiao)系(xi)(xi)除了11月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)和(he)(he)11月(yue)(yue)(yue)(yue)(yue)(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)期(qi)空(kong)稈(gan)率(lv)之(zhi)(zhi)(zhi)(zhi)間(jian)不(bu)(bu)存(cun)(cun)(cun)在(zai)(zai)(zai)顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)差(cha)異(yi)(yi)(yi)性(xing)(xing)外，其它播(bo)(bo)(bo)(bo)(bo)期(qi)之(zhi)(zhi)(zhi)(zhi)間(jian)均(jun)達到顯(xian)(xian)著(zhu)(zhu)(zhu)(zhu)水(shui)平。由于整(zheng)個玉米生(sheng)長季沒(mei)(mei)有(you)(you)強風(feng)天氣(qi)，不(bu)(bu)同播(bo)(bo)(bo)(bo)(bo)期(qi)的(de)玉米品(pin)系(xi)(xi)均(jun)沒(mei)(mei)有(you)(you)倒伏和(he)(he)倒折現(xian)象(xiang)發生(sheng)。通過上(shang)述試(shi)驗(yan)結果(guo)知道，南(nan)繁(fan)播(bo)(bo)(bo)(bo)(bo)期(qi)延(yan)遲(chi)一定(ding)程度上(shang)會增加(jia)玉米的(de)葉片(pian)數目、植株(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)度、穗位高(gao)(gao)(gao)(gao)度和(he)(he)空(kong)稈(gan)率(lv)，特別是(shi)空(kong)稈(gan)率(lv)的(de)增加(jia)會降低玉米收獲產量(liang)，影(ying)響(xiang)以(yi)產量(liang)為目標(biao)的(de)繁(fan)殖(zhi)、復配和(he)(he)測配等(deng)試(shi)驗(yan)，所以(yi)南(nan)繁(fan)科研中涉及產量(liang)的(de)試(shi)驗(yan)建議(yi)早(zao)播(bo)(bo)(bo)(bo)(bo)為宜(yi)。

      2.3 不(bu)(bu)同(tong)(tong)(tong)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)各品系病(bing)(bing)(bing)蟲(chong)(chong)(chong)(chong)害的(de)發(fa)生情況:表 3 反應出不(bu)(bu)同(tong)(tong)(tong)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)玉(yu)米(mi)病(bing)(bing)(bing)蟲(chong)(chong)(chong)(chong)害的(de)發(fa)生情況。可以(yi)看出，播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)延(yan)遲莖腐病(bing)(bing)(bing)、銹(xiu)病(bing)(bing)(bing)、粘蟲(chong)(chong)(chong)(chong)和(he)玉(yu)米(mi)螟(ming)蟲(chong)(chong)(chong)(chong)發(fa)病(bing)(bing)(bing)都有不(bu)(bu)同(tong)(tong)(tong)程(cheng)度(du)(du)(du)的(de)增加，播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)越(yue)晚病(bing)(bing)(bing)蟲(chong)(chong)(chong)(chong)害越(yue)重。莖腐病(bing)(bing)(bing)方面品系之(zhi)(zhi)(zhi)間(jian)(jian)表現一(yi)致，12月(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)12月(yue)(yue)(yue)(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)(ri)(ri)以(yi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，其(qi)它播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)間(jian)(jian)不(bu)(bu)存在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)性；銹(xiu)病(bing)(bing)(bing)方面品系之(zhi)(zhi)(zhi)間(jian)(jian)有所(suo)不(bu)(bu)同(tong)(tong)(tong)，雜交種(zhong)12月(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)12月(yue)(yue)(yue)(yue)(yue)(yue)10 日(ri)(ri)(ri)(ri)(ri)(ri)以(yi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，自(zi)交系12月(yue)(yue)(yue)(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)(ri)(ri)以(yi)后(hou)(hou)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)不(bu)(bu)存在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)性，顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)11 月(yue)(yue)(yue)(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)(ri)(ri)以(yi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，12月(yue)(yue)(yue)(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)不(bu)(bu)存在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)性；在(zai)(zai)(zai)粘蟲(chong)(chong)(chong)(chong)發(fa)病(bing)(bing)(bing)上品系之(zhi)(zhi)(zhi)間(jian)(jian)也有所(suo)差(cha)異(yi)(yi)(yi)，雜交種(zhong)方面12月(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)11月(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，12月(yue)(yue)(yue)(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)11月(yue)(yue)(yue)(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，12月(yue)(yue)(yue)(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)11月(yue)(yue)(yue)(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，其(qi)它播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)間(jian)(jian)不(bu)(bu)存在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)性；自(zi)交系方面12月(yue)(yue)(yue)(yue)(yue)(yue)20 日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)(hou)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)11月(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，12月(yue)(yue)(yue)(yue)(yue)(yue)10 日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)(hou)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)11 月(yue)(yue)(yue)(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，11月(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)(hou)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)11月(yue)(yue)(yue)(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，其(qi)它播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)間(jian)(jian)不(bu)(bu)存在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)性。在(zai)(zai)(zai)玉(yu)米(mi)螟(ming)蟲(chong)(chong)(chong)(chong)發(fa)病(bing)(bing)(bing)上品系表現相同(tong)(tong)(tong)，12月(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)11月(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，12月(yue)(yue)(yue)(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)(hou)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)11月(yue)(yue)(yue)(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，12月(yue)(yue)(yue)(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)(hou)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)11月(yue)(yue)(yue)(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)(qian)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，11月(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)(hou)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)高(gao)(gao)(gao)于(yu)10月(yue)(yue)(yue)(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)，其(qi)它播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)(qi)(qi)間(jian)(jian)不(bu)(bu)存在(zai)(zai)(zai)差(cha)異(yi)(yi)(yi)顯(xian)(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)(zhu)性。從病(bing)(bing)(bing)蟲(chong)(chong)(chong)(chong)害發(fa)生程(cheng)度(du)(du)(du)來看，早播(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)(bo)玉(yu)米(mi)病(bing)(bing)(bing)害發(fa)生程(cheng)度(du)(du)(du)輕，可適當縮減防(fang)治病(bing)(bing)(bing)蟲(chong)(chong)(chong)(chong)害農(nong)藥使用(yong)量，降低(di)田間(jian)(jian)管(guan)理(li)難度(du)(du)(du)，保護農(nong)田生態環境(jing)，節省科研投入(ru)。

      2.4 不同播(bo)(bo)(bo)期(qi)果穗(sui)(sui)性(xing)(xing)狀(zhuang)及產(chan)量的(de)(de)變化(hua):對(dui)收(shou)獲后的(de)(de)各品系(xi)(xi)(xi)重(zhong)復小(xiao)區間的(de)(de)果穗(sui)(sui)性(xing)(xing)狀(zhuang)進行(xing)(xing)調查(cha)，取(qu)平(ping)(ping)均(jun)值記錄于表(biao) 4。可以(yi)看出，隨著(zhu)播(bo)(bo)(bo)期(qi)延后，穗(sui)(sui)粗、穗(sui)(sui)長、穗(sui)(sui)行(xing)(xing)數(shu)、百粒重(zhong)和出籽率(lv)等(deng)性(xing)(xing)狀(zhuang)都不斷(duan)(duan)減小(xiao)，而禿尖長不斷(duan)(duan)增(zeng)加。對(dui)比(bi) 10月 30日和 12月 30日播(bo)(bo)(bo)期(qi)，平(ping)(ping)均(jun)穗(sui)(sui)粗雜交(jiao)(jiao)種減小(xiao)了(le)(le)(le)(le) 0.43cm，自(zi)交(jiao)(jiao)系(xi)(xi)(xi)減小(xiao)了(le)(le)(le)(le)0.16cm；平(ping)(ping)均(jun)穗(sui)(sui)長雜交(jiao)(jiao)種減小(xiao)了(le)(le)(le)(le) 2.2cm，自(zi)交(jiao)(jiao)系(xi)(xi)(xi)減小(xiao)了(le)(le)(le)(le) 1.1cm；平(ping)(ping)均(jun)穗(sui)(sui)行(xing)(xing)數(shu)雜交(jiao)(jiao)種減小(xiao)了(le)(le)(le)(le) 0.5 行(xing)(xing)，自(zi)交(jiao)(jiao)系(xi)(xi)(xi)減小(xiao)了(le)(le)(le)(le) 0.4 行(xing)(xing)；平(ping)(ping)均(jun)百粒重(zhong)雜交(jiao)(jiao)種減小(xiao)了(le)(le)(le)(le) 1.8g，自(zi)交(jiao)(jiao)系(xi)(xi)(xi)減小(xiao)了(le)(le)(le)(le) 1.9g；平(ping)(ping)均(jun)出籽率(lv)雜交(jiao)(jiao)種減少(shao)了(le)(le)(le)(le) 4.9%，自(zi)交(jiao)(jiao)系(xi)(xi)(xi)減少(shao)了(le)(le)(le)(le) 6.9%；平(ping)(ping)均(jun)禿尖長雜交(jiao)(jiao)種增(zeng)加了(le)(le)(le)(le) 0.95cm，自(zi)交(jiao)(jiao)系(xi)(xi)(xi)增(zeng)加了(le)(le)(le)(le) 0.98cm。由此可見，播(bo)(bo)(bo)期(qi)延后果穗(sui)(sui)性(xing)(xing)狀(zhuang)向劣(lie)勢方(fang)向發展，直(zhi)接(jie)或(huo)間接(jie)的(de)(de)影響了(le)(le)(le)(le)產(chan)量潛力的(de)(de)發揮(hui)。

      對(dui)不同(tong)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)品(pin)系產(chan)量(liang)(liang)進(jin)行方(fang)差(cha)(cha)(cha)分析和(he)顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)性(xing)檢驗，結果列于(yu)表5。可以看出，雜交種(zhong)(zhong)方(fang)面(mian) 10月(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)產(chan)量(liang)(liang)最(zui)高(gao)(gao)(gao)(gao)達(da) 8544.1kg/hm2，隨播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)延后(hou)產(chan)量(liang)(liang)逐漸降低(di)，12月(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)產(chan)量(liang)(liang)最(zui)低(di)為6285.5 kg/hm2，11月(yue)(yue)(yue)20日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)產(chan)量(liang)(liang)極顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于(yu)11月(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)，12 月(yue)(yue)(yue)10日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)極顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于(yu) 12 月(yue)(yue)(yue) 20 日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)，12 月(yue)(yue)(yue) 20 日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)極顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于(yu) 12 月(yue)(yue)(yue) 30日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)，其(qi)它(ta)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)間不存(cun)在差(cha)(cha)(cha)異顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)性(xing)；自交系的產(chan)量(liang)(liang)變化趨勢與雜交種(zhong)(zhong)相同(tong)， 10月(yue)(yue)(yue)30日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)產(chan)量(liang)(liang)最(zui)高(gao)(gao)(gao)(gao)為 3707.7kg/hm2，12 月(yue)(yue)(yue) 30 日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)產(chan)量(liang)(liang)最(zui)低(di)為 2210.2 kg/hm2，10 月(yue)(yue)(yue) 30 日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)極顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于(yu) 11 月(yue)(yue)(yue) 30 日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)，11 月(yue)(yue)(yue) 20 日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)極顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于(yu) 12 月(yue)(yue)(yue) 10 日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)，11 月(yue)(yue)(yue) 30 日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)前(qian)(qian)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)極顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)高(gao)(gao)(gao)(gao)于(yu) 12 月(yue)(yue)(yue) 20 日(ri)(ri)(ri)(ri)(ri)(ri)之(zhi)(zhi)(zhi)后(hou)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)，12 月(yue)(yue)(yue) 10 日(ri)(ri)(ri)(ri)(ri)(ri)、12 月(yue)(yue)(yue) 20 日(ri)(ri)(ri)(ri)(ri)(ri)和(he) 12 月(yue)(yue)(yue) 30日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)之(zhi)(zhi)(zhi)間均(jun)存(cun)在極顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)差(cha)(cha)(cha)異性(xing)，11 月(yue)(yue)(yue) 10 日(ri)(ri)(ri)(ri)(ri)(ri)和(he) 11 月(yue)(yue)(yue) 30 日(ri)(ri)(ri)(ri)(ri)(ri)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)之(zhi)(zhi)(zhi)間不存(cun)在極顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)差(cha)(cha)(cha)異性(xing)，但差(cha)(cha)(cha)異達(da)到顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)水平，其(qi)它(ta)播(bo)期(qi)(qi)(qi)(qi)(qi)(qi)(qi)(qi)之(zhi)(zhi)(zhi)間不存(cun)在差(cha)(cha)(cha)異顯(xian)(xian)(xian)(xian)著(zhu)(zhu)(zhu)性(xing)。通過以上(shang)品(pin)系產(chan)量(liang)(liang)結果得出，南繁(fan)適時早(zao)播(bo)會有(you)效提高(gao)(gao)(gao)(gao)玉(yu)米產(chan)量(liang)(liang)。對(dui)于(yu)繁(fan)、制種(zhong)(zhong)來說，在躲(duo)避臺風影響后(hou)，盡早(zao)整地、播(bo)種(zhong)(zhong)，充分利用光熱條件，適時灌(guan)溉并加強田間管(guan)理，為實(shi)現(xian)較(jiao)高(gao)(gao)(gao)(gao)產(chan)量(liang)(liang)奠定良好基礎。

      3 結論與討論

      南(nan)繁(fan)已成為玉米科研育種(zhong)工作不可缺少的(de)(de)(de)重要(yao)組成部分，如何保障南(nan)繁(fan)工作安全、順利的(de)(de)(de)進行是一項(xiang)非常重要(yao)的(de)(de)(de)研究課題。由于海南(nan)生(sheng)態氣候條件(jian)與北方(fang)差異很大，在播(bo)種(zhong)時間、農田管理、收獲晾(liang)曬等(deng)各(ge)個環節都(dou)要(yao)盡可能(neng)規(gui)避風(feng)險。每(mei)年(nian)(nian) 10 月(yue)中下旬至 11 月(yue)初(chu)是海南(nan)臺(tai)風(feng)過境(jing)的(de)(de)(de)收尾期，臺(tai)風(feng)對(dui)(dui)南(nan)繁(fan)播(bo)期產生(sheng)極大的(de)(de)(de)危害(hai)，不僅耽誤播(bo)種(zhong)時間，有的(de)(de)(de)甚至播(bo)后(hou)苗(miao)期遭遇(yu)臺(tai)風(feng)影響，導致毀種(zhong)的(de)(de)(de)尷尬局面。2011 年(nian)(nian) 10 月(yue) 4 日強(qiang)臺(tai)風(feng)臺(tai)風(feng)“尼(ni)格”、2012 年(nian)(nian) 10 月(yue)28 日強(qiang)臺(tai)風(feng)“山神(shen)”、2013 年(nian)(nian) 11 月(yue) 4 日超強(qiang)臺(tai)風(feng)“海燕(yan)”及 2016 年(nian)(nian) 10 月(yue) 18 日臺(tai)風(feng)“莎(sha)莉(li)嘉(jia)”等(deng)對(dui)(dui)南(nan)繁(fan)播(bo)種(zhong)造成極大影響，所以(yi)每(mei)年(nian)(nian)播(bo)種(zhong)前要(yao)時時關注(zhu)天氣和菲律(lv)賓洋面衛星云圖(tu)變化(hua)情況，盡可能(neng)躲(duo)避臺(tai)風(feng)帶來(lai)的(de)(de)(de)危害(hai)。

      海南三亞一年四季農田沒有休閑，病蟲草(cao)害嚴重，在防(fang)病蟲害和除(chu)草(cao)環節帶來很(hen)多(duo)壓(ya)力，使用(yong)(yong)人工除(chu)草(cao)費(fei)工費(fei)時，增加科(ke)研成本，利用(yong)(yong)化學除(chu)草(cao)劑除(chu)草(cao)又有很(hen)多(duo)注意(yi)事(shi)項(xiang)，如(ru)果使用(yong)(yong)不(bu)當(dang)將會造成生(sheng)產(chan)事(shi)故，甚至發生(sheng)經(jing)濟(ji)(ji)賠償(chang)。冬季的海南是北方大陸的蔬菜(cai)生(sheng)產(chan)基(ji)地(di)，廣大農民以生(sheng)產(chan)瓜(gua)果蔬菜(cai)為主，經(jing)濟(ji)(ji)效應(ying)極(ji)高。大田作物和蔬菜(cai)在除(chu)草(cao)劑的使用(yong)(yong)上截然不(bu)同(tong)，如(ru)

      果除草劑使用不當導致土壤農藥殘留會對下茬作物產生極大的影響，如果玉米田周圍有種植瓜菜（豇豆、西瓜、黃瓜、茄子等）、芒果(guo)、香蕉等其他作物，除(chu)草劑(ji)使(shi)用(yong)不當發生(sheng)漂移也(ye)會產生(sheng)巨(ju)大危(wei)害(hai)，造成嚴(yan)重的經(jing)濟(ji)損失。玉米田如采用(yong)化學方式除(chu)草，應盡量避免使(shi)用(yong)漂移性強的乙草胺(an)類苗前封閉除(chu)草劑(ji)，建(jian)議(yi)使(shi)用(yong)漂移程度(du)小(xiao)、對(dui)瓜菜危(wei)害(hai)輕的丙草胺(an)、莠(you)去(qu)津類苗后除(chu)草劑(ji)，而且要在無風天氣作業(ye)，并且嚴(yan)格控(kong)制施用(yong)劑(ji)量，不可(ke)盲目增大濃度(du)，以(yi)免對(dui)玉米、周圍瓜菜和(he)后茬作物帶來危(wei)害(hai)。

      冬(dong)季海(hai)南(nan)(nan)(nan)(nan)農(nong)田(tian)作業精細，勞動力投入量很(hen)大(da)，比(bi)如瓜菜栽(zai)種、搭架、灌(guan)溉、田(tian)間(jian)(jian)(jian)管理(li)、果(guo)(guo)蔬采收包(bao)裝等，在(zai)關(guan)鍵(jian)時(shi)(shi)(shi)節(jie)用工(gong)緊張，雇工(gong)成本(ben)很(hen)高。所(suo)(suo)以南(nan)(nan)(nan)(nan)繁(fan)工(gong)作根據當(dang)地(di)的(de)(de)(de)(de)生(sheng)(sheng)(sheng)產(chan)情況合理(li)交錯，以免關(guan)鍵(jian)環節(jie)產(chan)生(sheng)(sheng)(sheng)用工(gong)荒，增(zeng)加(jia)(jia)(jia)不(bu)(bu)(bu)(bu)(bu)必(bi)(bi)要(yao)(yao)的(de)(de)(de)(de)科(ke)研投入。整個海(hai)南(nan)(nan)(nan)(nan)冬(dong)季全季干旱少雨(yu)，農(nong)田(tian)灌(guan)溉是最為(wei)基本(ben)的(de)(de)(de)(de)生(sheng)(sheng)(sheng)產(chan)條件，在(zai)選擇南(nan)(nan)(nan)(nan)繁(fan)田(tian)地(di)時(shi)(shi)(shi)一定(ding)要(yao)(yao)考慮水源因素。在(zai)繁(fan)制種方(fang)面還要(yao)(yao)考慮隔離(li)(li)條件，海(hai)南(nan)(nan)(nan)(nan)農(nong)田(tian)耕地(di)有(you)限、寸(cun)土寸(cun)金，南(nan)(nan)(nan)(nan)繁(fan)單(dan)(dan)(dan)位(wei)眾多，由于空(kong)間(jian)(jian)(jian)隔離(li)(li)條件不(bu)(bu)(bu)(bu)(bu)夠不(bu)(bu)(bu)(bu)(bu)同單(dan)(dan)(dan)位(wei)之(zhi)間(jian)(jian)(jian)經常發生(sheng)(sheng)(sheng)地(di)塊(kuai)沖突，影響南(nan)(nan)(nan)(nan)繁(fan)工(gong)作，建議單(dan)(dan)(dan)位(wei)與農(nong)戶、單(dan)(dan)(dan)位(wei)之(zhi)間(jian)(jian)(jian)相互溝通，在(zai)空(kong)間(jian)(jian)(jian)隔離(li)(li)條件不(bu)(bu)(bu)(bu)(bu)夠的(de)(de)(de)(de)情況下(xia)，如果(guo)(guo)條件允許可(ke)以進行時(shi)(shi)(shi)間(jian)(jian)(jian)隔離(li)(li)。通過本(ben)試(shi)驗研究結果(guo)(guo)認為(wei)，南(nan)(nan)(nan)(nan)繁(fan)播(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)延(yan)(yan)后(hou)(hou)(hou)玉(yu)米(mi)(mi)各個生(sheng)(sheng)(sheng)育(yu)(yu)時(shi)(shi)(shi)期(qi)(qi)(qi)(qi)均勻不(bu)(bu)(bu)(bu)(bu)同程度的(de)(de)(de)(de)延(yan)(yan)遲，整個生(sheng)(sheng)(sheng)育(yu)(yu)期(qi)(qi)(qi)(qi)也(ye)增(zeng)加(jia)(jia)(jia)，播(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)每延(yan)(yan)后(hou)(hou)(hou) 10 天(tian)生(sheng)(sheng)(sheng)育(yu)(yu)期(qi)(qi)(qi)(qi)平均延(yan)(yan)長(chang) 1-2 天(tian)。玉(yu)米(mi)(mi)作為(wei)短(duan)日照作物對(dui)溫光相對(dui)敏(min)感，海(hai)南(nan)(nan)(nan)(nan) 12 月(yue)(yue)下(xia)旬至(zhi) 1 月(yue)(yue)末(mo)氣溫較低(di)(di)，播(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)延(yan)(yan)后(hou)(hou)(hou)以后(hou)(hou)(hou)，玉(yu)米(mi)(mi)生(sheng)(sheng)(sheng)長(chang)所(suo)(suo)需的(de)(de)(de)(de)有(you)效積溫積累時(shi)(shi)(shi)間(jian)(jian)(jian)就會(hui)延(yan)(yan)長(chang)，導(dao)致(zhi)生(sheng)(sheng)(sheng)育(yu)(yu)期(qi)(qi)(qi)(qi)增(zeng)加(jia)(jia)(jia)，同時(shi)(shi)(shi)增(zeng)加(jia)(jia)(jia)了植株和(he)穗(sui)(sui)位(wei)高度；玉(yu)米(mi)(mi)孕穗(sui)(sui)和(he)生(sheng)(sheng)(sheng)殖生(sheng)(sheng)(sheng)長(chang)期(qi)(qi)(qi)(qi)遭遇低(di)(di)溫會(hui)影響果(guo)(guo)穗(sui)(sui)分(fen)化和(he)籽粒灌(guan)漿(jiang)，易發生(sheng)(sheng)(sheng)空(kong)稈(gan)現象，所(suo)(suo)以播(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)延(yan)(yan)后(hou)(hou)(hou)空(kong)稈(gan)率也(ye)有(you)所(suo)(suo)增(zeng)加(jia)(jia)(jia)。生(sheng)(sheng)(sheng)育(yu)(yu)期(qi)(qi)(qi)(qi)延(yan)(yan)長(chang)也(ye)增(zeng)加(jia)(jia)(jia)了病蟲草害(hai)的(de)(de)(de)(de)侵染幾率，每年進入 2-4 月(yue)(yue)份是海(hai)南(nan)(nan)(nan)(nan)病蟲害(hai)的(de)(de)(de)(de)重(zhong)發期(qi)(qi)(qi)(qi)，玉(yu)米(mi)(mi)生(sheng)(sheng)(sheng)長(chang)中(zhong)后(hou)(hou)(hou)期(qi)(qi)(qi)(qi)恰逢該(gai)時(shi)(shi)(shi)期(qi)(qi)(qi)(qi)會(hui)嚴重(zhong)影響玉(yu)米(mi)(mi)產(chan)量。播(bo)(bo)(bo)(bo)期(qi)(qi)(qi)(qi)延(yan)(yan)后(hou)(hou)(hou)玉(yu)米(mi)(mi)果(guo)(guo)穗(sui)(sui)性(xing)狀也(ye)逐(zhu)漸劣化，在(zai)密度和(he)單(dan)(dan)(dan)株穗(sui)(sui)數不(bu)(bu)(bu)(bu)(bu)變的(de)(de)(de)(de)情況下(xia)勢必(bi)(bi)降(jiang)低(di)(di)玉(yu)米(mi)(mi)產(chan)量。每年 3 月(yue)(yue)中(zhong)旬以后(hou)(hou)(hou)海(hai)南(nan)(nan)(nan)(nan)的(de)(de)(de)(de)雨(yu)季逐(zhu)漸開始，不(bu)(bu)(bu)(bu)(bu)確定(ding)性(xing)的(de)(de)(de)(de)降(jiang)雨(yu)說(shuo)來就來，給收獲后(hou)(hou)(hou)的(de)(de)(de)(de)玉(yu)米(mi)(mi)晾曬(shai)帶來不(bu)(bu)(bu)(bu)(bu)利影響，所(suo)(suo)以玉(yu)米(mi)(mi)延(yan)(yan)后(hou)(hou)(hou)播(bo)(bo)(bo)(bo)種也(ye)增(zeng)大(da)了收獲后(hou)(hou)(hou)的(de)(de)(de)(de)晾曬(shai)難(nan)度。綜(zong)上所(suo)(suo)述，南(nan)(nan)(nan)(nan)繁(fan)玉(yu)米(mi)(mi)播(bo)(bo)(bo)(bo)種的(de)(de)(de)(de)最佳(jia)時(shi)(shi)(shi)間(jian)(jian)(jian)在(zai)每年的(de)(de)(de)(de) 10 月(yue)(yue)末(mo)至(zhi) 11 月(yue)(yue)上旬，有(you)特殊的(de)(de)(de)(de)臺(tai)風天(tian)氣影響可(ke)適當(dang)推延(yan)(yan)，這樣可(ke)以降(jiang)低(di)(di)田(tian)間(jian)(jian)(jian)管理(li)難(nan)度、降(jiang)低(di)(di)科(ke)研成本(ben)、獲得較高產(chan)量、方(fang)便晾曬(shai)。儲(chu)運，也(ye)為(wei)北(bei)方(fang)春(chun)季的(de)(de)(de)(de)試(shi)材準(zhun)備贏得充足的(de)(de)(de)(de)時(shi)(shi)(shi)間(jian)(jian)(jian)。