pg_dump.. auto backup

I am doing a cronjob to dump pg database everyday.

Below is my script for cronjob.

#!/bin/sh

/usr/local/pgsql/bin/pg_dump -U ganesh --no-owner -d mq > /backupdb/mq.dump

cd /

cd /backupdb/

tar  -czf /backupdb/mq-`date '+%d-%m-%Y'`.tar.gz -R *

This cronjob is schedule to run everyday at 3.30am.

The problem I am facing is the when running the cronjob it is asking for password. If I remove –U ganesh, it is still prompting for password but this time root password.

How do I solve this, when running the pg_dump I don’t want it to prompt for password.

Regards,

ganesh