Study On Yield Components And Formating Machanism Of Double-Stem Cotton

The Jianghuai cotton district is the important high-quality commodity cotton base of our country. It spans two major valley, the low reaches of the Yangzi River and the Yellow River, in our country, annual 200-250 days of frost-free period, accumulated temperature 4500-5300℃(≥10℃). It is prominent day by day that the drawback of current cotton planting system that the growth period is long, the rate of high quality cotton and the benefit is low. In this research, we attempted to use the theory that the blooming and bell-setting period, the best hot season for boll-setting and the period of high fertilizer efficiency is in step and the theory that square-emerging, blooming, boll-setting and boll opening is in mass for the double-stem cotton, utilized the "double stem" advantage of the double-stem cotton to shorten its farm-growing period, exert the population productivity in the period, increase the summer bolls and the early autumn bolls, realize the goal of the high-quality and the high-efficient on the base of high yield. The experiment was carried out in Nanjing, Dongtai, Qidong and with the varieties of Sumian 12, Nankang 3 and Nankang 7 to study the yield components and formating mechanism of double-stem cotton from 2002 to 2004. The main conclusions were as follows:1. The yield of double-stem cotton is high and the fiber quality of it is fine.In this experiment, the seed cotton yield of double-stem cotton was higher 12.72% than that of the single-stem cotton in 2002, and the treatment DS was respectively higher 17.04%, 20.99% than the treatments CKI, CKII in 2004, both on remarkable lever, it was showed on the superiority of boll quantity. Grey correlative degree analysis to the fiber quality of the three treatments in 2004, the results indicated that the fiber quality of double-stem cotton is overall superior to the treatments CKI and CKII.2. The mass boll-setting effect and photosynthesis gathering effect of double-stem cotton.To compare with the single-stem cotton in the same planting period, the farm- growing period of double-stem cotton was shortened about 27 days, and the whole breeding period was shortened 21 days, the first sympodial node fall 1.0 fruit branch location. In the square-emerging fastigium, the average square-emerging intensity of double-stem cotton is 1.4×10⁵·hm^-2·d^-1, and the number of available squares is 2.97×10⁶·hm^-2 were both evidently...