Organisms having dissimilar alleles for a character are heterozygous.

Organisms having identical alleles for a character are homozygous.

It is hybrid

It is pure or true breeding.

They form more than one type of gametes.

They form only one type of gamete.

e.g. TT, tt

e.g. Tt

The characters that are expressed in F₁ generation are dominant.

The characters that are not expressed in F₁ generation are recessive.

It is expressed in presence of dominant as well as recessive allele e.g. Tt, TT = tall.

It is expressed only when both the recessive alleles of a gene are present e.g. tt = dwarf

In pea plant tallness, red flowers are dominant characters.

In pea plant dwarfness, white flowers are recessive characters

Dominant character can express in both homozygous as well as heterozygous condition.

Recessive character can be expressed only in homozygous condition.

It is the physical appearance of an organism.

It is the genetic constitution of an organism..

It can be directly seen.

It is determined by inheritance pattern.

Phenotype can be determined from genotype. e.g. Tt = tall

Genotype cannot be determined from phenotype e.g.Tall can be either Tt or TT.

e.g. Tallness, dwarfness

e.g. TT, Tt, tt.