Different Concentrations of Chemical Topping Agents Affect Cotton Yield and Quality by Regulating Plant Architecture

Manual removal of the main stem tips cotton (Gossypium hirsutum L.) is a traditional topping approach in China. However, chemical has become an inevitable trend. Therefore, it great significance to study effect and appropriate concentration agents for advancement whole process mechanization management technology. A two-year field experiment was conducted evaluate effects different methods on yield plant architecture Shihezi, Xinjiang, Plant included manual topping, non-topping as control, (high, medium, low concentrations agent) determine suitable method agent machine-picked cotton. Chemical performed using fortified mepiquat chloride (DPC+). increased seed compared with non-topping. Compared non-topping, high, significantly by 19.5–27.9%, 24.1–29.4%, 24.3–28.4%, respectively. Topping treatment mainly regulated total boll number per unit area affecting had certain positive fiber strength but no significant weight. affected both vertical horizontal characteristics cotton; height low-, medium-, high-concentration treatments 7.2–11.4 cm, 4.0–5.7 2.3–4.4 respectively, decreased 5.1–7.8 8.3–13.5 9.4–16.9 The internodes between high- low-concentration treatments, which showed that higher concentration, lower internodes. controlled increase length upper branches, fruit branch. medium similar topping. role internode cannot be ignored under peak leaf index (LAI) medium- delayed 1 week late growth period (after 28 d) LAI values were duration high prolonged. optimal concentration.