Abstract: 【Objective】 The experiment materials were the varieties released from 1950 with large area application in the production. The trend of quality traits of maize varieties released extensively in different eras in China was studied. The result will be useful for guiding the genetic improvement of quality traits of maize.【Method】Thirty-five cultivars extended in 1950-2000 at large scale were selected. All the varieties were planted in the Shunyi experimental field of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences. Each cultivar was sowed for 5 rows, 3 replications, randomized block design. Two rows in the middle of each plot were reaped. The grain yield and the volume-weight were observed after harvest. The contents of starch, protein and fat of seeds were measured, respectively, with near infrared reflectance spectroscopy (NIRS). ANOVA analysis was made for the quality traits and grain yield. The correlation between the quality traits and grain yield was analyzed. Base on the regression analysis on the mean value of quality traits and yield, the trend of them was studied. 【Result】 Within each decade, the coefficient of variance (CV) was below 10% for the contents of starch and protein and the volume-weight of seed. But the coefficient of variance (CV) was 9.54%-18.74% for the content of fat of seed and 4.53%-33.33% for the grain yield. It meant that the variance range within each decade was small for the content of starch, protein and the volume-weight of seed, but large for the content of fat of seed and the grain yield. The difference of the grain yield between decades was significant, the same as the contents of starch, protein and the volume-weight of seed. The difference in content of fat of seed was not significant. The grain yield of the maize cultivars released extensively increased gradually from 1950 to 2000, average 871 kg•hm-2 per ten years. The content of starch of seed increased generally with the decades, 0.25% per ten years in average. But the content of protein of seed decreased gradually with the decades, 0.31% per ten years in average. The volume-weight also increased generally with the decades, 5.97g•L-1 per ten years in average. The relationship between the content of starch of seed and the grain yield was significantly positive correlation (r=0.493). But the relationship between the content of protein of seed and the grain yield was significantly negative correlation (r=-0.678). It showed that the increase of the starch content and the decrease of the protein content of seeds from 1950 to 2000 was related to the improvement of yield.【conclusion】The grain yield of the maize varieties released extensively was improved greatly from 1950 to 2000. The content of starch and the volume-weight of seed were improved, but the content of protein of seed decreased. The fat content of seed had no obvious changes.

Key words: maize , mainly spreading varieties , starch , protein , fat