Inbreeding depression: Inbreeding exposes harmful recessive genes that are eliminated by selection.It also helps in accumulation of superior genes and elimination of less desirable genes.this approach, where there is selection at each step ,increases the productivity of inbred population.However,continued inbreeding, especially close breeding, usually reduces fertility and even productivity.This is called inbreeding depression.
Selection of superior males and superior females of the same breed: Selected sexes are followed to mate in pairs.Progeny obtained from such matings is evaluated, and superior animals are further selected.Selected individuals are again allowed to interbreed, and the selection is repeated on the progeny.
Advantage of interbreeding:
1.Inbreeding brings the homozygosity in the population so it helps in producing pure line of animals.
2. It helps in accumulation of superior genes and elimination of less desirable genes and hence increases the productivity of inbred population.