Effects of Defoliation at Different Growth Stages on Growth,Development and Yield of Cotton
To investigate the impact of hail induced leaf damage on cotton growth and boll characteris-tics,a two-factor split-plot experiment was conducted in field with different growth stages(embryonic stage,full bud stage,and flowering and boll stage)for main plots and different artificial defoliation intensities(0,25％,50％,75％and 100％)for subplots.The impact of simulated hail induced leaf damage on agronomic traits,dry matter accumulation and yield components of cotton were analyzed.The results showed that leaf damage affected cotton plant height,number of fruiting branches and biomass,and ultimately affected cotton yield.As the backward of defoliation time and the enhance of defoliation intensity,the plant height of cotton tended to decrease.The average plant height in D4 treatment(defoliation 100％)was 19.80％,13.67％,14.19％and 8.00％lower than that in CK(no defoliation),D1(defoliation 25％),D2(defoliation 50％)and D3(defoliation 75％)treatments,respectively,and the mean number of fruiting branches in D1,D2,D3 and D4 treatments were reduced by 14.61％,25.29％,30.65％and 46.66％,respectively,compared to CK.The effect of defoliation on number of fruiting branches was higher than that on plant height.The effects of remo-ving leaf sources at different stage on the"sink"of cotton were sequenced as flowering and boll stage＞full bud stage＞embryonic stage,and the greater the leaf defoliation intensity was,the greater the impact on the"sink"was.After defoliation 50％at full bud stage,the bud-flower-boll dry matter,boll number per plant and yield increased 12.46％,14.99％and 6.39％,respectively,resulting in an overcompensation phenomenon.In summary,taking appropriate remedial action according to the actual damaging situation of cotton leaves could obtain corresponding yield and thus reduce economic losses.The conclusion could provide the theoretical basis and data support for cultivation management of hail-damaged cotton.
万方数据
维普
