Dihybrid Cross with Heterozygous Traits — NEET Biology
📚 Practice ConceptWhen a cross in made between tall plant with yellow seeds (TtYy) and tall plant with green seed (Ttyy), what proportions of phenotype in the offspring could be expected to be (a) tall and green. (b) dwarf and green.
Which of the following statements regarding Mendel's experiments and laws of inheritance are correct? S1: Mendel studied seven pairs of contrasting traits in pea plants, including pod shape (inflated/constricted) and seed colour (yellow/green). S2: Leaf colour (red/green) and seed texture (rough/smooth) were among the specific traits investigated by Mendel in pea plants. S3: In a monohybrid cross between a true-breeding tall plant and a true-breeding dwarf plant, all F1 progeny express the dwarf phenotype, demonstrating the recessive nature of tallness. S4: The Law of Segregation states that during gamete formation, the alleles of a pair segregate from each other, ensuring each gamete receives only one allele with equal proportion. S5: A test cross involves crossing an organism showing a dominant phenotype (whose genotype is to be determined) with a heterozygous recessive parent. S6: Mendel's significant contribution included the application of statistical analysis and mathematical logic to biological problems, which was novel for his time.
View solution & NCERT explanation
Correct answer: C — S1, S4 and S6 only
Let's evaluate each statement: S1: This statement is correct. Table 4.1 in NCERT lists 'Pod shape: Inflated/constricted' and 'Seed colour: Yellow/green' as two of the seven contrasting traits studied by Mendel in pea plants. S2: This statement is incorrect. Mendel did not study leaf colour or leaf texture. The traits listed in Table 4.1 are stem height, flower colour, flower position, pod shape, pod colour, seed shape, and seed colour. S3: This statement is incorrect. In a monohybrid cross between a true-breeding tall plant (dominant) and a true-breeding dwarf plant (recessive), all F1 progeny are tall, not dwarf. This illustrates the Law of Dominance, where the dominant trait is expressed in the F1 generation. S4: This statement is correct. The Law of Segregation, or the First Law of Inheritance, states that during gamete formation, the two alleles of a pair segregate from each other such that each gamete receives only one of the two alleles with equal probability. S5: This statement is incorrect. A test cross is performed to determine the genotype of an organism showing a dominant phenotype by crossing it with the *recessive* parent (i.e., homozygous recessive), not a heterozygous recessive parent. S6: This statement is correct. Mendel was the first to apply statistical analysis and mathematical logic to problems in biology, which was a novel approach at that time and contributed to the credibility of his data. Therefore, statements S1, S4, and S6 are correct.
What does NCERT say about When cross made between?
Has this concept appeared in NEET?
Which chapter is this from?
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.