#!/usr/bin/perl -w
use Data::Dumper;

my $data = '/Data/Table1.txt'; 
open INFILE, '<', $data or die "a!\n";

while(<INFILE>)
{
   chomp;
   my $line = $_;
   
   my $key = (split/\t/, $line)[0];
   push @{ $hash{$key} }, $line;
}

print Dumper(\%hash);