In a cross between a pure tall pea plant with yellow pod and a pure short plant with green pod, how many double recessive plants would you expect in F₂ generation?

Step-by-step solution

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 F₁ generation will have the genotype TtGg , which corresponds to tall plants with green pods. Upon selfing the F₁ generation ( TtGg TtGg ), the F₂ generation is produced. The phenotypic ratio of the F₂ generation in a dihybrid cross is 9:3:3:1 , which represents: 9 Tal