Question

in pea plants round pods dominate wrinkled pods. what would be the genotypic ratio of the offspring from a cross of a heterozygous round pod crossed with a wrinkled pod?
○ 3 hetero: 1 recessive
○ 1 hetero: 1 recessive
○ all hetero
○ 3 wrinkled : 1 round

Explanation:

Step1: Define Genotypes

Let \( R \) be dominant (round), \( r \) recessive (wrinkled). Heterozygous round: \( Rr \); wrinkled: \( rr \).

Step2: Set Up Punnett Square

	\( R \)	\( r \)
\( r \)	\( Rr \)	\( rr \)

Step3: Analyze Offspring Genotypes

Offspring: \( Rr, Rr, rr, rr \). Genotypes: 2 \( Rr \) (hetero), 2 \( rr \) (recessive)? Wait, no—wait, Punnett square has 4 cells. Wait, \( Rr \times rr \): gametes from \( Rr \) are \( R \) and \( r \); from \( rr \) are \( r \) and \( r \). So:

• \( R \times r = Rr \)
• \( r \times r = rr \)
• \( R \times r = Rr \)
• \( r \times r = rr \)

So two \( Rr \) (hetero) and two \( rr \) (recessive)? Wait, no, ratio is 2:2, which simplifies to 1:1. Wait, the options: "1 hetero: 1 recessive" (since 2:2 is 1:1 when simplified, or maybe I miscounted. Wait, \( Rr \) (hetero) and \( rr \) (recessive). So number of \( Rr \): 2, \( rr \): 2. So ratio 1:1 (1 hetero : 1 recessive, since 2/2 = 1, 2/2 = 1? Wait, maybe the problem considers "hetero" as \( Rr \) and "recessive" as \( rr \). So from the cross, 50% \( Rr \), 50% \( rr \), so ratio 1:1.

Answer:

B. 1 hetero: 1 recessive (assuming the option is labeled as such; in the options, the second one is "1 hetero: 1 recessive")