Enregistrer le champs de type select???

Bonjour,
Dans la partie backoffice j'ai un formulaire où il existe un select

<?php

	$URLretour='Permis_liste.php';
	require("access.inc.php");
	require("../lib/db_connect.inc.php");
	require("../lib/util.php");
   
	
		$connexion=db_connexion();	
	mysql_query("set names utf8");
	if (!isset($_GET["Num"])) 
	{
		header("Location: " . $URLretour);
		exit();
	}
	$Num=$_GET["Num"];
	
	if ($Num!="-1") 
	{
		$resultat =mysql_query("SELECT * FROM permis where id=$Num");
		$Enreg=mysql_fetch_array($resultat);
	     $sujet=$Enreg["sujet"];
		$etat=$Enreg["etat"];
		
	}
?>
<form name="form1" method="post" action="Permis_EnregSaisie.php">
<table width="650" border="0" align="center" cellpadding="0" cellspacing="0" id="ListeAdm">
  <tr>
    <td align="left" class="Formulaire" style=" padding:20px">
		<div><span>Etat</span>
           <input type="radio" name="etat" value="1" style="background-color:#CCCCCC" <?php  if(@$etat==1) { echo "checked=checked";} ?> >
            &nbsp;<img src="img/encour.png" border="0" />&nbsp;&nbsp; 
            <input type="radio" name="etat" value="2" style="background-color:#CCCCCC"  <?php  if(@$etat==2) { echo "checked=checked";}  ?> />
            &nbsp;<img src="img/accepte.gif" border="0" />&nbsp;&nbsp; 
            <input type="radio" name="etat" value="3" style="background-color:#CCCCCC"  <?php  if(@$etat==3) { echo "checked=checked";}  ?> />&nbsp;<img src="img/refuse.png" border="0" />&nbsp;&nbsp;
		</div>
		<div><span>CIN</span> 
           <input name="CIN" type="text"  size="15" maxlength="150" value="<?php if($Num!='-1' ) { print $Enreg['CIN']; } ?>" >
	    </div>
		<div><span>Identifiant</span> 
           <input name="numeros_permis" type="text"  size="15" maxlength="150" value="<?php if($Num!='-1' ) { print $Enreg['numeros_permis']; } ?>" >
	    </div>
		  <div><span>Date du dépot</span> 
            <input name="date_depot" type="text"  size="15" maxlength="150" onblur="twValide_date(this,1950,2020,'jj/mm/aaaa')" value="<?php if($Num!='-1')  { print date2string($Enreg['date_depot']);} ?>" onchange="this.value" />
          </div>
		<div><span>Nom</span> 
           <input name="nom" type="text"  size="50" maxlength="150" value="<?php if($Num!='-1' ) { print $Enreg['nom']; } ?>" >
	    </div>
		<div><span>Prénom</span> 
           <input name="prenom" type="text"  size="50" maxlength="150" value="<?php if($Num!='-1' ) { print $Enreg['prenom']; } ?>" >
	    </div>
		<div><span>Adresse</span> 
           <input name="adresse" type="text"  size="50" maxlength="150" value="<?php if($Num!='-1' ) { print $Enreg['adresse']; } ?>" >
	    </div>
		
		<div><span>Sujet</span> 
		  <select name="sujet[]" size="1" style="width: 200px">
		   <option value="<?php print $Enreg['sujet']; ?>" >sujet1</option>
           <option value="<?php print  $Enreg['sujet'] ; ?>">sujet2</option>
</select>
 
  
		 
		
		
		 </div>

et dan la page Permis_EnregSaisie.php

<?php
    require("access.inc.php");
	require("../lib/db_connect.inc.php");
	require("../lib/util.php");
	

	$URLretour='Permis_liste.php';
	
	$cNum=$_POST["Num"];
	
	$connexion=db_connexion();
    mysql_query("set names utf8");

    $sujet=$_POST["sujet"];
	
	if (isset($_POST["Annul_x"])) 
	{
		header("Location: " . $URLretour);  
			
	}
	
	if (!isset($_POST["Annul_x"]) && isset($cNum)) 
	{
	   $etat=$_POST["etat"];
	
	   if (isset($_POST["CIN"])) 
		   $CIN=prepareChaine($_POST["CIN"]);
		else 
			$CIN=prepareChaine("");
	   
		if (isset($_POST["numeros_permis"])) 
		    $numeros_permis=prepareChaine($_POST["numeros_permis"]);
		else 
			$numeros_permis=prepareChaine("");
			
		 
		if (isset($_POST["nom"])) 
		    $nom=prepareChaine($_POST["nom"]);
		else 
			$nom=prepareChaine("");
			
		if (isset($_POST["prenom"])) 
		    $prenom=prepareChaine($_POST["prenom"]);
		else 
			$prenom=prepareChaine("");
		
		if (isset($_POST["adresse"])) 
		    $adresse=prepareChaine($_POST["adresse"]);
		else 
			$adresse=prepareChaine("");
			
		if (isset($_POST['date_depot'])) 
			$date_depot=string2date($_POST["date_depot"]);
		else 
		 	$date_depot=string2date("");
		
		if (isset($_POST['sujet'])) 
			$sujet=string2date($_POST["sujet"]);
		else 
		 	$sujet=string2date("");
	    
		
	

		if (isset($_POST["note"])) 
		    $note=prepareChaine($_POST["note"]);
		else 
			$note=prepareChaine("");
			

		if($cNum != "-1")	
		{
		
		
 				// on met  jour la fiche existante
			$ChainedeMAJ = "numeros_permis=$numeros_permis, nom = $nom ,prenom = $prenom , adresse= $adresse, date_depot= $date_depot,sujet=$sujet, etat= $etat, note= $note";
			
 // echo $ChainedeMAJ;
						//	print "UPDATE permis Set $ChainedeMAJ WHERE Num = $cNum"; die();
			mysql_query("UPDATE permis Set $ChainedeMAJ WHERE id = $cNum");
		}
		
		else 
		{
		
			$champs  = "numeros_permis ,nom ,prenom , adresse, date_depot,sujet, etat, note";
			$valeurs = "$numeros_permis ,$nom ,$prenom , $adresse, $date_depot,$sujet' $etat, $note";
			
			//print "INSERT INTO client ($champs) VALUES ($valeurs)" ; die();
			mysql_query("INSERT INTO permis ($champs) VALUES ($valeurs)");
			
		}
	}// fi if annuler &	
	

		header("Location: " . $URLretour);  
		

 	exit();

?>

le pb que dans la base l'enregistrement du champs sujet est -1
ni sujet1 ni sujet2 ?????
je ne comprend pa pkoi ???
aidezzzzzz moi pllllz
c urgennnnnnnnt