The round and pretty pea is Iromi! The pea with a lot of wrinkles is Shiwao!

Yes. Iromi has a gene which makes a round shape and Shiwao has a gene which makes wrinkles, so such characteristics are appearing.

Of course, Iromi's gene is dominant, and Shiwao's gene is recessive .

The gene is not excellent just because it is dominant, and the gene is not inferior just because it is recessive.

Let’s say Iromi’s gene is A, and Shiwao’s gene is a. This is a cross of two pure lines of one allele.

Gamete A, which is one of the gametes AA of Iromi, and gamete a, which is one of the gametes aa of Shiwao, combine, and a child (Aa) is born.
At that time, from such a combination all the children born have gene Aa and the children become round like Iromi, because gene A is dominant to gene a.

There are characteristics that are easy for children to appear with and it is hard for children to appear with.