          kwargs['read_only'] = kwargs.pop('read_only', self.read_only)
          super(RelatedField, self).__init__(*args, **kwargs)
  
      def initialize(self, parent, field_name):
          super(RelatedField, self).initialize(parent, field_name)
          if self.queryset is None and not self.read_only:
              try:
 
</s> remove         self.queryset = kwargs.pop('queryset', None)
 </s> add         queryset = kwargs.pop('queryset', None)
        if not self.required:
            self.empty_label = BLANK_CHOICE_DASH[0][1]

        self.queryset = queryset

          kwargs['read_only'] = kwargs.pop('read_only', self.read_only)
          super(RelatedField, self).__init__(*args, **kwargs)
  
        if not self.required:
            self.empty_label = BLANK_CHOICE_DASH[0][1]

        self.queryset = queryset

      def initialize(self, parent, field_name):
          super(RelatedField, self).initialize(parent, field_name)
          if self.queryset is None and not self.read_only:
              try:
keep keep add keep keep keep keep
 Display an empty label into related fields if it isn't required 
rest_framework/relations.py