Question

In breeding a new genetic variety of a crop by hybridization, superior recombinants are self-pollinated for several generations till they reach a state of
A. Uniformity
B. Heterozygosity
C. Homozygosity
D. Both (1) and (3)

Answer 1

Hint: In a hybridization process, two parents are selected with superior characters. The recombinants produced from their cross possess superior traits from both parents. This makes the recombinant more superior than parents. The self crossing of recombinants yields progeny having similar superior characters.

Complete answer: An artificial breeding is a practice of producing superior varieties of crops. Two individuals with desired characters are selected and crossed. Their cross results in the recombinant or hybrid progeny. The recombinants will get the superior desired characters of both of their parents. The recombinants are then self-crossed for several consecutive generations. This results in homozygosity or uniformity. Homozygosity is a synonym for uniformity and these terms are used interchangeably. Homozygosity means that all of the progeny contains two similar alleles for a particular gene. Means that each parent contributes one allele to the offspring and both these alleles show similar traits related to a gene. On reaching the state of uniformity segregation of desired traits will not occur in future generations. This ensures the stability of the genetic line and superior characters in the new crop.
Homozygosity can be explained by considering the example of a gene that controls the flower colour in the crop. Consider a flower having a red colour for which the gene is RR. Single R represents an individual allele. Now, both the alleles are similar in this gene and this is called homozygosity.
Hence, the right answer is option D.

Note: The homozygosity of a cell can be of two types. A homozygous recessive cell means it has both the alleles with a recessive trait for a gene. A homozygous dominant cell will have both the allele showing the dominant trait. Consecutive breeding allows for the desired traits to come together in a single generation.