F 2 ratio is 9:3:3:1=> I.e YR: YW: GR: GW. it means
YR= 3×YW= 3× 90 = 270

In a dihybrid cross, two different traits are considered simultaneously to understand the inheritance pattern. In this case, we are considering the color (yellow or green) and shape (wrinkled or round) of seeds in a garden pea plant.


To begin with, let's denote the traits:
- Yellow seeds: Y (dominant)
- Green seeds: y (recessive)
- Round seeds: R (dominant)
- Wrinkled seeds: r (recessive)

The parental generation or P generation consists of two plants: one with yellow round seeds (YYRR) and the other with green wrinkled seeds (yyrr). Since both traits are dominant in the parental plants, they are homozygous for both traits.


When the P generation plants are cross-fertilized, the resulting offspring are known as the F1 generation. In this case, all the F1 generation plants will have yellow round seeds (YyRr). This is because the dominant traits (Y and R) mask the recessive traits (y and r).


To understand the possible combinations of traits in the F2 generation, we need to determine the gametes produced by the F1 plants. Each F1 plant will produce four types of gametes: YR, Yr, yR, and yr. These gametes are formed through the process of independent assortment, where the alleles for each trait separate randomly during gamete formation.


When the gametes from the F1 plants combine, the resulting F2 generation will exhibit various combinations of traits. Let's consider the possible combinations for each trait:

1. Yellow seeds (Y or y):
- YY: 1/4 probability
- Yy: 2/4 probability
- yy: 1/4 probability

2. Round seeds (R or r):
- RR: 1/4 probability
- Rr: 2/4 probability
- rr: 1/4 probability


To find out the number of plants in the F2 generation that will have yellow round seeds, we need to determine the probability of each combination:

Probability of yellow seeds = (Probability of YY + Probability of Yy) = (1/4 + 2/4) = 3/4
Probability of round seeds = (Probability of RR + Probability of Rr) = (1/4 + 2/4) = 3/4

To calculate the number of plants, we multiply the total number of plants obtained in the F2 generation (90) by the probabilities:

Number of plants with yellow round seeds = (Probability of yellow seeds) * (Probability of round seeds) * (Total number of plants)
= (3/4) * (3/4) * (90)
= 2025/16
≈ 126.56

Therefore, approximately 127 plants in the F2 generation will have yellow round seeds.


Through a dihybrid cross in garden peas, we