Given below two statements: one is labelled as assertion A and the other is labelled as Reason R
Assertion A: In F2 generation of a Mendelian cross, the traits seen in the progeny are identical to their parents.
Reason R: The progeny of the F2 generation in a Mendelian cross shows no blending of traits.
In the light of the above statements, choose the most appropriate answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Both A and R are correct and R is the correct explanation of A
Assertion A: In F2 generation of a Mendelian cross, the traits seen in the progeny are identical to their parents. — Correct. When Mendel crossed tall and dwarf pea plants, the F2 plants were either tall or dwarf, just like the two parents. None was of a height in between.
Reason R: The progeny of the F2 generation in a Mendelian cross shows no blending of traits. — Correct. The two factors of a trait stay separate and do not mix. The recessive trait hidden in F1 comes out unchanged in F2.
R explains A: because there is no blending, each F2 plant shows one of the parents’ traits in its original form.
NCERT Extract:
Inheritance of One Gene – “… Mendel then self-pollinated the tall F1 plants and to his surprise found that in the Filial2 generation some of the offspring were ‘dwarf ’; the character that was not seen in the F1 generation was now expressed. The proportion of plants that were dwarf were 1/4th of the F2 plants while 3/4th of the F2 plants were tall. The tall and dwarf traits were identical to their parental type and did not show any blending, that is all the offspring were either tall or dwarf, none were of in-between height (Figure 4.3).”
Figure 4.3 Diagrammatic representation of monohybrid cross