湖北林业科技

Gene bank was built by Populus deltoides which were from different regions of United States, through the investigation of phenology and growth, it had a popular variation within the group. The genetic diversity was very rich. It was mainly female plants in the group, it could be more than 60 days on growth period that whose leaves dropped later compared with whose leaves dropped earlier. Correlation analysis showed that leaf length, leaf width, length from the widest part to the base of the leaf were both negative correlation with tree height and diameter, it meant that if the single leaf was larger and the timber volume would be smaller. The tree height, leaf length and petiole length were significant normal distribution（P＞0.05）, and the other characters were not normal distribution（P＜0.05）, but the skewness value and the kurtosis value were mostly close to zero, approximately to a normal distribution. The coefficient of variation of the important characters were from 11% to 29% in the group. There were 32 clones beyond the population mean diameter of 25%, this accounted for 7.13% of the total. In general, it was very rich in genetic diversity, these Populus deltoides which were from different regions of United States had a great value in breeding.