不同生育时期遮光对玉米籽粒灌浆特性及产量的影响

Effects of Shading on Grain-Filling Properties and Yield of Maize at Different Growth Stages

为探索不同时期遮光对玉米籽粒灌浆特性和产量的影响,2012—2013年以玉米品种京科968与郑单958为试验材料,在大田条件下用透光率50%的遮阳网分别于13叶全展期(T1)、吐丝期(T2)、吐丝后15 d(T3)遮光处理,每期遮光7 d,以自然光照为对照,并利用Logistic方程y=A/(1+Be–Cx)比较不同遮光处理玉米籽粒灌浆过程。结果表明,不同时期遮光均导致玉米穗粒数、千粒重和产量不同程度降低,且遮光时期越晚降幅越大,其中产量差异显著;遮光导致灌浆高峰持续期与活跃灌浆天数(P)缩短,最大灌浆速率(Gmax)与平均灌浆速率均下降,籽粒终极生长量(A)降低;品种特性决定粒重、穗粒数与灌浆参数的关系,同一品种的粒重与灌浆速率最大时的生长量(Wmax)呈显著正相关,品种间的粒重差异由活跃灌浆天数(P)决定,同一品种的穗粒数与最大灌浆速率(Gmax)呈显著正相关,品种间的穗粒数差异由灌浆速率最大时的生长量(Wmax)决定。选择适宜品种,提高籽粒灌浆速率最大时的生长量(Wmax)与最大灌浆速率(Gmax),并延长活跃灌浆天数(P)是玉米在光胁迫环境下获得高产、稳产的重要途径。

The objective of this study was to explore the effect of shading at different growth stages on grain filling properties and yield of maize （Zea mays L.）. The Field experiments were carried out using maize cultivars （Jingke 968, Zhengdan 958） with shading of 50% at the 13th leaf fully expanded （T1）, the silking （T2） and the15th day after silking （T3） for seven days in 2012-2013. The natural light condition without shading was used as the control. The Logistic equation was used to analyze the grain filling process. The results showed that grains per ear, 1000-kernel weight and yield were all decreased to a different degree under shading conditions at different growth stages, and the decrease rate of grain yield was increased with lasting shading dura-tion. The yield was significantly different under different shading treatments. The duration of the maximum grain filling and ac-tive grain-filling period （P） were shortened, the maximum and mean grain-filling rate （Gmax） decreased and the final grain weight （A） reduced under shading conditions. The relation among grain weight, grain number per ear and grain yield was determined by characteristics of maize cultivar. The grain weight of the same cultivar was significantly positively correlated with grain weight with the maximum grain-filling rate （Wmax）, and the grain weight of different maize cultivars was determined by active grain-filling period （P）. The grain number per ear of the same maize cultivar was significantly positively correlated with Gmax, and the grain number per ear of different maize cultivars was determined by Wmax. It is an important way to keep a high or stable yield by selecting the suitable cultivar, improving Wmax and Gmax and prolonging active grain-filling period （P） under weak light stress.