Question

The genotype of a plant showing the dominant phenotype can be determined by
a. Pedigree analysis
b. Back cross
c. Test cross
d. Dihybrid cross

Answer 1

In cases of the plants having the dominant phenotype can be determined by the test cross, the test cross was first discovered by George Mendel, it is used to determine the whether the individual exhibiting the dominant type is homozygous or heterozygous for the same trait.

Complete answer:
Test cross was discovered by George Mendel, it was mainly used to determine what alleles or genes are present in the genotype.
It is used to determine whether the organism with dominant trait is homozygous or heterozygous for a specific allele.
In test cross usually the organism with dominant trait is crossed with the recessive trait, if the offsprings which are produced is recessive type, then one can say the genotype is heterozygous, if the all the offsprings are dominant type, then one can consider the genotype is homozygous dominant.
Pedigree analysis is mainly used to determine the trait of the individual, like what trait is usually inherited from one generation to another generation, and to determine that particular trait like colour, height, shape etc.
Back cross is nothing but crossing the hybrid offspring with one of its parents or with an individual which is genetically similar to the parent.
Dihybrid cross is nothing but a cross between two different genes which are different from the observed traits. The Hybrid cross can be easily accessed by Punnett square.

Note: From the above options one can easily identify each test 1. Pedigree analysis: to determine the trait of individual 2. Back cross is to cross the hybrid offspring with parent 3. Test cross is used to determine the genes present in genotype 4. Dihybrid cross is used to cross between two different traits or genes.