diff --git a/poly/models.py b/poly/models.py
index c91f17a..c833644 100644
--- a/poly/models.py
+++ b/poly/models.py
@@ -63,6 +63,7 @@ class ModelWithMyManager(ShowFieldsAndTypes, ModelA):
 
 class MROBase1(PolymorphicModel):
     objects = MyManager()
+    field1 = models.CharField(max_length=10) # needed as MyManager uses it
 class MROBase2(MROBase1):  
     pass # Django vanilla inheritance does not inherit MyManager as _default_manager here
 class MROBase3(models.Model):