密度与整枝对抗虫杂交棉产量分布的影响

于2008年在山东临清、嘉祥和金乡三地大田条件下研究了不同密度、不同整枝条件下抗虫杂交棉的库源比例、产量分布和熟相。试验采用裂区设计,主区由去叶枝和留叶枝构成,副区包括3.0、4.5、6.0、7.5株/m^2 4个密度。结果表明：无论是整枝还是密度处理,产量主要分布在棉株下中层（77%～85%）和内围（76%～88%）,上层（15%～23%）和外围（12%～24%）产量分布较少。密度和整枝对棉花产量的空间分布有显著的效应,但两者的互作效应不显著。密度主要影响产量在棉株上的内外分布,随密度升高,产量向内围集中;而整枝则主要影响产量在棉株上的垂直分布,留叶枝使产量上下分布更加分散。土壤肥力和耕作栽培方式的不同可影响叶枝对产量的贡献率,在临清,叶枝对产量的平均贡献率为11.2%;而在嘉祥和金乡,叶枝对产量的平均贡献率分别为19.4%和18.0%。随着密度的升高,叶枝对产量的贡献率显著降低,密度为3.0、7.5株/m^2时3个试验点叶枝对产量平均贡献率分别为24.9%和8.9%。留叶枝未影响棉花熟相,但密度影响熟相。适当提高密度可以降低库源比例,延缓棉花早衰。

Effects of Density and Plant Pruning on Yield Distribution of Hybrid Bt Cotton

The multi-site field experiment was conducted in Linqing,Jiaxiang and Jinxiang county of Shandong Province respectively to study the effects of density and plant pruning on distribution of yield,ratio of sink to source and maturity performance in 2008.A split-plot design with three replications was used for the study.The main plot was plant pruning(removal and retention of VB,while plant density(3.0,4.5,6.0 and 7.5 plants/m2) constituted the subplots.Regardless of plant density or plant pruning,the yield was mainly distributed in the lower and middle fruiting branches(FB,77%～85%) and the inner fruiting nodes(76%～88%),while less distribution was seen in upper FB(15%～23%) and outer fruiting nodes(12%～24%).Both plant density and plant pruning exhibited significant effects on yield distribution,while their interaction effect was not significant.Yield distribution from inner to outer fruiting nodes was mainly affected by plant density,and more yield distribution to inner fruiting nodes was found as plant density increased.Varied yield distribution from upper to lower FB was mainly attributed to plant pruning,while VB-retention resulted in more dispersal in longitudinal distribution.Soil fertility and cultivation patterns affected the contribution rate of VB to yield.The average contribution rate of VB was 19.4% and 18.0% in Jiaxiang and Jinxiang respectively,but it was only 11.2% in Linqing.The contribution rate of VB to yield decreased as plant density increased.The average contribution rate of VB of all sites were 24.9% and 8.9% as plant density were 3.0 and 7.5 plants per square meter,respectively.Plant density affected the maturity performance,while VB-retention did not affect it.Moderate increase in plant density could delay the cotton senescence.