diff --git a/addons/purchase/purchase.py b/addons/purchase/purchase.py
index d7ddc39938f..a3135935045 100644
--- a/addons/purchase/purchase.py
+++ b/addons/purchase/purchase.py
@@ -776,11 +776,10 @@ class purchase_order_line(osv.osv):
             date_order = fields.date.context_today(cr,uid,context=context)
 
         qty = qty or 1.0
-        main_supplierinfo = False
+        supplierinfo = False
         supplierinfo_ids = product_supplierinfo.search(cr, uid, [('name','=',partner_id),('product_id','=',product.id)])
-
-        for supplierinfo in product_supplierinfo.browse(cr, uid, supplierinfo_ids, context=context):
-            main_supplierinfo = supplierinfo
+        if supplierinfo_ids:
+            supplierinfo = product_supplierinfo.browse(cr, uid, supplierinfo_ids[0], context=context)
             if supplierinfo.product_uom.id != uom_id:
                 res['warning'] = {'title': _('Warning'), 'message': _('The selected supplier only sells this product by %s') % supplierinfo.product_uom.name }
             min_qty = product_uom._compute_qty(cr, uid, supplierinfo.product_uom.id, supplierinfo.min_qty, to_uom_id=uom_id)
@@ -788,7 +787,7 @@ class purchase_order_line(osv.osv):
                 res['warning'] = {'title': _('Warning'), 'message': _('The selected supplier has a minimal quantity set to %s %s, you should not purchase less.') % (supplierinfo.min_qty, supplierinfo.product_uom.name)}
                 qty = min_qty
 
-        dt = self._get_date_planned(cr, uid, main_supplierinfo, date_order, context=context).strftime(DEFAULT_SERVER_DATETIME_FORMAT)
+        dt = self._get_date_planned(cr, uid, supplierinfo, date_order, context=context).strftime(DEFAULT_SERVER_DATETIME_FORMAT)
 
         res['value'].update({'date_planned': date_planned or dt, 'product_qty': qty})