What is back cross ? Explain with suitable example.

OR

Explain back cross with its significance.

i) Back cross :

a) A cross between an F1 offspring with either of its parents is called a back cross

b) When an F1 offspring is crossed with its dominant parent all the F2 offspring show the dominant character.

For example :

Significance of back cross :

a) The back cross is of great significance as it is one of the rapid methods of improving the variety of a crop.

b) Plant breeders introduce desirable characters in crop plants with the help of a back cross.

c) Back cross is frequently used in hybridization experiments.

Test cross is a back cross but back cross is not necessarily a test cross:

Test cross :

a) A test cross is conducted to determine the unknown genotype of the individual.

b) It is crossing of F1 hybrid only with recessive parent.

c) It is used for checking the correctness of Mendel's Law of segregation and law of independent assortment.

d) Test cross is always a back cross.

Back cross :

a) Back cross is used by the animal and plant breeders to rapidly improve a variety (breed).

b) It is a crossing of F1 with any one of the parents.

c) It is used as a method for obtaining a desirable trait in a pure homozygous condition

d) Back cross may not be a test cross since it may involve a cross of F1 hybrid with homozygous dominant parent also.