To understand the generation outcomes in pea plants with yellow and green seeds, let’s follow Mendel’s method of crossing two true-breeding parents with opposite traits. Here is a step-by-step breakdown:
1. P Generation (Parental Generation):
- These are the true-breeding parent plants.
- If we assume that yellow seeds (Y) are dominant and green seeds (y) are recessive, one parent is homozygous dominant (YY) and the other is homozygous recessive (yy).
- Crossing YY (yellow) x yy (green) will result in all offspring being heterozygous (Yy).
2. Result:
- The P generation has all yellow seeds (True).
- The P generation has all green seeds (False).
- The P generation has yellow and green seeds (False).
3. F1 Generation (First Filial Generation):
- The F1 generation are the offspring from the P generation.
- All plants in the F1 generation are heterozygous (Yy), showing the dominant yellow seed trait.
4. Result:
- The F1 generation has yellow and green seeds (False).
- The F1 generation has all yellow seeds (True).
5. F2 Generation (Second Filial Generation):
- The F2 generation is obtained by self-pollinating the F1 plants (Yy x Yy).
- Crossing these heterozygous F1 individuals (Yy) will result in a phenotypic ratio of 3:1 (yellow to green) and a genotypic ratio of 1:2:1 (YY:Yy:yy).
6. Result:
- The F2 generation has all green seeds (False).
- The F2 generation has yellow and green seeds (True).
So, the comprehensive analysis of each generation is as follows:
- The P generation has all yellow seeds. (True)
- The P generation has all green seeds. (False)
- The P generation has yellow and green seeds. (False)
- The F1 generation has yellow and green seeds. (False)
- The F1 generation has all yellow seeds. (True)
- The F2 generation has all green seeds. (False)
- The F2 generation has yellow and green seeds. (True)
These statements summarize the expected results from Mendel’s classic genetic experiment with pea plants, focusing on the dominance of yellow seed color over green seed color.
