Determination and Selection of Free Pollination Offspring in Fokienia hodginsii Primary Seed Orchard

In order to understand the growth pattern and genetic variation of Fokienia hodginsii and construct a breeding population,21 free pollinated seeds were collected from the Fokienia hodginsii primary seed orchard established in 1977 for offspring testing.The field experiment used seedling afforestation,a randomized complete block design,and annual growth and preservation rate surveys.At the age of 9 years,the overall growth of tree height,diameter at breast height,and individual standing timber volume in the experimental forest showed a normal distribution.At the age of 1~9 years,there were significant differences in tree height,diameter at breast height,and individual standing timber volume between groups and families in the experimental forest.The interaction effect between families and groups was not significant after the age of 5 years in the experimental forest.The results of annual analysis of variance showed that there were extremely significant differences in the effects of tree height,diameter at breast height,and individual standing timber volume between regions and families in the 1~9 year old experimental forest.The effect of family×region was not significant after 5 years old.At 9 years,the average height,diameter at breast height,and individual standing timber volume of the experimental forest were 12.8%,7.1%,and 11.1% higher than those of the mixed seeds in the primary seed orchard,respectively.Seven fast-growing excellent families were selected based on a breeding value of volume greater than 0 and a selection rate of 35%.The final selection rate was 33.3%,and the average values of tree height,diameter at breast height,and single tree volume were 8.4 m,12.2 cm and 0.0513 m³,with an average genetic gain of 2.16%,4.63% and 14.57%.Excellent individual plants were selected based on a positive breeding value for individual plant volume and a genetic gain greater than 15%.34 excellent individual plants were selected with a selection rate of 4.8%.The average values of tree height,diameter at breast height,and individual tree volume were 9.3 m,14.8 cm,and 0.08 m³,with an average genetic gain of 2.52%,5.46%,and 20.68%.These excellent materials further enrich the breeding population of Fokienia hodginsii and provide a basis for the thinning of poor quality in primary seed orchards.