Question

A cross between two pea plants tall with axial flowers and dwarf with terminal flowers produced offsprings tall with axial flowers and tall with terminal flowers in the ratio 1 : 1. What will be the genotype of parents?

• A. TTAa $\times$ ttaa
• B. TtAa $\times$ ttaa
• C. TtAA $\times$ ttaa
• D. TTAA $\times$ ttaa

Answer 1

The correct option is A TTAa $\times$ ttaa

The alleles for tallness (T) and axial flower (A) are dominant over that of dwarfism (t) and terminal flower (a) respectively. Since recessive traits are exhibited in homozygous genotypes only, the genotype of a dwarf parent with the terminal flower is "ttaa". To have both axial and terminal flowers in the progeny, the dominant parent should be heterozygous to allow the expression of a recessive allele in the next generation. This makes the genotype of tall plant with axial flower "TTAa".

So, the correct answer is option A.