Question

A pea plant with violet colour flower denoted by BB is cross-bred with a pea plant with white flower denoted by ww. (a) What is the expected colour of the flowers in their F1 progeny? (b) What will be the percentage of plants bearing white flower in F2 generation, when the flowers of F1 plants were selfed? (c) State the expected ratio of the genotype BB and Bw in the F2 progeny.

Answer 1

(a) in F1 generation , all flowers will be Violet because Violet colour trait is dominant and white is recessive in plant.

(b) percentage of white flowers is 25% in F2 generation because in F2 generation genotypes of offsprings are 1 BB, 2 Bw, 1 ww ......

(c) ratio of BB and Bw in F2 generation is 1 : 2.

Answer 2

a) violet color flowers

b) 25%

c) BB- 25% and Bw 50%

Explanation:

                      BB                                                                       ww

                violet flowers                                                       white flowers

(Gamete      B       B                                                                w         w

formation)  

( fertilization)       Bw             Bw                   Bw                Bw

                                 All are violet color flowers

                                 Bw              X            Bw

            B            w                                B                        w

              BB             Bw          Bw              ww

   violet                   hybrid violet           white