Abstract: Early maturity heterosis of F1 hybrid mainly depends upon the component characteristics of the parental lines. The later the parental maturity is, the higher the significance will be for the F1 positive superiority. The earlier the parenatl maturity is. the weaker the positive superiority will become. When beyong the critical value, it will lead to the negative superiority. There is a significant correlation between F1 early yield superiority to ck and parental eaily yield, and there is also a negative correlation between F1 superiority and difference values of the parental pair. There are similar phenomina for other sub-component traits.The parental lines of a single hybrid with strong early maturity heterosis should be characterized by: ( 1 ) High early yield of fruits and more fruits harvested. (2) More early female flowers and high fruit set on the main stem. (3) Fast fruit growth. (4) Less branches, especially less non-effective early branches. ( 5 ) less early leaf area. ( 6 ) Less leaves at the first flowering stage on the basis of normal plant growth. ( 7 ) Early anthesis. ( 8 ) Lower node height for the first female flower.Early fruit yield could be predicted from the mean values of yield-component traits of the parental pair by multiple regression analysis. The multiple correlation coefficient was R = 0.9916, while the stepwise regression coefficient was R = 0.8945.

Key words: Cucumber, Early maturity heterosis, Parental characteristics, Forecast