Study On The Transnormal Compensation Effects Of Monopodial Branches Retained Cotton (G.hirsutum L.) On The Yield

The field experiments were carried out at test fields of mid-high fertility at CCRI in 2002. Two-factor Split-plot design was apllied, four supplied varieties (G hirsutum L.) as the main treatment , leafy shoots retained at low density and leafy shoots removed at normal density as the sub-treatment, in order to study the compensation effects of cotton leafy shoots retained on the yield under the late conditions of simplify cultivation. Results as follows:Cotton with monopodial branches did have transnormal compensation effects on the yield. The yield of cotton leafy shoots retained at low density and cotton leafy shoots removed at normal density was much at one level. The compensation threshold value of monopodial branches to yields could reach to 46%~57%. Cotton leafy shoots retained could increase boll-setting intensity. During the flower-boll stage, the average boll-setting intensity of cotton leafy shoots retained was 1.9 times of cotton leafy shoots removed. The bolls per unit area of cotton leafy shoots retained at low density could reach the same level as cotton leafy shoots removed at normal density. With leafy shoots retained, monopodial branches did have almost the same contribution to the total boll productivity as sympodial branches. There was no distinct difference on boll weight and lint percent between cotton leafy shoots retained and cotton leafy shoots removed. Leafy shoots retained could enhance the prematurity, the rate of prefrost lint could be increased for 1.1 percents. There was no negtive effects in fiber quality under the condition of leafy shoots retained. There was no significant difference on the fiber quality of whole plant lint and of the lint that harvested in several times between cotton leafy shoot retained and cotton leafy shoots removed. For hybrid cotton, the fiber strength of boll from monopodial branches was higher than that of boll on sympodial branches. For conventional cotton, the fiber strength of boll on monopodial branches was lower than sympodial branches. As a whole, the fiber strength of boll on monopodial branches was some higher than that of boll on sympodial branches. Cotton leafy shoots retained could produce more economic benefits, the value-added rate could reach 6.5 percents. It was indicated that, the useage of monopodial branches could bring up much more economic benefits, while the varieties of still having strong growth potential during the end of cotton growth stage were used, fertilizer was much more applied and simplify cultivation was applied.