F2 Tall Plants & Segregation — NEET Biology
📚 Practice ConceptMendel self-pollinated the F2 plants and found that dwarf F2 plants continued to generate dwarf plants in F3 and F4 generations. He concluded that the genotype of the dwarfs was homozygous – tt. What do you think he would have got had he self-pollinated a tall F2 plant?
Which of the following statements are correct regarding true-breeding lines in the context of Mendelian genetics? S1. A true-breeding line consistently shows stable trait inheritance and expression for several generations upon continuous self-pollination. S2. They are produced by repeatedly crossing individuals with different desirable characters. S3. Mendel used true-breeding lines to ensure that the parental generation exhibited homozygous traits. S4. True-breeding lines are unsuitable for hybridisation experiments because they lack genetic variation. S5. If a true-breeding tall pea plant (TT) is self-pollinated, all its progeny will exhibit the dwarf phenotype.
View solution & NCERT explanation
Correct answer: A — S1 and S3 only
The core concept is the definition and significance of true-breeding lines in Mendelian genetics. S1. NCERT states: 'A true-breeding line is one that, having undergone continuous self-pollination, shows the stable trait inheritance and expression for several generations.' So, S1 is correct. S2. True-breeding lines are typically established through continuous self-pollination, not cross-pollination of different individuals. Repeated self-pollination leads to homozygosity. So, S2 is NOT correct. S3. By using true-breeding lines (e.g., TT for tall, tt for dwarf), Mendel ensured that the parental plants were homozygous for the traits being studied, providing a clear starting point for crosses. So, S3 is correct. S4. True-breeding lines are essential for hybridisation experiments as they provide known, stable parental genotypes. So, S4 is NOT correct. S5. If a true-breeding tall pea plant (genotype TT) is self-pollinated, all its progeny will also be tall (TT), not dwarf. So, S5 is NOT correct. Therefore, only statements S1 and S3 are correct. The tested concept is the definition, formation, and utility of true-breeding lines in genetic studies.
What does NCERT say about Mendel self-pollinated F2 plants?
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Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.