As you have certainly read, the Trackers feature is a powerful, flexible tool for recording information about a collection of items.
One of this power is the use and the definition of several "field types".

See Tracker Field Type

Add show=mod, or show=att or show=com or show=view to the url

tiki-view_tracker.php?trackerId=1&show=mod
tiki-view_tracker_item.php?itemId=1&show=mod
tiki-view_tracker_item.php?itemId=1&show=att

There are different ways to do that. But one way that can work
Create a tracker with the setting
Item creator can modify his items? yes
Add to this tracker a field
user selector type with an automatic field feeding with login (option 1)
Assign special perms to the tracker (if not the default configuration)
tiki_p_create_tracker_items for Registered

That's all. In tracker list, a user will sees only its items. He will be able to edit only his items. He will be able to create items. An admin will be able to edit and see all the items and create new one.