Question

When two hybrids Ttrr & Rrtt are crossed, the phenotypic ratio of offspring shall be?

• A. $3:1$
• B. $1:1:1:1$
• C. $1:1$
• D. $9:3:3:1$

Answer 1

The correct option is B $1:1:1:1$

• When Ttrr x Rrtt is performed, 4 types of phenotypes are obtained in equal numbers. (1:1:1:1)
  
• The gametes for Ttrr are Tr and tr and for Rrtt are Rt and rt.
• The possible genotypes are TtRr, Ttrr, ttRr, ttrr which are all different phenotypically.
• So. the correct answer is '1:1:1:1'.