Effects Of Planting Density And Topping Methods On Growth And Yield,Fiber Quality Of Different Cotton Varieties

This experiment was carried out in 2017 in the agricultural laboratory of the third division of Xinjiang production and Construction Corps.Two varieties with obvious differences in growth and appearance were selected as experimental materials:Lu Mian Yan24(LMY24)belongs to the hybrid cotton variety with strong individual growth,with loose plant type,long fruit branch,good boll setting and compensatory property;Xinlu Zhong 61(XLZ61)belongs to the conventional variety with general individual growth,with compact plant type,short fruit branch and general boll setting.The effects of chemical topping and artificial topping on agronomic characters and yield quality of two types of cotton varieties under different density conditions were studied.The main findings are as follows:1.Effects of Planting Density and Topping Methods on the Growth and Development of Different Types of CottonThe height of the first fruit node and the first fruit branch of the cotton plant increased with the increase of density,which had nothing to do with the topping method and the type of variety;the plant height changes among varieties were quite different,and the plant height of XLZ61 increased with the increase of density.The plant height of LMY 24 was the highest under low density(120000 plants/hm~2);the number of fruit branches in the chemical topping treatment increased,and the plant height was higher under the same density;the growth period of the variety prolonged with the increase of density,and the growth of chemical topping The period is slightly longer than manual topping.2.Effects of Planting Density and Topping Methods on Leaf Area and Photosynthetic Rate of Cotton of Different VarietiesDensity decreased,The Leaf Area Index(LAI)decreased,LMY 24 decreased slightly,XLZ 61 decreased greatly;the topping method has a large impact on LAI,and the chemical topping LAI of the same variety and the same density is significantly higher than that of artificial The higher the density,the greater the influence of the topping method on LAI;the lower the density,the increase in the net photosynthetic rate of a single plant in the full flowering stage.The increase of LMY 24 is slightly larger than that of XLZ 61.Different topping methods There is no significant effect on the net photosynthetic rate of a single plant in each growth period.3.Effects of Planting Density and Topping Methods on dry matter accumulation,economic coefficient and yield characteristics of different varietiesWith the decrease of planting density,the accumulation of dry matter per plant increased significantly.Under the same planting density,both artificial topping and chemical topping,the accumulation of dry matter in vegetative and reproductive organs of LMY 24 was significantly higher than that of XLZ 61,showing a stronger growth advantage,and the final biological yield showed the same trend,under the same density,the ratio of chemical topping is less than that of artificial topping,which shows that decreasing the density properly is more advantageous to increase the economic coefficient,but the regrowth after chemical topping is invalid The Boll Weight per plant and Boll number per plant of all cotton combinations increased with the decrease of density,the increasing range of Boll number per plant of LMY24 was higher than that of XLZ 61,and the effect of density on lint percentage of XLZ 61 was greater than that of LMY 24 In the final yield of seed cotton,LMY 24 had obvious advantage in medium and low density,but XLZ 61 had higher yield in medium and high density than that in low density,the yield of LMY 24 was higher under medium and low density,the weight of single boll was decreased by chemical topping,but it was increased in every combination,the yield of seed cotton and lint cotton with chemical topping method was significantly higher than that with manual topping method,which indicated that high yield could be obtained by properly reducing planting density and using chemical topping method,the yield increase of XLZ 61 by chemical topping was larger than that of LMY 24.4.Effects of Planting Density and Topping Methods on Fiber Quality of Different Types of CottonThe key indicators of fiber quality are mainly determined by the genetic factors of the variety,and the density and topping method have no significant influence on it.