Question

The red kernel color in wheat is caused by the presence of at least one dominant allele from each of two independently segregating gene pairs (e.g., R-B-). Wheat plants with rbb genotypes have white kernels, and plants with genotypes R-bb and娟.have yellow kernels. You cross a plant true breeding for red kernels with a plant true breeding for white kernels.
a. What is the expected phenotype(s) and ratios of the Fi plants? [1 pt
b. proportions of the phenotypic classes expected in the What are the relative selfing the F1 progeny? [2 pts] F2 progeny after

Answer 1

Answer:

The correct answer is -

1. Phenotypes: All red kernel, ratio - 4/4 or 100% for both phenotype and genotype (RrBb)

2. 9:6:1 - 9 red, 6 yellow, and 1 white.

Explanation:

In this question, it is given that

R-B- = red kernel color

rrbb = white kernels

R-bb and rrB- = yellow kernels

A cross between true-breeding for the red kernel with true-breeding for the white kernel

RRBB × rrbb

gametes are - RB, RB  and rb, rb

F1  

                   RB                      RB

rb                RrBb                  RrBb

rb                RrBb                  RrBb

Phenotypes: All red kernel,

ratio - 4/4 or 100% for both phenotype and genotype (RrBb)

F2 by selfing RrBb

               RB          Rb         rB         rb

RB        RRBB      RRBb    RrBB     RrBb

Rb        RRBb      RRbb    RrBb     Rrbb

rB         RrBB      RrBb     rrBB      rrBb

rb          RrBb      Rrbb     rrBb      rrbb

phenotypic ratio : 9:6:1

genotypic : 1:1:1:1:2:2:2:2:4