Effects of shading on grain-filling properties and yield of maize at different growth stages

Abstract

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 duration. The yield was significantly different under different shading treatments. The duration of the maximum grain filling and active 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.