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Sahil performed an experiment to study the inheritance pattern of genes. He crossed tall pea plants (TT) with short pea plants (tt) and obtained all tall plants in F1 generation.
a. What will be set of genes present in the F1 generation?
Ans
In our case
Dominant trait is tallness which is represented by TT
Recessive trait is dwarfness wbich is represented by tt
On crossing of dominant trait with dwarf trait, following happens
TT* tt =Tt
hence, Genes present in F1 Generation is Tt
b. Give reason why only tall plants are observed in F1 progeny.
According to Mendels Law of Monohybrid Inheritance and Law of Segregation
If single pair of contrasting characterstics were cross bred by self pollination
In F1 Generation, plants with dominant traits are produced
Dominant traits is tallness which are produced in our case in F1 Generation
c. When F1 plants were self - pollinated, a total of 800 plants were produced.
How many of these would be tall, medium height or short plants? Give the genotype of F 2 generation.
In F2 Genration, different traits are obtained in the ratio of 3:1
| Trait | Ratio | No of Seeds |
| Tall | 3 | 3/4*800=600 |
| DWARF | 1 | 2/4*800=200 |
| Total | 4 | 800 |
Hence out of 800 plants produced,600 will be tall plants and 200 will be dwarf plants
OR
When F1 plants were cross - pollinated with plants having tt genes, a total of 800 plants were produced. How many of these would be tall, medium height or short plants? Give the genotype of F2 generation.
Answer
We have learnt in Part A that
F1 Plants are represented by Tt
They are cross pollinated with plants having tt genes
Following happens
Hence, in this case , 2 Tt and 2 tt are produced
Ratio is 2"2=1"1
Hence out of 800 plants produced,
400 will be TT
400 wlll be Tt
