PHP - enviar registro a mysql, seleccionando un campo en un combobox

<?php

error_reporting(0);

session_start();

mysql_connect("localhost","root","") or die("No se puede conectar");

mysql_select_db("acapane") or die ("No se ha podido seleccionar la Base de Datos");

//Recuperacion de las variables convertidas en sesiones

$edo=$_SESSION['edo2']=@$_REQUEST['edo'];

$str = $edo;

$edo =explode('|', $str, 2);

$muni=$_SESSION['muni2']=@$_REQUEST['muni'];

$str = $muni;

$muni =explode('|', $str, 2);

?>

<form name="form1" >

<?php

//QUERY COMBO 1

$query="select * from seccion";

$res=mysql_query($query);

?>

<p align=center>Seccion:

<select name="edo" onchange="this.form.submit()" >

  <?php if($edo[0]!=''){  ?>

    <option value="<?php echo $edo[0]."|".$edo[1]; ?>"><?php echo $edo[1]; ?></option>

  <?php   } else { ?>

    <option >Elige</option><?php }?>

  <?php while($row=mysql_fetch_array($res))

    {?>

  <option value="<?php echo $row['id_seccion']."|".$row['nombre seccion']?>"> <?php echo htmlentities($row['nombre seccion']);?></option>

  <?php

  }

  ?>

</select>

</p>

<p align=center>

<?php

//QUERY COMBO 2

$query2="select * from estudiante WHERE id_seccion=$edo[0]";

$res2=mysql_query($query2);

?>

Especifica estudiante

<select name="muni"  onchange="this.form.submit()">

     <?php if($muni[0]!=''){  ?>

    <option value="<?php echo $muni[0]."|".$muni[1]; ?>"><?php echo $muni[1]; ?></option><?php  } else { ?>

    <option > Elige</option><?php }?>

        <?php while($row2=mysql_fetch_array($res2))

        {

    ?>

        <option value="<?php echo $row2['id_estudiante']."|".$row2['nombre']?>"><?php echo htmlentities($row2['nombre']);?></option>

        <?php

    }

    ?>

</select>

</p>

<p>

<!--<input type="submit" name="enviar" value="Enviar" />--><br /><br />

</p>

</form>

<p align=center> <span style="color: red;" <strong>

  seccion: <?php echo $edo[1];?><br />

  estudiante:  <?php echo $muni[1];?><br/>

</p>

</div>

<script src="SpryAssets/SpryValidationTextField.js" type="text/javascript"></script>

<link href="SpryAssets/SpryValidationTextField.css" rel="stylesheet" type="text/css" />

<link href="SpryAssets/SpryValidationTextarea.css" rel="stylesheet" type="text/css" />

<script src="SpryAssets/SpryValidationTextarea.js" type="text/javascript"></script>

<form action="<?php echo $editFormAction; ?>" method="post" name="form1" id="form1">

  <table align="center">

     <tr valign="baseline">

      <td height="38" align="right" nowrap="nowrap">nota:</td>

      <td><input type="text" name="Pais" value="" size="32" /></td>

    </tr>

       <tr valign="baseline">

      <td height="108" align="right" valign="middle" nowrap="nowrap">comentarios:</td>

      <td><span id="sprytextarea1">

        <textarea name="Comentario" cols="32" rows="5"></textarea>

      <span class="textareaRequiredMsg">A value is required.</span></span></td>

    </tr>

    <tr valign="baseline">

      <td nowrap="nowrap" align="right">&nbsp;</td>

      <td align="center"><input type="submit" value="Enviar" /></td>

    </tr>

  </table>

  <input type="hidden" name="MM_insert" value="form1" />

</form>

<p>&nbsp;</p>

<script type="text/javascript">

var sprytextfield1 = new Spry.Widget.ValidationTextField("sprytextfield1");

var sprytextfield2 = new Spry.Widget.ValidationTextField("sprytextfield2", "email");

var sprytextarea1 = new Spry.Widget.ValidationTextarea("sprytextarea1");

</script>