Get DropDownList selected value in Controllers in ASP.Net MVC

How to find selected dropdownlist value during post method without javascript jquery

        <div class="form-group">
            @Html.LabelFor(model => model.Org_Name, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">
                @Html.EditorFor(model => model.Org_Name, new { htmlAttributes = new { @class = "form-control" } })
                @Html.ValidationMessageFor(model => model.Org_Name, "", new { @class = "text-danger" })
            </div>
        </div>

        <div class="form-group">
            @Html.LabelFor(model => model.State, htmlAttributes: new { @class = "control-label col-md-2" })
            <div class="col-md-10">

                @Html.DropDownListFor(model => model.State, (IEnumerable<SelectListItem>)ViewBag.States, new { @class = "form-control",@id="ddrstate" })
                @Html.ValidationMessageFor(model => model.State, "", new { @class = "text-danger" })

            </div>
        </div>

            var stat = db.States.ToList();
            //Assigning generic list to ViewBag
            List<SelectListItem> Statlist = new List<SelectListItem>();
            foreach (State item in stat)
            {
                Statlist.Add(new SelectListItem
                {
                    Text = item.State1,
                    Value = item.State_id.ToString()
                });

            }
            ViewBag.States = Statlist;
            return View();

on post method

public ActionResult SignUp(orgn_detail orgt)
{
    organisation org = new organisation();
    org.Org_Name = orgt.Org_Name;
    org.State = orgt.State.ToString();//not able to find selected state value here?????
}