Question

Assertion: Alloploidy has led to the evolution of many crop plants.
Reason: Alloploidy leads to the pairing of homologous chromosomes resulting in fertile hybrids.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.

Answer 1

Hint: Alloploidy also known as allopolyploidy is a type of Polyploidy. Polyploidy refers to the presence of more than two sets of chromosomes in any species. Polyploidy occurs due to the failure of cytokinesis after the telophase stage due to which a whole set of chromosomes increases.

Complete answer:
The Assertion statement given to us is that the Alloploidy has led to the evolution of many crop plants –
This statement is correct. The phenomenon of polyploidy occurs in plants only as in animals it causes sterility. Alloploidy is the type of polyploidy in which the different sets of chromosomes are derived from different species. It has caused the development and evolution of various species of crop plants. Several artificial hybrids are created by treating them with colchicine to induce polyploidy and the required characteristics.
The Reason statement given to us is that the Alloploidy leads to the pairing of homologous chromosomes resulting in fertile hybrids –
This statement is correct. During alloploidy, the homologous chromosomes from the fertile hybrids combine to cause polyploidy. The sterile plants cannot produce gametes. However, the fertile plants are from different species. Thus, based on the above information we can conclude that both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
Hence, the correct answer is option (A).

Note: Polyploidy is a type of Euploidy, which is further a type of Genomatic mutation. During euploidy, the change in the chromosomal numbers leads to the increase of the chromosomes in the multiples of the basic haploid sets.