Referring to http://social.msdn.microsoft.com/Forums/en/sharepointdevelopment/thread/b73dd31b-1ec9-4f44-8cb2-80b2f6796eb5
Does SharePoint 2010 create default groups when site collection is created pro grammatically ?
You can use SPWeb.CreateDefaultAssociatedGroups method on your root web to create default Owner and Visitors groups.
Sign up using Google
Sign up using Facebook
Sign up using Stack Exchange
3 years ago