Abstract:

【Objective】 To study effects of spraying chemical topping agent on plant architecture and yield of cotton and evaluation index screening with different number of fruit branches, then determine the best application period of cotton chemical topping, optimize the evaluation indexes of chemical topping in the hope of providing support for the application of chemical topping. 【Methods】 A completely random experimental design was adopted, manual topping was taken as the control, four chemical topping treatments when the number of fruit branches was 9, 10, 11 and 12 were established by selecting chemical topping agent Yaoqiansu and Xianglingzhuan, the plant height and plant height increased amount, length of the inverse first fruit branch to the inverse fourth fruit branch,effective branch rate, fruit nodes number per plant, stem diameter, main stem internodes number plant architecture related indexes, spatial distribution of bolls and seed cotton yield were measured.【Results】 Compared with manual topping, the plant height of cotton was significantly heighten on the condition of spraying chemical topping agent when the number of fruit branches per plant were 9, the fruit nodes number per plant increased in case of spraying Xianglingzhuan while the number of fruit branches per plant were 10 and on the condition of spraying Yaoqiansu when the number of fruit branches per plant were 11 and 12,main stem internodes number per plant increased and the length of the inverse first fruit branch to the inverse fourth fruit branch became even shorter after chemical topping, the effective branch rate in case of spraying Xianglingzhuan while the number of fruit branches per plant were 10, stem diameter after chemical topping, and the spatial distribution of bolls were not much different except the proportion of upper bolls on the condition of spraying Yaoqiansu when the number of fruit branches per plant were 9. There was no significant difference in the yield of seed cotton in case of spraying Xianglingzhuan while the number of fruit branches per plant was 10, on the condition of spraying Yaoqiansu, when the number of fruit branches per plant was 11 and 12, compared with manual topping. Effective branch count per plant (hereinafter referred to as effective branch count) rate could be used as an evaluation index of chemical topping on cotton plant architecture regulation.【Conclusion】 When the number of fruit branches per plant is 10 and 11, the effective branch rate and the number of fruit nodes per plant are the highest, the plant height growth is not large, and the seed cotton yield dose not reduce, the effective branch rate can be taken as the preferred evaluation index for the regulation of chemical topping on cotton plant architecture.

Key words: cotton; chemical topping; plant architecture; yield; evaluation index

摘要：

【目的】研究化学封顶对不同果枝数棉田株型和产量的影响及其评价指标的筛选,分析棉花化学封顶剂摇钱素和向铃转的最佳施药时期,优选化学封顶效果评价指标,为化学封顶筛选应用提供支撑。【方法】采用完全随机区组试验设计,以人工打顶为对照,选择化学封顶剂摇钱素和向铃转,分别设置果枝数9台时、果枝数10台时、果枝数11台时、果枝数12台时4个化学封顶处理,测量棉花株高及株高增长量、倒1果枝~倒4果枝长度、有效果枝数、单株果节数、茎粗、主茎节间数、棉铃空间分布和籽棉产量。【结果】与人工打顶相比,果枝数9台时化学封顶处理的棉花株高显著增加,果枝数10台时施用向铃转、果枝数11台和12台时喷施摇钱素后单株果节数增加,化学封顶后主茎节间数增多、倒1果枝~倒4果枝长度变短,果枝数10台时施用向铃转后有效果枝率、化学封顶后茎粗、除果枝数9台时喷施摇钱素后上部铃占比外棉铃空间分布均变化不大。果枝数10台时喷施向铃转、果枝数11台和12台时喷施摇钱素后籽棉产量与人工打顶相比差异不显著。单株有效果枝率(以下简称果枝率)可作为化学封顶对棉花株型调控的评价指标。【结论】果枝数10台时喷施向铃转、果枝数11台时喷施摇钱素后棉花有效果枝率和单株果节数最高、株高增长量不高、籽棉产量不降低,有效果枝率可用于评价化学封顶对棉花株型调控的首选指标。

关键词: 棉花, 化学封顶, 株型, 产量, 评价指标