According to RadGrid data binding documentation, the DataSource property accepts instances of the following types:
DataSet  
DataTable 
DataView  
- Array of 
DataRow  
- Any object collection that implements these interfaces:
  
  
IListSource 
IList 
IEnumerable 
ICustomTypeDescriptor 
 
Based from reference inspection, SqlDataReader doesn't supported because it doesn't implement those interfaces mentioned above, hence NotSupportedException has thrown when binding SqlDataReader contents into DataSource property directly.
As a workaround, you may create new DataTable instance and fill its contents from SqlDataReader like this:
var dt = new DataTable();
using (SqlConnection con = new SqlConnection(mydatasource))
{
    con.Open();
    SqlCommand cmd = new SqlCommand("select SRID, Name, Result from EditBatchResultsView where SRID = " + drpSRID.Text, con);
    SqlDataReader reader = cmd.ExecuteReader();
    // fill DataTable contents
    dt.Load(reader);
    // assign DataTable as data source instead
    radGridView1.DataSource = dt;
}
// DataBind goes here
Note:
The string concatenation to build SQL query may prone to SQL injection. Using parameters when passing server control value to SQL query is more recommended way:
var dt = new DataTable();
using (SqlConnection con = new SqlConnection(mydatasource))
{
    con.Open();
    SqlCommand cmd = new SqlCommand("select SRID, Name, Result from EditBatchResultsView where SRID = @SRID", con);
    cmd.Parameters.Add("@SRID", SqlDbType.VarChar).Value = drpSRID.Text;
    SqlDataReader reader = cmd.ExecuteReader();
    // fill DataTable contents
    dt.Load(reader);
    // assign DataTable as data source instead
    radGridView1.DataSource = dt;
}
Related issue:
Populate data table from data reader