Question

In Mendel's experiment for one pair of contrasting traits between tall and short pea plants, the ratio between tall and short plants in F2 generation is

Answer 1

ratio of tall plant is 75%and short plant 25%.

Answer 2

in f2 generation one red flowered plant has both R genes,so it is called homozygous dominant trait. Two red flowered plants have R and r genes, so they are called heterozygous. The r genes cannot express as it it recessive. In the presence of R gene it remains masked.One white flowered plant has both RR genes,it is called homozygous recessive trait.
To summarize:
P1: RR (red) X rr (white)
F1: RR( all red)
P2: Rr X Rr
F2
gametes R r
R RR(red) RR(red)
r RR(red) RR(white)
Phenotypic ratio : 3 red : 1 white
Genotypic rati: (Homozygous dominant red):2 (Heterozygous red) :1