In a cross between a pure tall pea plant with yellow pod and a pure...

In pea plants, tallness (T$) is dominant over shortness (t$), and green pod colour (G$) is dominant over yellow pod colour (g$).

The cross is between a pure tall plant with yellow pods (TTgg$) and a pure short plant with green pods (ttGG$).

The $F_1$ generation will have the genotype $TtGg$, which corresponds to tall plants with green pods.

Upon selfing the $F_1$ generation (TtGg \times TtGg$), the$F_2$generation is produced.<br><br>The phenotypic ratio of the$F_2$generation in a dihybrid cross is 9:3:3:1$, which represents:
$9$ Tall, Green pods
$3$ Tall, Yellow pods
$3$ Short, Green pods
$1$ Short, Yellow pod

The double recessive phenotype is the short plant with yellow pods (ttgg$).<br><br>Out of 16$ possible combinations in the $F_2$ generation, only $1$ plant is double recessive.

Answer: One