Mendel’s Pea Cross Ratios

Mendel’s pea plant crosses show how traits can disappear in one generation and return in the next. When he crossed plants, one parental trait sometimes seemed to vanish in the F1 generation and reappear in the F2 generation. Mendel used this pattern to explain why some traits are dominant and others are recessive.

Gregor Mendel performed monohybrid crosses between pea plants that differed in a single trait, such as pod color. He saw one parental phenotype disappear in the first filial, or F1, generation.

The F1 pea plants contain both male and female reproductive structures, allowing them to self-pollinate. When these plants were self-crossed, the m...