Index on timestamp fields

I have a timestamp without timezone field in one of my tables that is used in the where clause of one of my queries:
WHERE date_trunc('day',"backupReports"."start")= current_date

I also built an index on that column, I'm assuming that by using the date_trunc() function in my where clause forces
pgsqlto perform a sequential scan. 
Is there a better way to do this? The query needs to return the full timestamp, although I am only selecting by date so
changingthe data type for the column won't work. 

Also would saving the value of current_date to a local variable improve performance?

---
David Gardner, IT
The Yucaipa Companies
(310) 228-2855