Effects of nitrogen application on formation of ear under different densities in sweet corn

Chinese. 以甜玉米甜单8号为材料，在不同种植密度（45000、60000和75000株／hm. ）及不同供氮水平（0、120和240kg,／hm. ）下对果穗产量、穗粒结构、穗部性状形成过程及子粒灌浆动态进行了研究。结果表明：施氮水平、种植密度对甜玉米产量影响显著，施氮可显著提高鲜穗产量与子粒产量；穗长、穗粗的形成贯穿整个果穗发育过程，可用Logistic曲线拟合，分别在吐丝与抽雄期达到最终穗长与穗粗的50％；穗粒数在抽雄期达到最高峰，随时间推进果穗败育粒增加；施氮对单穗重的提高在高密度下最明显。施氮能够促进玉米子粒的灌浆，但不同密度下施氮对灌浆动态的影响明显不同，在4-20 DAP子粒体积、百粒鲜重、灌浆速率均明显升高，且施氮处理高于不施氮处理。[著者文摘]

English. The field experiment with summer sweet corn hybrid Tiandan 8 were carried out at in 2003. The treatment consisted of different plant populations（45 000 plant/ha, 60 000 plant/ha, 75 000 plant/ha） and nitrogen supply rates（0, 120, 240 kg/ha）. Fresh ear yield and its grain components, forrnation of spike characters and grain filling in summer sweet corn were studied. The results showed that the fresh ear yield was apparently affected by nitrogen supply and plant population, sweet corn spike and grain yield were apparently promoted by nitrogen supply. The formation of spike length and width was through whole development of spike, which could be expressed by Logistic equation. The spike length and width could attain to 50 percent at pollination and tasselling differently. The effect of nitrogen supply on weight per spike was maximum under high plant density. Kernel number could come to maximum at tasselling, after then, kernel abortion was improved with time. Grain filling in mid-basal kernels were apparently different at differently nitrogen supply and plant density. In 4 - 20 DAP, the size of fresh grain, grain fresh weight, grain filling rate in the mid-basal kernels were apparently increased, which were higher in nitrogen supply treatments than in treatments without nitrogen supply.