radiobutton list only store null value in database

Question

I am using radiobutton list with 3 list item, after select one list item its only take null value in database 

<asp:RadioButtonList ID="rdltype" runat="server" DataTextField="Type" DataValueField="Type" RepeatDirection="Horizontal" CssClass="spaced"
                Style="font-weight: 700" >
                <asp:ListItem> ls1</asp:ListItem>
                <asp:ListItem>ls2</asp:ListItem>
                <asp:ListItem>ls3</asp:ListItem>
                
            </asp:RadioButtonList>

 

cmd.Parameters.AddWithValue("@FarmerType", rdltype.SelectedItem.Text);