Question

Please explain monohybrid and dihybrid cross clearly. It is not there in the videos

Answer 1

Monohybrid cross is when only one character is considered in a cross.
A pure tall (TT)plant is crossed with a pure short (tt) plant.The first generation will be tall (Tt) and it is a hybrid plant.When Tt x Tt crossed next generation will be TT,Tt,Tt,tt . 3 tall and 1 short in the second generation.



Dihybrid cross is when two characters are considered at a time in a cross. Tall and round (TTRR) seeded plant is crossed with short and wrinkled (ttrr)seeded plant.
In First generation (F1) all are tall and round(TtRr) .
When F1 generation plants are crossed we get F2 generation .In F2 generation 4 combinations are seen.
Tall round,tall wrinkled,short round and short wrinkled.The ratio is being 9:3:3:1.