| In order to increase the new types of cotton in southern Xinjiang,the third division introduced new varieties of medium-staple upland cotton but there are no supporting cultivation techniques,and the yield is low and the quality is low.Chemical regulation is an indispensable technology in the cotton production process.The whole process of cotton planting has been matured,but there is little research on the medium and long cashmere exclusive cotton.For this reason,this article takes Yumian 1,Xinluzhong 47,and 3D08C9.Four treatments were sprayed with the same dose of Mepiquat at different time,forming times,total doses and so on:S1:[3.8 g.hm-2+12 g·hm-2+15 g-hm-2+45 g·hm-2+90 g·hm-2];S2:[12 g·hm-2+15 g·hm-2+45 g·hm-2+90 g·hm-2];S3:[15 g·hm-2+45 g·hm-2+90 g·hm-2)];S4:[45 g·hm-2+90 g·hm-2].Through the research on agronomic traits,dry matter accumulation,cotton yield and fiber quality in different growth stages of medium and long-staple upland cotton,the aim is to select the best varieties of the third division and the optimal number of chemical control for each variety.The main conclusions are as follows:(1)The growth process of medium-staple upland cotton was not significantly affected by the spraying of mepiquat,and the height of cotton plant was significantly inhibited by the spraying of mepiquat chloride.The plant height of the treatment of 3D08C9 was 33.7%lower than that of the S4,and the inhibiting intensity of leaf number and fruit branch number of main stems of different varieties was different.(2)With the increase of application amount and times of pituitamine,the longest fruit branch of cotton moved downward from the top of the main stem,the length of the first fruit node of each fruit branch and each fruit branch decreased,the length of the upper fruit branch and the length of the first fruit node decreased most significantly,the length of the fruit branch could be reduced to 35.61%of the original,and the length of the first fruit node also decreased.37.50%lower.(3)Continuous use of mepiquat chloride can help to increase or maintain nitrogen content in leaves and prolong the functional period of leaves,but inhibit the accumulation of dry matter in stems and leaves to a certain extent.When the cumulative vegetative growth reaches a high value,the application of Mepiquat can promote the accumulation of dry matter in reproductive organs.(4)Spraying mepiquat chloride had no significant effect on fiber length and micronaire value,but had greater effect on breaking strength and length uniformity of some varieties.The length uniformity of S2 of Xinluzhong 47 was 3.5%higher than that of S1,and the breaking strength of S1 of Yumian 1 was 3.1 cN·tex-1 higher than that of S3.(5)The effect of ketamine treatment on the yield components of different varieties was not completely the same.S3 and S4 increased the number of bells in the 1st to 3rd branches of Xinluzhong 47,the number of bells in the 7th to 9th branches,and the three test materials.The bell is ringed at the top,so that the S3 and S4 are more than the S1 and S2.The S1 of Yanmian 1 increased the number of bells in the periphery of 1-3 fruit branches,which made the ringing of single plant S1 in Yanmian 1 SI reduced by 0.6.It can be seen that the use of 2 to 3 times of ketamine in the whole growth period of cotton contributes to the ringing of a single plant.(6)After the treatment with ketamine,the S4 yields of 3D08C9 and Yanmian 1 reached the highest,respectively 6058.6 kg·hm-2 and 5258.2 kg·hm-2,and the S4 of Xinluzhong 47 was less than that of S2.The yield of secondary ketamine was 7237.0 kg·hm-2,which was 389.0 kg·hm-2 lower than that of S2.In general,medium-staple upland cotton should be sprayed twice in the Xiaohaizi area of southern Xinjiang(S4),and sprayed in the flowering and boll period,taking light before and after weighting(the first dose is small,the second dose is larger)... |
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