ArgumentException when calling Expression.GreaterThanOrEqual via Expression.Call

I get different behaviours when calling Expression.GreaterThanOrEqual dynamically or directly.

using System;
using System.Linq.Expressions;
using System.Reflection;

namespace ExpressionExample
{
    class Program
    {
        static void Main(string[] args)
        {
            // Build expression head.
            ParameterExpression param = Expression.Parameter(typeof(MyObj), "x");
            MemberExpression property = Expression.Property(param, "MyProperty");

            int value = 1;

            // Build expression body.
            MethodInfo greaterThanOrEqual = typeof(Expression)
                .GetMethod("GreaterThanOrEqual",
                    new[] { typeof(Expression), typeof(Expression) });

            Expression valueExpr = Expression.Convert(Expression.Constant(value),
                property.Type);

            // Dynamic Call
            //var expressionBody = Expression.Call(null, greaterThanOrEqual, property,
                  valueExpr);
            // Direct Call
            var expressionBody = Expression.GreaterThanOrEqual(property, valueExpr);

            // Make Lambda.
            Expression.Lambda<Func<MyObj, bool>>(expressionBody, param);
        }
    }

    class MyObj
    {
        public int MyProperty { get; set; }
    }
}

I took the code out of context for simplicity reasons. The Lambda at the end is later used within a where method of a Queryable. The direct call works fine and gives expected results. The dynamic call however throws a System.ArgumentException saying that System.Int32cannot be used as a parameter for the BinaryExpression GreaterThanOrEqual. That's actually the reason why I convert the value previously, which is also necessary for the direct call.

What's the difference here? How could I get the dynamic call to work?