Effects of Pruning Methods and Canopy Patterns on the Temporal-Spatial Distribution of Cotton Bolls and Yield

Objective] The purpose of this study was to shape the good canopy structure and achieve efficiency production of cotton. Method] With Jimian 958 as test material, a split-plot field experiment was conducted over two years (2016—2017) to determine the effect of different pruning methods (removal and retention of vegetative branches) and canopy height treatments (high and low staggered canopy, low canopy and high canopy) on the temporal-spatial distribution of cotton bolls, yield and yield components in Baoding. Result] Pruning method and canopy pattern had significant effects on the temporal-spatial distribution of cotton bolls. Regarding temporal distribution, retention of vegetative branch treatment (P₂) significantly increased the number of total bolls (pre-summer, summer and autumn bolls) compared with removal of vegetative branch treatment (P₁). Staggered canopy (C₁) increased the number of pre-summer bolls but resulted in relatively fewer autumn bolls to that of the high canopy (C₃) pattern. Spatial distribution of bolls varied by pruning method, with P₂ treatment producing a greater number of fruit bolls concentrated in the middle part of the plant. P₁ treatment produced a greater number of fruit bolls concentrated in the lower canopy. The combined effects of pruning methods and canopy pattern on seed cotton yield were significant, with the largest yield observed in P₁C₁ (vegetative branch removal×staggered canopy). The P₁C₁ group did not make significant difference in lint yield to the P₂C₁ (vegetative branch retention×staggered canopy) group. Conclusion] The P₂C₁ canopy structure can produce a greater number of fruit bolls concentrated in the middle part of the cotton, enhance the number and proportion of summer bolls, increase the number of bolls per unit area, and produce higher yields while reducing labour usage, material resources and costs. This simplified cultivation measure offers an important opportunity to efficiently achieve high yields of cotton in the Yellow River Region.