Question

practice with probability
in plants, the gene for red flowers (r) is dominant over the gene for white flowers (r), and the gene
for plant height (t) is dominant over the gene for dwarfism (t).
a homozygous dominant red - flowered, tall plant (rrit) is crossed with a heterozygous red -
flowered, tall plant (rrtt).
use the results of the punnett squares below to answer the question.
what is the phenotypic frequency of tall, red flower
offspring (r_t_)?

Explanation:

Step1: Analyze flower color

The homozygous dominant red - flowered plant (RR) is crossed with a heterozygous red - flowered plant (Rr). From the Punnett square for flower color, all offspring have at least one dominant R allele. So the probability of red flowers (R_) is 1.

Step2: Analyze plant height

Assume the cross for height: homozygous dominant (TT) × heterozygous (Tt). The Punnett square for height:

	T	T
t	Tt	Tt

All offspring have at least one dominant T allele. So the probability of tall plants (T_) is 1.

Step3: Calculate the combined probability

Since flower color and plant height are independent traits, use the multiplication rule. The probability of R_T_ (tall, red - flowered) is \(P(R_T_)=P(R_)×P(T_)\)
\(P(R_T_)=1\times1 = 1\)

Answer:

1