Give a genetic explanation for the following cross. When a tall pea plant with round seeds was crossed with a dwarf pea plant with wrinkled seeds then all the individual of F₁-populations was tall with round seeds. However selfing among F₁-population led to a 9: 3 3 : 1 phenotypic ratio.

F2 plants

Phenotypic ratio is =

Law of dominance:

When a plant with two pair of contrasting trait is crossed, one member of the pair is dominant and the other is recessive. In the given cross the trait which appears in F1 offspring are dominant. So, in this cross, tall and round are dominant whereas dwarf and wrinkled are recessive.

Law of Segregation: Allelic pairs separate or segregate during gamete formation and the paired condition is restored during fertilization.

Law of Independent Assortment: The plants with new combination are seen in F2 generation (Tall wrinkled) (Dwarf round) is only possible when the two gene pairs for height and seed shape (assort) independently of each other during gamete formation