Question

Question :
Work out a cross between a homozygous tall pea plant with green pods and a homozygous dwarf pea plant with yellow pods.

(i) State the phenotype and genotype of F1-generation.
(ii) Predict the phenotypic ratio of F2-generation using a Punnett square.
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Answer 1

Question :

Work out a cross between a homozygous tall pea plant with green pods and a homozygous dwarf pea plant with yellow pods.

(i) State the phenotype and genotype of F1-generation.

(ii) Predict the phenotypic ratio of F2-generation using a Punnett square.

Answer:−

Homozygous : An organism organism having two identical alleles of a particular gene.

Heterozygous : An organism that has two different alleles of a particular gene.

Now, we have a homozygous tall plant with green pods and a homozygous dwarf plant with yellow pods.

Here, we know tallest is dominant gene whereas recessive gene is the dwarfness.

And also that yellow pods are dominant whereas greenish pods are recessive.

So we obtain two plants with genes as following :-

One is : TTyy

Other is : ttYY

(i) The cross to obtain the first generation is the first photo attached.

In the first filial generation, the phenotype will be tall pea plant with yellow pods.

The genotype will be heterozygous with both the alleles of both the genes. It is : TtYy.

(ii) The punnett square for the second filial generation is given in the second photo attached.

Now, if we observe the phenotype of all the the progenies, we we will observe that :

Tall plant with yellow pods are in the number of 9.

Tall plant with green pods are in the number of 3.

Short plants with yellow pods are in the number of 3.

Short plants with green pots are in the number of 1.

So, the ratio is 9:3:3:1.