Reduce Draw call for Multiple GUI Textures with same Texture

I have multiple GUI Textures with same texture in my game. It results large number of DrawCalls . How to reduce DrawCalls using common textures ?

Example code

 using UnityEngine;
 using System.Collections;
  
 public class Example : MonoBehaviour 
 {

   public GUISkin MyGUISkin;

   void OnGUI()

     {

       GUI.Box ( new Rect ( Screen.width*0.1f,Screen.height*0.12f,Screen.width*0.49f,Screen.height * 0.58f),"",MyGUISkin.customStyles[1]);

       GUI.Box ( new Rect ( Screen.width*0.1f,Screen.height*0.22f,Screen.width *0.49f,Screen.height * 0.58f),"",MyGUISkin.customStyles[1]);

     }


  }