how to slice a texture2d in unity programmatically like i want to divide my texture in to two parts

Question

my input is texture2d which is 4 channel one so i have to divide the 2 parts of it kind of slicing how can??

i have tried it creating other mat and tex and copied till half of the texture

Mat slice = imageMat.submat(0,0,image.height, 330);
byte[] sliceData = new byte[(int)(slice.total() * slice.channels())];
slice.get(0,0,sliceData)

Texture2D fh = new Texture2D(slice.cols(), slice.rows(), 
TextureFormat.RGBA32, false);
Utils.matToTexture2D(slice, fh);

it is giving me an blank image with trasparent backgrond but not i want i just want to divide or slice an image programatically