A true-breeding (homozygous) line always passes the same allele. CC × CC gives only CC; cc × cc gives only cc.
Cross two different homozygotes — CC × cc — and every offspring is Cc: the uniform F₁ generation.
A true-breeding (homozygous) line always passes the same allele. CC × CC gives only CC; cc × cc gives only cc.
Cross two different homozygotes — CC × cc — and every offspring is Cc: the uniform F₁ generation.