How can i set a default value for a dependency property of type derived from dependencyobject

I am new to WPF and this is my first post. I have created a class called 'Fruit' that descends from 'DependencyObject' and adds and extra property called 'Apple'. I have created a new custom control that includes a Dependency Property called 'MyFruit' of type 'Fruit'. My question is, how can i set the default value for the properties within 'MyFruit' object (i.e. the 'Apple' property? I would like to set this in XAML using the object.

public class Gauge : Control
{
    .
    .
    .

    //---------------------------------------------------------------------
    #region MyFruit Dependency Property

    public Fruit MyFruit
    {
        get { return (Fruit)GetValue(MyFruitProperty); }
        set { SetValue(MyFruitProperty, value); }
    }

    public static readonly DependencyProperty MyFruitProperty =
        DependencyProperty.Register("MyFruit", typeof(Fruit), typeof(CircularGauge), null);

    #endregion


} 


//-------------------------------------------------------------------------
#region Fruit class

public class Fruit : DependencyObject
{
    private int apple;

    public int Apple
    {
        get { return apple; }
        set { apple = value; }
    }

 }

#endregion