A Strategy for Genetic Analysis of Height Growth in Japanese Cedar

Japanese cedar (Cryptomeria japonica) has been planted widely throughout Japan, and covers an area of 43% of all the artificial forests. Despite the importance of height growth in Japanese cedar, it is more susceptible to environmental factors than other phenotypic characters, such as flowering and wood properties, and little is known about its mechanisms. Recently, we have attempted new genetic research project focused on height growth of Japanese cedar. The objective of this study is to understand the mechanisms of intraspecific variation of tree height and interaction with environment.

  In this report, we will present past research and future plan. We have collected shoot and tree-top of Japanese cedar throughout a year, and investigated the expressed genes by Roche GS FLX. Microarrays were designed by using the data, and the expression analyses demonstrated that expressed genes were dramatically different between in the growing and dormant period. In future studies, Japanese cedar will be grown in environment control rooms to see the response against temperature, light intensity, and water condition, and investigate environmentally-responsive genes. On the basis of the hypothesis that those genes response to environment and promote height growth, SNP will be detected from those genes and investigate the correlation with height by statistical analysis. Furthermore, we are going to study heavy-ion beam induced dwarf mutants to further understand growth mechanisms.