Collection select default value

Bit of a conundrum, I’m trying to offer a user the opportunity to
update 3 drop down collection selects at once which is working fine my
only problem is I can’t seem to get the default value to display, I’ve
tried using :selected but that doesn’t seem to be working, my code
looks like:

In the view:


<%for assigned in @degree.assigneds%>

<%=text_field 'assigned', 'grade',"value" =>assigned.grade %>

Qualification ID
<%=collection_select('assigned', :qual_id, @quals,:id, :screen_qual,{},:selected=>assigned.qual_id)%>

In the controller

@degree.attributes = params[:degree]
@degree.assigneds.each { |assigned| assigned.attributes =
params[‘assigned’] }
if @degree.valid? && @degree.assigneds.all?(&:valid?)!
redirect_to :action => ‘show’, :id => @degree
render :action => ‘edit’

if I change the first variable in the collection select from
‘assigned’ to just :assigned then it does work but
then I can;t work out how to differentiate between the input from each
of the drop downs in the controller.

Any help would be much appreciated

still having absolutely no luck with this, anyone got any idea?