Question

The cross used to ascertain whether the plant is homozygous or heterozygous is
A. Hybrid cross
B. Reciprocal cross
C. Test cross
D. Monohybrid cross

Answer 1

This is a cross in which two parents are considered for cross having only one character. For example, in the monohybrid cross that was performed by Mendel, he considered the character as the height of the plant, where two traits were selected – one is tall (dominant trait) another dwarf (recessive trait).

Complete answer: Hybrid cross can be defined as the cross where two hybrid parents are considered to make a cross.
The cross can be monohybrid, dihybrid, or can be trihybrid.
1. A reciprocal cross is a cross where a pair of crosses is made between a male of a particular strain and the female of another strain and vice versa.
For example, a cross is made between red-eye male drosophila with white eye female drosophila; and the reciprocal cross will be in between white eye male drosophila with red-eye female drosophila.
2. The test cross was first introduced by Mendel.
It involves breeding between an individual with its recessive trait to find out or to analyze the individual is homozygous or heterozygous in nature. This cross also helps to analyze the phenotypic ratios of the offsprings.

So, the correct answer is option C. Test cross.

Note: A back cross is a cross where an individual is crossed with any of its parents whereas in test cross the individual is crossed with its recessive parent.
Thus, it is called all test cross are back cross, but not all back cross is test cross.