Change background texture from an array of textures held in a singleton

I've created a singleton of an ApplicationModel class to hold various info that will be used across scenes. I have created an array of Textures for possible different backgrounds that I would like to select at random. Problem I am having is when I select a Texture at random and save that to a variable in the singleton, I keep getting a null reference when I try to apply that texture to my background plane.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class ApplicationModel : MonoBehaviour
5. {
6.     public static ApplicationModel appModel;
7.    
8.     public Texture[] backgroundTextures;
9.     public Texture _backgroundTexture;
10.    
11.     void Start()
12.     {
13.         _backgroundTexture = backgroundTextures[Random.Range(0, backgroundTextures.Length)];
14.     }
15. }

Then when I try to reference _backgroundTexture on my background plane, it gives me a null reference.

Code (CSharp):

1. using UnityEngine;
2. using System.Collections;
3.  
4. public class BackgroundController : MonoBehaviour
5. {  
6.     void Start ()
7.     {
8.         //this.GetComponent<Renderer>().material.mainTexture = ApplicationModel.appModel._backgroundTexture;        // DOES NOT WORK      
9.  
10.         this.GetComponent<Renderer>().material.mainTexture = ApplicationModel.appModel.backgroundTextures[Random.Range(0, ApplicationModel.appModel.backgroundTextures.Length)];    // WORKS      
11.     }
12. }

It works if I reference the Texture array with a random index, but does not work when I reference the Texture variable I set in Start().

How can I set up a variable inside my ApplicationModel to hold a single Texture from my Textures array that I can use throughout my scenes? I have gotten the above to work by creating a random index and instead of referencing the random Texture, I reference the Textures array at the random index. Is there a way to set the Texture variable that I can reference vs using an index?

Thank you.

 

Not sure why this worked, but I used gameObject.GetComponent... vs this.GetComponent... and all seems to be working.