Describe Mendel's experiment on pea plants involving two different traits.

(N/A) cross between two plants that differ in two traits is called a dihybrid cross.
Mendel conducted experiments to study the inheritance of two traits simultaneously in pea plants. For example,he chose plants with yellow,round seeds and green,wrinkled seeds as parents.
The yellow color is dominant over the green color,and the round shape is dominant over the wrinkled shape.
Genetic symbols: $Y$ - dominant (yellow),$y$ - recessive (green); similarly,$R$ - round shape (dominant),$r$ - wrinkled shape (recessive). The genotype of the parents can be represented as $YYRR \times yyrr$.
In the $F_1$ generation,all plants are heterozygous $(RrYy)$ and show the dominant phenotype (round yellow). Upon self-pollination of $F_1$ plants,the $F_2$ generation is produced,which shows a phenotypic ratio of $9:3:3:1$.