If the parent does not have any subsidiary then you cannot include investment in associate as well? How will the treatment be shown in the individual parents financial statements?
You will take a share (% holding of the parent) of profit after tax from associate and include it in the income statement. In the statement of financial position, account it using equity method.,that is, take the net assets of associate multiplied withthe percentage holding of the parent to get the figure that you will disclosure just below the non-current assets as investment in associate.