The giant growth gene for oats is recessive, the normal growth gene is dominant.

The giant growth gene for oats is recessive, the normal growth gene is dominant. Which plants need to be crossed to get the same growth offspring?

You need to cross the homozygous plants. If two homozygous normal plants are baptized, then all hybrids will have normal growth. By the same principle, if homozygous giant plants are crossed, then all offspring will be giant (Mendel’s first law). If homozygous normal oats and homozygous giant oats are crossed, then all offspring will be heterozygous, but of the same size. With further crossing of heterozygotes, the offspring will have different sizes (Mendel’s second law).