Question

Test cross of dihybrid ratio is 1 : 1 : 1 : 1. It proves that

• A. F₁ hybrid produces four different progeny
• B. F₁ hybrid is homozygous
• C. Two different progeny are produced by P₁ parent
• D. None of these

Answer 1

Answer: (A)

The test cross is a cross between heterozygous $F_1$ hybrid and the double recessive homozygous. The test cross is used to determine whether the individuals exhibiting dominant character are homozygous or heterozygous. A cross between tall heterozygous $F_1$ hybrid with homozygous recessive ($P_1$) produces dominant and recessive character in equal proportion indicating that $F_1$ hybrids are heterozygous (test cross).