Avocado: Strange growth in the seed

The avocado root is growing quickly and is wrapping around the bottom of the container. Soon, it will need to be transplanted. (I say this every week, but I never get around to it.)

What bothered me this week was a significant growth of white nodules around the origin of the root and stem. You can see it in the picture. It looks like cottage cheese between the root and the stem.

If anyone knows what this is, whether it is normal or some sort of disease, a little help is much appreciated.