Question

A common test to find the genotype of a hybrid is
A. Crossing of one $F_2$ progeny with male parent
B. Crossing of one $F_2$ progeny with female parent
C. Studying the sexual behavior of $F_1$progenies.
D. Crossing of one $F_1$ progeny with recessive parent

Answer 1

Hint:Genotype refers to the genetic characteristics of the organism and helps us to reveal the alleles of an individual that are inherited in an individual from their parents. It helps us to encode the characteristics that are physically expressed (phenotype) in an organism such as hair color, height etc.

Complete Answer:
Mendel, known as the Father of Genetics, worked on the pea plant to discover the inheritance pattern of Gene into the individual from their parents. He did the cross between the two parents having contrasting characters. He found the results of their hybridization as the offspring in $F_1$ generation. Then he did the test cross in which he did the cross between one $F_1$ progeny with a recessive parent.

Additional information:The term genotype was coined by Wilhelm Johannsen in 1903. Genotype of an individual helps us to determine the genetic characteristics that are physically expressed in an individual(phenotype).
Genotype is used in various fields like for determination of blood groups, gene linked disease like haemophilia, colour blindness. Genotyping is the process of explaining the Genotype of an individual by the means of various assays like PCR(Polymerase chain reaction), RFLP(Restriction fragment length polymorphism) etc.
Genotype varies from individual to individual except identical twins because in identical twins, fertilization takes place between the same egg and the same sperm.

The correct option is D i.e. crossing of one $F_1$ progeny with recessive parent.

Note:Genotype can be of three types that are homozygous dominant(represented as TT for tall in pea plant), homozygous recessive(represented as tt for dwarf in pea plant) and heterozygous. Heterozygous is always dominant in nature.