Question
Fri September 18, 2009 By: Shivam Jain

Pheno and geno

Expert Reply
Thu September 24, 2009

In plants like 4-0-clock (Mirabilis jalapa) and snapdragon (Antirrhinum) ,if red flowered plants are crossed with white flowered ones, F1 produces all pink flowers. Dominance thus appears to be partial or incomplete. In F2, we get red, white and pink flowers.

Parents                          RR (red)                         ×                rr(white)

 

      Gametes                         R                            ×                 r       

                                             │­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­________________________│

                                                                           

    F1                                                                   Rr(pink)

 

Selfing                              Rr                              ×                   Rr

 

                                                                                                                                    

Male gametes→

 

Female gametes↓                

R

r

R

RR(red)

Rr(pink)

r

Rr(pink)

rr(white)

 

 

 

 

 

 

 

In F2 generation, the phenotypic ratio of red:pink:white flowers = 1:2:1.

The genotypic ratio is RR:Rr:rr = 1:2:1. Thus it can be seen that phenotypic and genotypic ratios are same.  

Related Questions
Sun November 19, 2017

What is meant by gametogenesis?

Home Work Help