Question

A gardener wants to breed tulips with specific characteristics.

She knows that the trait of red flowers is governed by the allele R(RR and
Rr) and the trait of white flowers is governed by the allele r (rr).
The gardener has a red tulip with an uncertain genetic makeup. She crosses
it with a white tulip (rr) and gets a generation in which half of the plants
have red flowers and half have white flowers.
?
a
Rr Rr
rr
rr
What does this ratio of offspring tell her about the genotype of the red tulip parent?
The red tulip parent is homozygous for red flowers
The red tulip parent is heterozygous for red flowers
The red tulip parent is homozygous for white flowers
The red tulip parent has incomplete dominance

Answer 1

The red tulip parent is heterozygous for red flowers, Option 2.

The observed ratio of offspring (half red and half white) suggests that the genotype of the red tulip parent is likely heterozygous for red flowers (Rr).

In Mendelian genetics, when a cross between a homozygous dominant (RR) and a homozygous recessive (rr) individual results in a 1:1 ratio of phenotypes in the offspring, it indicates that the dominant trait is likely heterozygous.

Therefore, the most plausible explanation is that the red tulip parent carries one dominant allele for red flowers (R) and one recessive allele for white flowers (r), making its genotype heterozygous (Rr).