| The responses of different planting densities (45 000(D1)、 60 000(D2)、 75 000(D3)、 90 000(D4) plants·hm-2 and 105 000(D5) plants·hm-2) on dry matter accumulation and transportation of spring maize varieties were studied in 2012 and 2013 through field experiments using Zhengdan958 and Weike702, the main materials in the West Liaohe plain. The results showed that yields of two varieties, and accumulation and transportation of matter followed the same patterns with the changes of planting density. The yields of two varieties were decreased first and then became increased with the planting density enhanced, reaching the highest under the D4 density. Zhengdan958 had the highest yield of 13.945 t·hm-2(2012) and 13.981 t·hm-2(2013), and Weike702 had the highest yield of 16.088 t·hm-2(2012) and 14.606 t·hm-2(2013). With the increase of planting density, dry matter accumulation levels of two varieties became increased before silking, and were subsequently decreased. The overall accumulation rates were increased before silking and went decreased afterwards. The contribution rate to grain became elevated first and then dropped with the planting density increased before silking, while after silking, the rate kept increased. With the increase of planting density, leaf, stem and sheath translocation amounts, as well as the translocation rates of stem and sheath, became increased, whereas leaf translocation rate was decreased. The contribution rates of leaves, stems and sheath translocation to grain reached the highest under the D4 density. With the planting density increased, distribution rates of leaves and spikes were decreased, and those of stem and sheath were overall increased. The grain distribution ratios became elevated first and then dropped at immature stage. With the planting density increased, grain number and 1000-grain weight were both decreased. |