Assign field symbol to table line?

Hello experts,

is it possible to point a table line to a variable?

I have an itab it_mara type mara with 10 entry´s.

If i type it_mara[1] in debugger the programm points perfectly to the structure of line 1.

If i type it_mara[2] in debugger the programm points perfectly to the structure of line 2.

This function i need in my code but:

assgin ('it_mara[1]') to <fs_mara>        doesn´t work

Anyone an idea?