播期对玉米干物质积累转运和籽粒灌浆特性的影响

以郑单958和京单58为试验材料,设置春播(5月14日播种)和夏播(6月13日播种)2个播期处理,研究播期对玉米干物质转运和籽粒灌浆特性的影响。结果表明:春播条件下,两品种的粒重、茎鞘、叶片干物质转运率及产量均高于夏播。京单58茎鞘干物质向籽粒的转运能力、粒重及产量均高于郑单958;其中,郑单958和京单58的百粒重分别较夏播高17.2%和15.1%;京单58(42.4 g)比郑单958(35.0 g)高20.9%;夏播条件下郑单958和京单58达到最大灌浆速率的时间(Tmax)较春播分别缩短了5.4 d和3.2 d。京单58的灌浆持续期(P)略短,但灌浆起始势(R0)和最大灌浆速率(Gmax)高于郑单958;粒重与灌浆期平均气温呈显著正相关(相关系数分别为0.78*),与Gmax和R0均呈极显著正相关(相关系数分别为0.91**和0.93**)。由此说明,播期主要是通过温度条件影响玉米干物质积累、转运及籽粒灌浆特性;茎秆干物质向籽粒中转运速率快、灌浆速率高是京单58在春夏播条件下粒重和产量较高的原因。

Effect of Sowing Date on Maize Dry Matter Accumulation,Transformation and Grain Filling Characters

Taking Zhengdan958 (ZD958) and Jingdan 58 (JD58) as materials, this experiment set 2 sowing dates (May 14th in spring and June 13th in summer) treatments to study the effect of different sowing dates on maize dry matter transportation and grain filling characteristics. The results showed that under spring sowing condition the grain weight, stem-sheath, leaf blade dry matter translocation rate, and yield of these 2 varieties were higher than that of sowed in summer date. The stem-sheath transport capacity, grain weight and yield of JD58 was higher than that of ZD958. The 100-grain dry weight of ZD958 and JD58 sowed in spring were 17.2% and 15.1% higher than that of sowed in summer, respectively. The 100-grain dry weight of JD58 (42.4 g) was 20.9% higher than ZD958 (35.0 g). The time reaching the maximum grain filling rate (Tmax) of ZD958 and JD58 under summer sowing condition were 5.4 d and 3.2 d shorter than that of sowed in spring. The grain filling duration (P) of JD58 was slightly shorter than that of ZD958. But the Gmax and R0 of JD58 were higher than that of ZD958. The grain weight significantly and positively correlated with the average temperature at grain filling stage (correlation coefficients were 0.78*), and significantly positively correlated with Gmax and R0 (correlation coefficients were 0.91** and 0.93**, respectively). Therefore, sowing date affected maize dry matter accumulation, transportation and grain filling characteristics mainly by temperature condition. The reason for JD58 having higher grain weight and yield relied on its faster transportation rate of dry matter from stem-sheath to grain and higher grain filling speed under spring and summer sowing conditions.