Reporting by Release
When you report on a release (e.g. on the project home or in one of the reports) any child iterations are automatically taken into account, and test runs and incidents that are related to the child iterations will get included in the release reports. Child releases (minor or major) on the other hand are not aggregated up into the parent release.
One exception is: Release summary report, Testing Information section: include test cases assigned only to iteration.
Test Case Release Mapping
If you have test cases that are mapped to an iteration but not the corresponding parent release, they are not included in the Test Case report for the release. That's why we recommend that you map test cases to an iteration and also directly to the parent release.
Test Case Auto-Release Mapping on Execution
When you run a test case against an iteration, the system will automatically add the test case to the iteration and the parent release, if the test case is run as part of a Test Set. However it is not done if you simply run the test cases individually.
Test Execution Status and Task Progress
When you have test results that execute against an iteration, or tasks that report progress against an interation, the status and progress values are automatically aggregated to the parent release, and other high-order releases if the release is a Minor Release.