Which of the following are true, caused due to Inbreeding?
A. Reduces fertility and productivity
B. Helps in accumulation of inferior genes
C. Helps to evolve a hybrid in any animal
D. Increases productivity inbreed population
E. Retention of less desirable genes
Choose the correct answer from the options given below
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → A and D only
Inbreeding is the mating of more closely related animals within the same breed for 4–6 generations. With selection at each step it brings good genes together. If it goes on too long, fertility and productivity fall: this fall is called inbreeding depression.
A. Reduces fertility and productivity — True. Continued close inbreeding brings harmful recessive genes together in the homozygous form. Fertility and yield then fall.
B. Helps in accumulation of inferior genes — False. Inbreeding exposes harmful recessive genes, and selection removes them. It helps to collect superior genes, not inferior ones.
C. Helps to evolve a hybrid in any animal — False. Inbreeding increases homozygosity, so it is used to evolve a pureline. A hybrid comes from crossing different breeds (cross-breeding) or species.
D. Increases productivity inbreed population — True. When selection is made at each step, inbreeding raises the productivity of the inbred population.
E. Retention of less desirable genes — False. Inbreeding with selection eliminates less desirable genes; it does not keep them.
Note: This question is from Chapter 9, Strategies for Enhancement in Food Production, of the pre-rationalised NCERT book. This chapter is not in the present NCERT book (2026-27). The extract below is from the pre-rationalised edition.
NCERT Extract (Pre-rationalised edition, Chapter 9, Strategies for Enhancement in Food Production):
Animal Breeding – “… Try to recollect the homozygous purelines developed by Mendel as discussed in Chapter 5. A similar strategy is used for developing purelines in cattle as was used in case of peas. Inbreeding increases homozygosity. Thus inbreeding is necessary if we want to evolve a pureline in any animal. Inbreeding exposes harmful recessive genes that are eliminated by selection. It also helps in accumulation of superior genes and elimination of less desirable genes. Therefore, this approach, where there is selection at each step, increases the productivity of inbred population. However, continued inbreeding, especially close inbreeding, usually reduces fertility and even productivity. This is called inbreeding depression.”