Studies On The Adjustable Mechanism Of Boll Development On The Different Positions Of High Quality Cotton Yumian-1

With high quality cotton Yuma No. 1 (Gossipier Hirsutum. L) as the testing material, different combinations of population density, fertilizer and DPC chemical spraying were adopted to study the dynamic changes of endogenous hormone contents, the vigor of source-sink and the nutrient transportations from boll walls to lint cotton as well as fiber qualities on different positions. The main results were as follows:1. The transportation stagnation of nutritional materials such as soluble sugar led to thicker boll walls, split difficultly. Higher IAA content was found in the boll walls both on the middle part of cotton plants during the period of 30-40 days after anthesis and on the upper part of cotton plants during the period of 20-50 days after anthesis respectively. And higher ZR content was also detected in the bolls wall on the middle and upper part of cotton plant on the anthesis date. These might be the factors that led to thicker boll walls by hindering the transportations of nutritional materials such as soluble sugar.2. By adopting suitable population (2500 plants/666.67 m2), nitrogen (20kg/666.67 nr) and DPC spraying (twice), higher GA3 content was induced in the boll walls on the middle and upper part of cotton plants 20 days after anthesis, lower IAA contents werefound in the boll walls both on the middle part of cotton plants during 30-40 days and the upper part of cotton plants during 20~50 days. Meanwhile higher ZR content was also detected in the boll walls on the middle of cotton plants during 20-50 days after anthesis. All these are beneficial to the transportation of soluble sugar from bolls wall to lint yield. While more soluble sugar is stagnated in boll walls (especially boll walls on the upper part of cotton plants) by spraying DPC four times, which led to thicker boll walls.3. By adopting suitable population (2500 plants/666.67 m2), nitrogen (20kg/666.67 m2) and DPC spraying (twice), the assimilation, accumulation, distribution of nitrogen, phosphorus and potassium were promoted in the cotton plants. The contents of chlorophylla, free amino acids and soluble proteins in fruit leaves on the middle and upper part of cotton plants were increased significantly as well, which prolonged the rapid-increasing stages of boll volume, lint cotton and fiber weight, and laid a solid source-sink physiological foundation for fiber yield and quality.4. More potassium was needed for the growth of Yumian No. 1. On the basis of adopting suitable population (2500 plants/666.67 m2), nitrogen (20kg/666.67 m:), phosphorus (40Kg/666.7 m:), potassium(15Kg/666.7 m2), two times of DPC spraying and more potassium, All these are beneficial to the transportation of soluble sugar from bolls wall to lint yield, which led to thinner boll walls, split easily, lint cotton, economic quantity of boll and fiber quality were increased significantly as well.