Cant get the complete contour plot

Hi I am trying to implement this code but the problem is I can't get the complete contour plot. The center lines of the plot is missing .Can anyone please tell me what is wrong with the code

%means of two inpout matrices
MU1 = [1.5;3.5];
MU2=[5.5;7];
%covariance of two matrices
SIGMA1 =[1 0.7032;0.7032 1];
SIGMA2 = [1 0; 0 1];
mu = [MA MB];
sigma = cat(3,rho,[1 0;0 1]);
%mixing proportion
p = [0.2 0.8];
obj = gmdistribution(mu,sigma,p);
figure;
ezcontour(@(x,y)pdf(obj,[x y]),[-10 10],[-10 10]);

I would be really thankful if someone can reply to my query.

Thanks

Ben

[Image Analyst]

I fixed your formatting for you. Please read this so you can do it yourself next time: http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup

[Supreeth Subbaraya]

What is the value of the variable "rho"? And also does MA and MB in your code mean MU1 and MU2 respectively?