To reproduce:

public Form1()
{
    InitializeComponent();

    this.radDropDownList1.DropDownStyle = RadDropDownStyle.DropDownList;
    this.radDropDownList1.Text = "Select Name";
    string[] names = { "Ketan", "Leena", "Amar" };

    radDropDownList1.Items.AddRange(names);
}

private void button1_Click(object sender, EventArgs e)
{
    radDropDownList1.SelectedIndex = -1;
    radDropDownList1.Text = "Select Name";
}

1. Select any name from the drop down.
2. Click the button. The 'Text' is center justified.

Workaround: use RadDropDownStyle.DropDown and NullText instead of setting the Text property.

this.radDropDownList1.DropDownStyle = Telerik.WinControls.RadDropDownStyle.DropDown; 
this.radDropDownList1.NullText = "Select Name";