key => value,value,value

##</code><code>##

my %hash = (
   key => [ value, value, value ],
   ...
);

##</code><code>##

use Data::Dumper qw/Dumper/;

my %hash = ();

while( <DATA> ){
    chomp;

    my ($k,$v) = split /\s*:\s*/;

    push @{ $hash{ $k } } , $v
}

print Dumper( \%hash );
__DATA__
green : apple
yellow: banana
green : kiwi
red   : strawberry
green : mango
yellow: lemon