<br><div><section class="_135editor" data-role="paragraph" style="font-size: medium; max-inline-size: 100%; margin: 0px; padding: 0px; border: 0px none; z-index: 0; overflow-wrap: break-word !important; outline: none 0px !important;"><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; font-size: 15px; overflow-wrap: break-word !important; outline: none 0px !important;">　　两个遗传性不同的亲本杂交产生的杂种一代（F１）比其双亲在某些性状上优越的现象，叫做杂种优势。利用转外源抗虫基因在棉花中为显性遗传的特点，通过单亲或双亲均携带抗虫基因的亲本材料杂交所生产的F１代，即为抗虫杂交棉。当前生产上利用的抗虫杂交棉以品种间杂交种为主，个别为利用两用系（核不育）配制的杂交种，三系配套（质核不育）的杂交种尚处于研究试验阶段。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; font-size: 15px; overflow-wrap: break-word !important; outline: none 0px !important;">　　与常规抗虫棉相比，抗虫杂交棉最主要的优势是产量高，丰产潜力大，一般比常规品种增产１５％左右，个别优势组合可增产２０％～３０％。多数研究结果认为，单株铃数增多是F１产量优势的主要原因，其次是单铃重的增加，衣分、纤维品质性状的优势较小。除了产量优势以外，抗虫杂交棉的其他农艺性状优势主要表现在出苗好，苗势强，植株健壮，较高大，综合抗逆性强，单株生产潜力大。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; font-size: 15px; overflow-wrap: break-word !important; outline: none 0px !important;">　　抗虫杂交棉适合在肥力较高、灌水较方便的丰产地块种植，并适当降低种植密度（依据地区和习惯，适宜密度为２０００～３０００株／亩），这样才能充分发挥其增产潜力。由于抗虫杂交棉种子的生产成本高，市场价格近几年一直居高不下，所以最好采用营养钵育苗移栽或地膜覆盖精量播种等节种栽培技术，才能在经济上较为划算。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; line-height: 1.75em; overflow-wrap: break-word !important; outline: none 0px !important;"><span style="max-inline-size: 100%; margin: 0px; padding: 0px; cursor: text; font-size: 15px; overflow-wrap: break-word !important; outline: none 0px !important;">　　生产上不提倡利用F２代杂交种。首先是因为棉花杂种二代确实比一代减产，现有最好的组合在试验中也至少减产５％以上；其次，现有多数抗虫杂交棉只有一个亲本是抗虫的，理论上F２代要分离出１／４的非抗虫植株，容易因虫害造成更严重的减产，或增加治虫成本。利用两用系生产的杂交抗虫棉因F２代要分离出一定比例的不育棉株，所以要严禁种植。</span></p><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; overflow-wrap: break-word !important; outline: none 0px !important;"></p></section><section class="_135editor" data-role="paragraph" id="autoparagraph" style="font-size: medium; max-inline-size: 100%; margin: 0px; padding: 0px; border: 0px none; z-index: 0; overflow-wrap: break-word !important; outline: none 0px !important;"><p style="max-inline-size: 100%; margin-bottom: 0px; clear: both; min-height: 1em; cursor: text; overflow-wrap: break-word !important; outline: none 0px !important;"><br style="max-inline-size: 100%; margin: 0px; padding: 0px; font-family: 微软雅黑, &quot;Microsoft YaHei&quot;, sans-serif; font-size: 17px; caret-color: rgb(255, 0, 0); overflow-wrap: break-word !important; outline: none 0px !important;"></p></section></div>