Hi @anusha S ,
You can't pre-populate the branches in a sub-task (e.g. based upon the branch of the parent issue). Branches are associated with Jira issues on the basis of either the branch name or the commits messages (with a Jira id in it). This means that if you use the sub-task id in the commits on the branch that you want to show in Jira, it will show up in the development panel.