Mepiquat chloride (MC) has been widely used for the field management of cotton (Gossypium hirsutum L.) and could enhance yield and quality. However, it is not completely clear how MC influences cotton development. A field study was conducted during 2011∼2012 cotton growing seasons to determine the effects of multiple MC applications (from the late seedling stage to near cutout) on the development of each fruit by calendar days and thermal time. Two cotton cultivars (GX3 and XK4) were used for the study. The MC application significantly hastened the appearance of squares across fruiting positions by 0.4–2.9 d in 2011; and those on upper (from the 11th) fruiting branches and on inner (first two) fruiting nodes of middle (5th-10th) fruiting branches under MC treatment formed 1.8–3.8 d earlier in 2012 compared with control. Also, MC decreased the duration from squaring to flowering by 0.1–0.3 d, and that from bloom to boll opening by 0.9–2.1 d. The MC application reduced the growing degree days (GDD) of most fruiting positions from planting to squaring owing to the early onset of squares. However, it increased the GDD of cotton bolls on the upper fruiting branches during maturation period, presumably due to their early set which exposed them to the higher temperatures during development. These results have improved our understanding of MC-induced earliness in cotton and could help growers to optimize earliness management.

中文翻译：

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多用氯化强草促进棉花从方形萌发到开铃的全株果实发育

氯化肥草快 (MC) 已广泛用于棉花 ( Gossypium hirsutum )的田间管理L.) 并可以提高产量和质量。然而，MC如何影响棉花发育尚不完全清楚。在 2011 年至 2012 年棉花生长季节进行了一项田间研究，以确定多个 MC 应用（从幼苗后期到接近断头）对每个果实发育的日历天数和热时间的影响。研究中使用了两个棉花品种（GX3 和 XK4）。2011 年，MC 应用显着加快了果实位置上方块的出现时间 0.4-2.9 天；2012年MC处理的上部（第11）果枝和中部（第5-10）果枝的内（前2个）果节形成较对照提前1.8-3.8 d。此外，MC 减少了从开花到开花的持续时间 0.1-0.3 天，从开花到开铃的持续时间减少了 0.9-2.1 天。MC 应用减少了大多数结果位置从种植到成平方的生长度天数 (GDD)，因为平方的早期发生。然而，它增加了成熟期间上部果枝上棉铃的 GDD，可能是由于它们的早期坐果使它们在发育过程中暴露在较高的温度下。这些结果提高了我们对 MC 诱导棉花早熟的理解，可以帮助种植者优化早熟管理。