The pea which is round and yellow is Iromi! I have a gene that makes one round and yellow. Both genes are dominant genes!

I am green and have a lot of wrinkles. I have a gene that makes one wrinkled and green. Both genes are recessive genes....

This is a cross of Iromi, who has the characteristics (AABB) which are round and yellow, and Shiwao who has the characteristics (aabb) which are wrinkled and green.

AB of Iromi and ab of Shiwao combine, so all children have AaBb.
Because gene A is dominant to gene a, and gene B is dominant to gene b, the children have the characteristics of round and yellow.
Next, the children having a gene AaBb which was born cross each other.
There are four kinds of gametes born from AaBb, AB,Ab,aB,ab.
Each gamete is united, and we get the results like table 3.
Gene A is dominant to gene a, and gene B is dominant to gene b, so there are nine children who have the characteristics round and yellow, three with the characteristics round and green, three with the characteristics of wrinkled and yellow, and one with the characteristics of wrinkled and green.
If I display ratio of them, It becomes like this,

round : wrinkled = 12 : 4 = 3 : 1

Yellow : Green = 3 : 1.

The characteristics of yellow, green, round and wrinkled remain unaffected by other characteristics.