By default the Title of a SharePoint Team Site does not show the site inheritance (e.g. Root Site->Parent Site->Current Site will only show Current Site).
To show this inheritance, replace:
<SharePoint:SPLinkButton runat="server" NavigateUrl="~site/" id="onetidProjectPropertyTitle"><SharePoint:ProjectProperty Property="Title" runat="server" /></SharePoint:SPLinkButton>
With
<asp:SiteMapPath runat="server" SiteMapProviders="SPSiteMapProvider,SPXmlContentMapProvider" RenderCurrentNodeAsLink="false" NodeStyle-CssClass="breadcrumbNode" CurrentNodeStyle-CssClass="breadcrumbCurrentNode" RootNodeStyle-CssClass="breadcrumbRootNode" HideInteriorRootNodes="true" SkipLinkText=""/>
Source: http://sharepoint.stackexchange.com/questions/11480/breadcrumb-not-showing-parent-site
