Let's use a T for tall and t for short. The genotype of a heterozygous plant will be Tt, which is a tall plant that carries the short gene. After a monohybrid cross, the results are 25% TT (homozygous dominant, tall), 50% Tt (heterozygous, tall), and 25% tt (short). 75% are tall, 25% are short, or 3:1 tall to short.