Question

howmany phenotypes yields in f2 generation of monohybrid cross​

Answer 1

Explanation:

In F2 generation of a monohybrid cross there is no chance of codominance.

Monohybrid cross is the cross between two traits of same character. The resultant is F1 generation and is in 3:1 ratio. If these F1 generation resultants are self crossed the resultant is similar to F1 generation i.e, 3 organisms of dominant trait and 1 of recessive trait. Hence there is no chance of codomination.

Answer 2

both the genes express themselves equally in the heterozygous condition. Therefore, three different kinds of phenotypes would be seen in the F2 generation in a monohybrid cross.  

Example: Colour inheritance in snapdragon.

Red flower: RR; White flower: rr

F1 generation: RR * rr

                             ↓

                            Rr

F2 generation: Rr * Rr

                            ↓

                    RR Rr Rr rr

Three phenotypes are seen i.e. Red (RR), pink (Rr) and white (rr).

According to the law of dominance, the phenotype of Rr should be red since R is dominant over r. But Snapdragon does not follow Mendelian inheritance. R is not able to completely express itself over r. This results in a third phenotype (here, pink).

Therefore, three phenotypes are seen in F2 generation in a monohybrid cross.