不同播期密度对超早熟短季抗虫棉群体性状的影响

本试验以超早熟短季抗虫棉"546系"为材料,在冀中地区不同播期(播期Ⅰ:5月20日、播期Ⅱ:6月2日、播期Ⅲ:6月14日)和密度(低密度:12万株/hm2、中密度:15万株/hm2、高密度18万株/hm2)处理下进行了群体性状相关特征研究。结果表明:(1)随播期推迟和种植密度降低,群体果枝数均明显降低,播期Ⅲ各密度处理有效果枝数只相当于播期Ⅰ的1/2至1/3。(2)随着播期推迟,各时期群体总花蕾数均明显降低,尤以播期Ⅲ下降幅度大。(3)播期Ⅰ各密度吐絮期群体有效铃数差异不明显,播期Ⅱ中密度处理最高,播期Ⅲ高密度处理最高。(4)适当提高种植密度能够有效减弱晚播对干物质积累的不利影响。然而,播期Ⅲ群体营养物质的积累在盛铃后明显落后于另两个播期。(5)群体生殖体干物重受播期及密度影响较为明显,播期Ⅲ在盛铃期群体生殖体干物质积累大幅度低于播期Ⅰ和播期Ⅱ。(6)各播期叶面积指数动态大体表现为:高密度中密度低密度,然而盛铃期开始密度间差异已不明显,播期Ⅲ盛花期之后叶面积指数下降的速度明显快于前两个播期。研究结果为该类型品种(系)示范推广和生长调控提供了依据。

Effects of sowing date and density on population characteristics of super short-season insec-resistant cotton

Using the super short season insect resistant cotton "546" as materials,the population characteristics were researched under the treatments of different sowing dates (sowing dateⅠ: May 20;sowing dateⅡ: June 2;sowing date Ⅲ: June 14) and sowing densities (low density: 12×10~4 plants/hm~2;middle density: 15×10~4 plants/hm~2;high density: 18×10~4 plants/hm~2 ) in central Hebei areas. The results were as follows: (1) The fruit branch number per unit area reduced obviously with the delay of sowing date and the decrease of planting density. Effective fruitbranches of threedensities under the treatment of sowing date Ⅲ were equivalent to one third to one half of that under sowing dateⅠ treatment. (2) As the sowing date delayed,the number of flowers per unit area decreased obviously at all growing stages,especially for the treatment of sowing date Ⅲ. (3) The number of effective bolls per unit area at boll opening stage was not significantly different among the three densities of sowing dateⅠ,and it was the highest under the middle density of sowing date Ⅱ,and under the high density of sowing date Ⅲ,respectively. (4) The adverse effect on dry matter accumulation for late sowing had been weakened effectively by increasing the density properly. However,the population nutrient accumulation of sowing date Ⅲ lagged dramatically behind the others'. (5) The dry matter accumulation of reproductive organs per unit area was mainly influenced by different sowing dates and densities. And for the treatment of sowing date Ⅲ,the dry matter accumulation of population reproductive organs during the flowering and fruiting stage was lower greatly than those of sowing date Ⅰand Ⅱ. (6) The dynamics of leaf area index (LAI) of all sowing dates generally showed the order of high＞middle＞low density. Since full boll stage,however,the differences among the three densities were not significant,and after full bloom stage the LAI of sowing date Ⅲ was reduced more quickly than the others'. The results have provided a basis for the demonstration and growth regulation of this type variety (strain).