Genetic variation analysis of growth and form traits of Castanopsis hystrix in the second generation seed orchard

Objective  To evaluate and utilize the resources in the second generation seed orchard of Castanopsis hystrix, and develop elite genotypes with genetic merit.

Method  We investigated the growth and form traits of 56C. hystrix clones in the second generation seed orchard at Longyandong forest farm, Guangdong Province. The variation coefficients and correlations of different traits were analyzed. Principal component analysis and cluster analysis were performed.

Result  The variation coefficients of ten growth and form traits of 56 C. hystrix clones ranged from 11% to 47%, and the average was 28.2%. Height and diameter at breast height, crown width and height, crown width and diameter at breast height, diameter at breast height and branch number, branch size and leaf density all had significant positive correlations(P<0.01). Crown width and branch angle, taper degree and branch size had significant negative correlations(P<0.05). Principal component analysis indicated that ten traits could be explained by the first three principal components, accounting for 85% of cumulative proportion of variations. Based on hierarchical cluster analysis, 56 clones were divided into four groups.

Conclusion  Growth and form traits among C. hystrix clones had extensive variation with rich genetic diversity. Different degrees of correlations are found among traits. This study provides a basis for parent selection in breeding intraspecific hybrid of C. hystrix.