Answer:
The genotype of the randomly chosen F1 parent plant is "Tt"
Step-by-step explanation:
Let "T" represents the allele for tall height characteristic of plant and "t" represents the allele for short height characteristic of plant.
Given -
Two phenotypically tall heterozygous pea plants are crossed to one another.
Genotype of tall heterozygous pea plants would be "Tt"
F1 Generation -
Tt * Tt
TT, Tt, Tt, tt
Now, it is given that a phenotypically tall F1 progeny plant is randomly chosen and mated to a phenotypically dwarf pea plant.
Genotype of phenotypically dwarf pea plant would be "tt"
Also, it is given that some of the F2 offspring from this mating are phenotypically dwarf this implies that progeny selected from F1 generation must have an allele for short height characteristics i.e "t"
Therefore,
in F2 generation cross will take between tt * Tt
thereby producing Tt, Tt, tt, tt
Therefore, the genotype of the randomly chosen F1 parent plant is "Tt"