Abstract: 【Objective】 A field experiment was conducted to illustrate grain-filling characteristics of maize hybrids differing in maturities in northeast China, aimed to provide scientific information for the regulation of grain weight and selection of maturity.【Method】 Forty high-yield hybrids differing in maturities were used as experimental materials, and they were planted according to 60 000 plants/hm² with the same environmental conditions. The days of seedling emergence to maturity were investigated, and the whole growing days were applied to divide the maturity of different maize hybrids. The difference of yield and 100-kernel weight of maize hybrids differing in maturities was studied, and the grain-filling processes of maize hybrids differing in maturities were analyzed by Logistic model. The grain-filling parameters of initial grain-filling potential, grain-filling rate and grain-filling duration and their relation to yield were calculated. 【Result】 The results indicated that forty maize hybrids were divided into 4-type maturities according to the whole growing days on the basis of the criterion of Food and Agriculture Organization of the United Nations, and the type I is medium maturity, the type II is mid-late maturity, the type III is late maturity, the type IV is supper-late maturity, respectively. The ratio of type III was 50% and 121-130 d with the whole growing days, the highest among these 4 types, the type I and II were the lowest (12.5%), 101-110 d and 111-120 d with the whole growing days, the ratio of type IV was 25% and 131-140 d with the whole growing days. The yield of late maturity was all the highest among these 4 types, the second of supper-late maturity and the lowest in medium maturity, lower 45%, 44% and 35% than the late maturity, supper-late maturity and mid-late maturity. The yield of mid-late maturity, late maturity and supper-late maturity were not different significantly (P＞0.05), but remarkably higher than medium maturity under trial density (P＜0.05). Initial stage of grain-filling, the 100-kernel weight of medium maturity was the lowest, and highest in the supper-late maturity. After 30 days of grain-filling, the 100-kernel growth rate of mid-late maturity was the fastest among these 4 types, and the slowest in the medium maturity. The tendency of grain-filling rate of these 4 types was expressed in single peak curve; the peak value of medium maturity was the highest, and the lowest in the supper-late maturity. After the peak of grain-filling, the grain-filling rate of supper-late maturity decreased the slowest, and fell the fastest in the medium maturity. The grain-filling processes of maize hybrids differing in maturities were analyzed by Logistic model, and the total filling period could be divided into early stage, middle stage and late stage. The initial grain-filling potential (R₀), maximum grain-filling rate (R_max), grain-filling duration of early stage (T₁), grain-filling rate of middle stage and late stage (v₂, v₃ ) of medium maturity were significantly higher than other three types in this trial, but the active grain-filling period (P), grain-filling duration of middle stage and late stage (T₂, T₃), grain-filling rate of early stage (v₁) were remarkably lower than the other three types. Furthermore, correlation analysis showed that active grain-filling period, effective grain-filling time (t₃), grain-filling duration of early stage, grain-filling rate of middle stage and late stage were significantly and positively correlated to yield, and initial grain-filling potential, maximum grain-filling rate, grain-filling duration of early stage, grain-filling rate of middle stage and late stage were significantly and negatively correlated to yield. 【Conclusion】 Medium maturity varieties were quickly in launch of grain-filling, short time of active grain-filling period and effective grain-filling time, but the mid-late maturity, late maturity and supper-late maturity varieties were slowly in launch of grain-filling, long time of active grain-filling period and effective grain-filling time. Prolonging the active grain-filling period, effective grain-filling time, grain-filling duration of middle stage and late stage and enhancing the mean grain-filling rate of early stage can improve grain yield of maize hybrids differing in maturities.

Key words: spring maize, maturity, grain-filling, yiel