make: g77: Command not found

Hello everyone. I am new to opensuse and I am encountering a problem while trying to install pftools (http://web.expasy.org/pftools/). According to the README file when i type
[size=3]
[size=2]make all[/size][/size]
**
I get the following error
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[size=2]g77 -O2 -init-local-zero -fno-automatic io.o gtop.f -o gtop
make: g77: Command not found
make: *** [gtop] Error 127[/size]

I checked in yast -> software management -> searching fortran  and get the following ticked (which means installed i guess) 

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[size=3][size=2]gcc-fortran
gcc-fortran 32bit
gcc-33fortran
gcc-33fortran -32bit
gcc46-fortran
gcc46-fortran-32bit
libg2c33
libg2c33-32bit
libgfortran46
libgfortran46 32bit
libquadmath46
libquadmath46 32bit
[/size][/size]**
gfortran is installed (am i right as it is in the ticked list?). but still am getting the above error. Can anyone please help me to sort out the error in order to install pftools? :frowning: