Question

What is a test cross ? how can it decipher the hetrozygosity of a plant ?

Answer 1

Answer:

A test cross is a cross between F1 progeny and its homozygous recessive parent. This cross determines whether the dominant character is coming from the homozygous dominant genotype or heterozygous genotype (e.g. tallness coming from TT or Tt). When TT is crossed with tt, we obtain all Tt (tall) individuals in the F1 progeny, whereas when Tt is crossed with tt, we obtain Tt (tall) and tt (dwarf) individuals in the F2 progeny. Thus, a test cross can be used to determine the heterozygosity of the plant.

Answer 2

Answer:

If the progenies produced by a test cross show 50% dominant trait and 50% recessive trait, then the cross in which the genotype of an unknown dominant phenotype can be determined by crossing it with an individual homozygous recessive phenotype for that trait is called a test cross.

This cross determines whether the dominant character is coming from homozygous dominant genotype or heterozygous genotype (e.g., tallness coming from Tt) when Tt is crossed with tt, we obtain Tt (tall) individuals in the program.

Thus, this test can be used to determine the hetrozygosity of the plants.