Dihybrid Cross

In dihybrid cross, when F1 plants (RrYy) are self hybridised, 12 yellow and 4 green seeds are produced. Therefore the ratio of segregation of yellow and green in F2 is 3:1

Step 1: Understanding the Concept:
In a dihybrid cross, we track two pairs of contrasting traits. However, according to Mendel's Law of Independent Assortment, the inheritance of one pair of characters is independent of the other. This means we can analyze each trait (seed color and seed shape) as a separate monohybrid cross.
Step 2: Detailed Explanation:
1. The genotype is . Selfing this gives . 2. To find the ratio for yellow vs. green seeds, we only look at the part of the cross. 3. A cross of results in: - (Yellow) - (Yellow) - (Yellow) - (Green) 4. Counting the phenotypes, we see 3 Yellow seeds for every 1 Green seed. 5. Even though the overall dihybrid phenotypic ratio is 9:3:3:1, if we isolate just one trait (seed color), it still follows the monohybrid segregation ratio of 3:1.
Step 3: Final Answer
The ratio of segregation of yellow and green in is 3:1.