A pea plant which is homozygous for green pods which are inflated [GGII] is crossed with a homozygous plant for yellow pods which are constricted [ggii]. Answer the following questions:
Give the phenotype and genotype of the F1 generation. Which type of pollination has occurred to produce F1 generation?
Topic: Dihybrid cross — F1 generation
Answer
PHENOTYPE: ALL the F1 plants have GREEN, INFLATED pods. GENOTYPE: ALL are GgIi (heterozygous for both characters).
The pollination is CROSS POLLINATION.
Each parent is homozygous, so each produces only ONE kind of gamete — GI from one and gi from the other. Every offspring therefore receives G and I from one parent and g and i from the other, giving GgIi.
They all LOOK green and inflated because G and I are DOMINANT and mask g and i — MENDEL’S LAW OF DOMINANCE.
THE THIRD PART is easily missed: CROSS POLLINATION, because pollen from one plant has been transferred to the stigma of a DIFFERENT plant. Mendel did this by hand, removing the anthers first (emasculation) so that self-pollination could not occur. In part (iii) the F1 plants are SELF-pollinated instead.