Question

Based on test cross principles, if a tall plant consistently produces dwarf offspring when crossed with homozygous dwarf plants, what is the tall plant's genotype?

Options

• Homozygous recessive (tt)

• The genotype cannot be determined from this information

• Heterozygous (Tt)

• Homozygous dominant (TT)

Answer 1

The appearance of dwarf (recessive) offspring when a tall plant is crossed with a homozygous dwarf plant indicates the tall plant carries the recessive allele. Therefore, the tall plant must be heterozygous (Tt), as Tt × tt produces both Tt (tall) and tt (dwarf) offspring.