Comparative Study and Early Appraisal and Preliminary Selection on Genetic Basis of Higher Generations Breeding Population of Chinese Fir and One-generation Population

The first open pollination test plantation of Chinese fir was selected as the reference, and the genetic variability of growth traits of the parents open pollination test plantation in the third-generation primary seed orchards of Chinese fir was studied to understand whether the genetic basis of the third-generation breeding population had been narrowed, so as to provide a scientific basis for genetic improvement of higher generation. Based on the results of the third-generation experiment, certain better families of Chinese fir third-generation were selected in the backward selection, and the individual heritability of forward selection was estimated, so as to prepare for the fourth-generation improvement of Chinese fir. The results demonstrated as follows: (1) Compared with the first-generation breeding population, the genetic basis of tree height traits in the third-generation breeding plant was not narrowed after multi-generation breeding selection, and the high-generation breeding has a promising prospect; (2) The seedling height traits of the third-generation test forest of Chinese fir in Suichang had higher genetic variability, and the heritability of family was above 0.8, and the individual heritability was above 0.3. The variability of seedling height was relatively moderation: GCV about 10%. (3) There were 18 families with annual seedling height exceeding the population average in Dongzhang site of Suichang, and there were two families with annual seedling height exceeding times half of the standard deviation (68.1939 cm) of the population: B105-3 and B42-3; (4) In Zhenggangling site, there were 13 families in which the biennial seedling height was higher than the population on average, and there were two families in which the two-year seedling height was more than times half of the standard deviation (2.9049 m) of the population: the mixed Long second-generation, B03-3; (5) The survival rate of Chinese fir plants in the two sites was relatively higher, which indicated that Chinese fir in the experiment had better adaptability to the experimental environment. Among them, there were two families with the highest survival rate in Dongzhang site: B109-3 and B13-3 respectively. Six families were included in the families with the highest survival rate in the site of Zhenggangling: the mixed Long second-generation, a09-3, biclonal-1339, a76-3, b145-3, and b03-3.