玉米籽粒脱水速率影响因素分析

玉米收获时籽粒含水率是影响机械粒收质量、安全贮藏和经济效益的关键因素,已经成为一个重要的技术与经济问题。当前玉米品种收获期籽粒含水率偏高不仅制约了中国玉米粒收技术的推广、影响到玉米收获及生产方式的转变,也严重影响了玉米品质。从国内外相关文献综述可见,收获期玉米籽粒含水率主要由生理成熟前后籽粒的脱水速率控制,该性状是可遗传的,品种间具有显著的差异;品种间脱水速率与苞叶、穗轴、籽粒特征及果穗大小等许多农艺性状有关;玉米生育后期的空气湿度(环境水分的饱和亏缺程度)、温度、日辐射、风速、降雨等生态气象因子对籽粒脱水速率具有重要影响;播期、种植密度、株行距、水肥管理等栽培措施对籽粒脱水也有一定影响。通过生理成熟时籽粒含水率和生理成熟后籽粒脱水速率参数可预测籽粒的适宜机械收获时间。本文建议,当前选择适当早熟、籽粒发育后期脱水快、成熟与收获时含水量低的品种是中国各玉米产区实现机械粒收技术的关键措施。同时,鉴于籽粒脱水速率受基因型、生态气象因素和栽培措施的共同作用,而中国玉米种植区域广、种植方式与品种类型多,因此,需要深入研究玉米籽粒脱水的生理机制,并在各产区针对籽粒脱水特征开展系统观测,为玉米机械粒收技术的推广和品质改善提供理论依据和技术支撑。

Analysis of Influencing Factors on Kernel Dry-Down-Rate of Maize Hybrids

Grain moisture content of maize is the key factor that affects the quality of mechanical harvesting, safe storable level, and economic benefits. It has become an important technical and economic problem. At present, the high moisture content of grain in the corn harvest period not only restricts the popularization of corn combine harvesting technology, but also affects the change of maize harvest and production mode, and seriously affects the grain quality of maize. A review of relevant literature both at home and abroad shows that the moisture content of grain in harvesting period is controlled mainly by the dry-down rate of grain before and after physiological maturity, and this trait is heritable, and it has a significant difference among maize hybrids. The difference of grain drying rate is closely correlated with many agronomic traits of maize, such as length and thickness of bract, thickness of cob, shape of kernel, and size of ear. The ecological factors such as air humidity (saturation degree of environmental water deficit), temperature, solar radiation, wind speed, rainfall and so on, have important influences on grain drying rate at the late growth stage of maize. Agronomic measurements such as planting density, row spacing, irrigation and fertilization, also have some influence on drying rate of grain. The optimum period of harvesting grain with combine machine can be predicted by the grain moisture content and the drying rate of grain after physiological maturity. In this paper, it is suggested that, at present, the selection of maize hybrids having characteristics of suitable early maturity, and rapid drying rate of ear at grain filling stage and low moisture content of grain at physiological maturity is the key measure to realize grain mechanical harvest in maize production areas in China. At the same time, due to the combined effects on drying rate of grain by genotype, ecological and meteorological factors and cultivation measures, meanwhile, the corn planting regions are wide, the planting patters are diverse, and the maize variety types used are various in China, further studies on the physiological mechanism of kernel dry-down are needed, and systematic observation characteristics of drying rate of grain should be carried out, that will provide a theoretical basis and technical supports for promotion of grain machinery harvesting technology and improvement of maize grain quality.